MCP47FEBXX
8-/10-/12-Bit Single/Dual Voltage Output Nonvolatile
Digital-to-Analog Converters with I²C™ Interface
Features
• Operating Voltage Range:
- 2.7V to 5.5V - Full Specifications
- 1.8V to 2.7V - Reduced Device Specifications
• Output Voltage Resolutions:
- 8-bit: MCP47FEB0X (256 Steps)
- 10-bit: MCP47FEB1X (1024 Steps)
- 12-bit: MCP47FEB2X (4096 Steps)
• Rail-to-Rail Output
• Fast Settling Time of 6 µs (typical)
• DAC Voltage Reference Source Options:
- Device VDD
- External VREF pin (buffered or unbuffered)
- Internal Band Gap (1.22V typical)
• Output Gain Options:
- Unity (1x)
- 2x (when not using internal VDD as voltage
source)
• Nonvolatile Memory (EEPROM):
- User-programmed Power-on Reset
(POR)/Brown-out Reset (BOR) output setting
recall and device configuration bits
- Auto Recall of Saved DAC register setting
- Auto Recall of Saved Device Configuration
(Voltage Reference, Gain, Power-Down)
• Power-on/Brown-out Reset Protection
• Nonvolatile Memory Write Protect (WP) Bit
• Power-Down Modes:
- Disconnects output buffer (High Impedance)
- Selection of VOUT pull-down resistors
(100 k or 1 k)
• Low Power Consumption:
- Normal operation: VDD, VI > VPP on HV pins) .......................................................................... ±20 mA
Output clamp current, IOK (VO < 0 or VO > VDD)...................................................................................................±20 mA
Maximum current out of VSS pin
(Single) ..........................................................................................................50 mA
(Dual)...........................................................................................................100 mA
Maximum current into VDD pin
(Single) ..........................................................................................................50 mA
(Dual)...........................................................................................................100 mA
Maximum current sourced by the VOUT pin ............................................................................................................20 mA
Maximum current sunk by the VOUT pin..................................................................................................................20 mA
Maximum current sunk by the VREF pin .................................................................................................................125 µA
Maximum input current source/sunk by SDA, SCL pins ..........................................................................................2 mA
Maximum output current sunk by SDA Output pin .................................................................................................25 mA
Total power dissipation (1) ....................................................................................................................................400 mW
Package power dissipation (TA = +50°C, TJ = +150°C)
TSSOP-8...................................................................................................................................................700 mW
ESD protection on all pins ±4 kV (HBM)
±400V (MM)
±2 kV (CDM)
Latch-Up (per JEDEC JESD78A) @ +125°C ..................................................................................................... ±100 mA
Storage temperature ...............................................................................................................................-65°C to +150°C
Ambient temperature with power applied ...............................................................................................-55°C to +125°C
Soldering temperature of leads (10 seconds) ....................................................................................................... +300°C
Maximum Junction Temperature (TJ) .................................................................................................................... +150°C
† Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is
a stress rating only and functional operation of the device at those or any other conditions above those indicated in the
operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods
may affect device reliability.
Note 1: Power dissipation is calculated as follows:
PDIS = VDD x {IDD - IOH} + {(VDD – VOH) x IOH} + (VOL x IOL)
2015 Microchip Technology Inc.
DS20005375A-page 5
MCP47FEBXX
DC CHARACTERISTICS
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Supply Voltage
Sym.
Min.
Typ.
Max.
Units
Conditions
VDD
2.7
—
5.5
V
1.8
—
2.7
V
DAC operation (reduced analog
specifications) and Serial Interface
—
—
1.7
V
RAM retention voltage (VRAM) < VPOR
VDD voltages greater than VPOR/BOR limit
ensure that device is out of reset.
VDD Voltage
(rising) to ensure device
Power-on Reset
VPOR/BOR
VDD Rise Rate to ensure
Power-on Reset
VDDRR
High-Voltage Commands
Voltage Range (HVC pin)
VHV
VSS
—
12.5
V
The HVC pin will be at one of three input
levels (VIL, VIH or VIHH) (1)
High-Voltage
Input Entry Voltage
VIHHEN
9.0
—
—
V
Threshold for Entry into WiperLock™
Technology
High-Voltage
Input Exit Voltage
VIHHEX
—
—
VDD + 0.8V
V
(Note 1)
Power-on Reset to Output-Driven Delay
TPORD
—
25
50
µs
VDD rising, VDD > VPOR
(Note 3)
V/ms
Note 1
This parameter is ensured by design.
Note 3
POR/BOR voltage trip point is not slope dependent. Hysteresis implemented with time delay.
DS20005375A-page 6
2015 Microchip Technology Inc.
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Supply Current
Power-Down
Current
Sym.
IDD
IDDP
Min.
Typ.
Max.
Units
Conditions
—
—
500
µA
Single
—
—
700
µA
Dual
Serial Interface Active
(Not High-Voltage Command),
VRxB:VRxA = ‘01’ (6),
VOUT is unloaded, VDD = 5.5V
volatile DAC Register = 000h
I2C™: FSCL = 3.4 MHz
—
—
400
µA
Single
—
—
550
µA
Dual
—
—
180
µA
Single
—
—
380
µA
Dual
—
—
180
µA
Single
—
—
380
µA
Dual
—
—
1.9
mA
EE Write Current
VREF = VDD = 5.5V
(after write, Serial Interface is Inactive),
write all 0’s to nonvolatile DAC 0 (address 10h),
VOUT pins are unloaded.
Serial Interface Active (2)
(Not High-Voltage Command),
VRxB:VRxA = ‘10’ (4),
VOUT is unloaded, VREF = VDD = 5.5V
volatile DAC Register = 000h
I2C: FSCL = 3.4 MHz
Serial Interface Inactive (2)
(Not High-Voltage Command),
VRxB:VRxA = ‘00’,
SCL = SDA = VSS, VOUT is unloaded,
volatile DAC Register = 000h
Serial Interface Inactive (2)
(Not High-Voltage Command),
VRxB:VRxA = ‘11’, VREF = VDD,
SCL = SDA = VSS, VOUT is unloaded,
volatile DAC Register = 000h
—
145
180
µA
Single
—
260
400
µA
Dual
HVC = 12.5V (High-Voltage
Command), Serial Interface Inactive
VREF = VDD = 5.5V, LAT/HVC = VIHH,
DAC registers = 000h,
VOUT pins are unloaded.
—
0.65
3.8
µA
PDxB:PDxA = ‘01’ (5),
VOUT not connected
Note 2
This parameter is ensured by characterization.
Note 4
Supply current is independent of current through the resistor ladder in mode VRxB:VRxA = ‘10’.
Note 5
The PDxB:PDxA = ‘01’, ‘10’, and ‘11’ configurations should have the same current.
Note 6
By design, this is worst-case current mode.
2015 Microchip Technology Inc.
DS20005375A-page 7
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Sym.
Min.
Typ.
Max.
Units
Resistor Ladder
Resistance
Resolution
(# of Resistors
and # of Taps) (see
C.1 “Resolution”)
Nominal VOUT
Match (12)
RL
100
140
180
k
N
|VOUT - VOUTMEAN|
/VOUTMEAN
256
1024
4096
—
—
—
0.5
—
15
Taps
Taps
Taps
1.0
1.2
—
Conditions
1.8V VDD 5.5V,
VREF 1.0V(7)
8-bit No Missing Codes
10-bit No Missing Codes
12-bit No Missing Codes
%
2.7V VDD 5.5V(2)
%
1.8V(2)
ppm/°C Code = Mid-scale
(7Fh, 1FFh or 7FFh)
VOUT/T
VOUT Tempco (see
C.19 “VOUT
Temperature
Coefficient”)
VREF pin Input
VREF
VSS
—
VDD
V
1.8V VDD 5.5V(1)
Voltage Range
Note 1
This parameter is ensured by design.
Note 2
This parameter is ensured by characterization.
Note 7
Resistance is defined as the resistance between the VREF pin (mode VRxB:VRxA = ‘10’) to VSS pin. For
dual-channel devices (MCP47FEBX2), this is the effective resistance of the each resistor ladder. The
resistance measurement is of the two resistor ladders measured in parallel.
Note 12 Variation of one output voltage to mean output voltage.
DS20005375A-page 8
2015 Microchip Technology Inc.
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Zero-Scale Error
(see C.5
“Zero-Scale
Error (EZS)”)
(Code = 000h)
Sym.
Min.
Typ.
Max.
Units
EZS
—
—
0.75
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
—
—
3
LSb
2015 Microchip Technology Inc.
8-bit
VRxB:VRxA = ‘11’, Gx = ‘0’,
VREF = VDD, No Load
VRxB:VRxA = ‘00’, Gx = ‘0’,
VDD = 5.5V, No Load
VDD = 1.8V, VREF = 1.0V
VRxB:VRxA = ‘10’, Gx = ‘0’. No Load
VDD = 1.8V, VREF = 1.0V
VRxB:VRxA = ‘11’, Gx = ‘0’. No Load
VRxB:VRxA = ‘01’, Gx = ‘0’, No Load
10-bit
VRxB:VRxA = ‘11’, Gx = ‘0’,
VREF = VDD, No Load
VRxB:VRxA = ‘00’, Gx = ‘0’,
VDD = 5.5V, No Load
VDD = 1.8V, VREF = 1.0V
VRxB:VRxA = ‘10’, Gx = ‘0’. No Load
VDD = 1.8V, VREF = 1.0V
VRxB:VRxA = ‘11’, Gx = ‘0’. No Load
VRxB:VRxA = ‘01’, Gx = ‘0’, No Load
12-bit
VRxB:VRxA = ‘11’, Gx = ‘0’,
VREF = VDD, No Load
VRxB:VRxA = ‘00’, Gx = ‘0’,
VDD = 5.5V, No Load
VDD = 1.8V, VREF = 1.0V
VRxB:VRxA = ‘10’, Gx = ‘0’. No Load
VDD = 1.8V, VREF = 1.0V
VRxB:VRxA = ‘11’, Gx = ‘0’. No Load
VRxB:VRxA = ‘01’, Gx = ‘0’, No Load
LSb
LSb
LSb
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
—
—
12
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
-15
±1.5
+15
LSb
Offset Error
EOS
(see C.7 “Offset
Error (EOS)”)
Offset Voltage
VOSTC
—
±10
—
Temperature
Coefficient
Note 2 This parameter is ensured by characterization.
Conditions
LSb
LSb
LSb
LSb
LSb
LSb
LSb
mV
VRxB:VRxA = ‘00’, Gx = ‘0’, No Load
µV/°C
DS20005375A-page 9
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
DC Characteristics
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
Parameters
Sym.
Min.
Typ.
Max.
Units
Full-Scale Error
(see C.4
“Full-Scale
Error (EFS)”)
EFS
—
—
4.5
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
—
—
18
LSb
Note 2
8-bit
LSb
LSb
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
—
—
70
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
This parameter is ensured by characterization.
LSb
DS20005375A-page 10
Conditions
10-bit
LSb
LSb
LSb
LSb
LSb
12-bit
Code = FFh, VRxB:VRxA = ‘11’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = FFh, VRxB:VRxA = ‘10’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = FFh, VRxB:VRxA = ‘01’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = FFh, VRxB:VRxA = ‘00’,
No Load
Code = 3FFh, VRxB:VRxA = ‘11’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = 3FFh, VRxB:VRxA = ‘10’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = 3FFh, VRxB:VRxA = ‘01’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = 3FFh, VRxB:VRxA = ‘00’,
No Load
Code = FFFh, VRxB:VRxA = ‘11’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = FFFh, VRxB:VRxA = ‘10’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = FFFh, VRxB:VRxA = ‘01’,
Gx = ‘0’, VREF = 2.048V, No Load
Code = FFFh, VRxB:VRxA = ‘00’,
No Load
2015 Microchip Technology Inc.
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Gain Error
(see C.9 “Gain Error
(EG)”)(9)
Sym.
Min.
Typ.
Max.
EG
-1.0
±0.1
+1.0
-1.0
±0.1
+1.0
-1.0
±0.1
+1.0
—
-3
—
-2.5
—
+0.5
Gain-Error Drift (see C.10 G/°C
“Gain-Error Drift (EGD)”)
ET
Total Unadjusted Error
(see C.6 “Total
Unadjusted Error
(ET)”)(2)
See Section 2.0 “Typical
Performance Curves”
-10.0
—
+2.0
See Section 2.0 “Typical
Performance Curves”
-40.0
—
+8.0
See Section 2.0 “Typical
Performance Curves”
Note 2
Note 9
Units
Conditions
% of
8-bit
FSR
% of
10-bit
FSR
% of
12-bit
FSR
ppm/°C
LSb
8-bit
LSb
LSb
10-bit
LSb
LSb
LSb
12-bit
Code = 250, No Load
VRxB:VRxA = ‘00’, Gx = ‘0’
Code = 1000, No Load
VRxB:VRxA = ‘00’, Gx = ‘0’
Code = 4000, No Load
VRxB:VRxA = ‘00’, Gx = ‘0’
VRxB:VRxA = ‘00’.
No Load.
VDD = 1.8V,
VRxB:VRxA = ‘11’, Gx = ‘0’,
VREF = 1.0V, No Load.
VRxB:VRxA = ‘00’.
No Load.
VDD = 1.8V,
VRxB:VRxA = ‘11’, Gx = ‘0’,
VREF = 1.0V, No Load.
VRxB:VRxA = ‘00’.
No Load.
VDD = 1.8V,
VRxB:VRxA = ‘11’, Gx = ‘0’,
VREF = 1.0V, No Load.
This parameter is ensured by characterization.
This gain error does not include offset error.
2015 Microchip Technology Inc.
DS20005375A-page 11
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Sym.
Min.
Typ.
Max.
Units
Integral
Nonlinearity
(see C.11 “Integral
Nonlinearity
(INL)”)(8, 11)
INL
-0.5
±0.1
+0.5
LSb
See Section 2.0 “Typical
Performance Curves”(2)
See Section 2.0 “Typical
Performance Curves”(2)
See Section 2.0 “Typical
Performance Curves”(2)
See Section 2.0 “Typical
Performance Curves”(2)
-1.5
±0.4
+1.5
LSb
See Section 2.0 “Typical
Performance Curves”(2)
See Section 2.0 “Typical
Performance Curves”(2)
See Section 2.0 “Typical
Performance Curves”(2)
See Section 2.0 “Typical
Performance Curves”(2)
-6
±1.5
+6
LSb
Note 2
Note 8
Note 11
LSb
LSb
LSb
LSb
LSb
LSb
LSb
LSb
Conditions
8-bit
VRxB:VRxA = ‘10’
(codes: 6 to 250),
VDD = VREF = 5.5V.
VRxB:VRxA = ‘00’, ‘01’, ‘11’.
VRxB:VRxA = ‘01’,
VDD = 5.5V, Gx = ‘1’.
VRxB:VRxA = ‘10’, ‘11’,
VREF = 1.0V, Gx = ‘1’.
VDD = 1.8V, VREF = 1.0V
10-bit VRxB:VRxA = ‘10’ (codes: 25 to
1000), VDD = VREF = 5.5V.
VRxB:VRxA = ‘00’, ‘01’, ‘11’.
VRxB:VRxA = ‘01’,
VDD = 5.5V, Gx = ‘1’.
VRxB:VRxA = ‘10’, ‘11’,
VREF = 1.0V, Gx = ‘1’.
VDD = 1.8V, VREF = 1.0V.
12-bit VRxB:VRxA = ‘10’ (codes: 100 to
4000), VDD = VREF = 5.5V.
VRxB:VRxA = ‘00’, ‘01’, ‘11’.
See Section 2.0 “Typical
LSb
Performance Curves”(2)
See Section 2.0 “Typical
LSb
VRxB:VRxA = ‘01’,
Performance Curves”(2)
VDD = 5.5V, Gx = ‘1’.
See Section 2.0 “Typical
LSb
VRxB:VRxA = ‘10’, ‘11’,
Performance Curves”(2)
VREF = 1.0V, Gx = ‘1’.
See Section 2.0 “Typical
LSb
VDD = 1.8V, VREF = 1.0V.
Performance Curves”(2)
This parameter is ensured by characterization.
INL and DNL are measured at VOUT with VRL = VDD (VRxB:VRxA = ‘00’).
Code Range dependent on resolution: 8-bit, codes 6 to 250; 10-bit, codes 25 to 1000; 12-bit, 100 to 4000.
DS20005375A-page 12
2015 Microchip Technology Inc.
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Differential
Nonlinearity
(see C.12
“Differential
Nonlinearity
(DNL)”)(8, 11)
Sym.
Min.
Typ.
Max.
Units
DNL
-0.25
±0.0125
+0.25
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
-0.5
±0.05
+0.5
LSb
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
See Section 2.0 “Typical
Performance Curves” (2)
-1.0
±0.2
+1.0
Note 2
Note 8
Note 11
LSb
LSb
LSb
LSb
LSb
LSb
LSb
LSb
LSb
Conditions
8-bit
VRxB:VRxA = ‘10’ (codes: 6 to 250),
VDD = VREF = 5.5V.
Char: VRxB:VRxA = ‘00’, ‘01’, ‘11’.
Char: VRxB:VRxA = ‘01’,
VDD = 5.5V, Gx = ‘1’.
Char: VRxB:VRxA = ‘10’, ‘11’,
VREF = 1.0V, Gx = ‘1’.
VDD = 1.8V
10-bit VRxB:VRxA = ‘10’ (codes: 25 to
1000),
VDD = VREF = 5.5V.
Char: VRxB:VRxA = ‘00’, ‘01’, ‘11’.
Char: VRxB:VRxA = ‘01’,
VDD = 5.5V, Gx = ‘1’.
Char: VRxB:VRxA = ‘10’, ‘11’,
VREF = 1.0V, Gx = ‘1’.
VDD = 1.8V
12-bit VRxB:VRxA = ‘10’ (codes: 100 to
4000), VDD = VREF = 5.5V.
Char: VRxB:VRxA = ‘00’, ‘01’, ‘11’.
See Section 2.0 “Typical
LSb
Performance Curves” (2)
See Section 2.0 “Typical
LSb
Char: VRxB:VRxA = ‘01’,
Performance Curves” (2)
VDD = 5.5V, Gx = ‘1’.
See Section 2.0 “Typical
LSb
Char: VRxB:VRxA = ‘10’, ‘11’,
Performance Curves” (2)
VREF = 1.0V, Gx = ‘1’.
See Section 2.0 “Typical
LSb
VDD = 1.8V
Performance Curves” (2)
This parameter is ensured by characterization.
INL and DNL are measured at VOUT with VRL = VDD (VRxB:VRxA = ‘00’).
Code Range dependent on resolution: 8-bit, codes 6 to 250; 10-bit, codes 25 to 1000; 12-bit, 100 to 4000.
2015 Microchip Technology Inc.
DS20005375A-page 13
MCP47FEBXX
DC CHARACTERISTICS (CONTINUED)
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40°C TA +125°C (Extended)
All parameters apply across the specified operating ranges unless noted.
VDD = +2.7V to 5.5V, VREF = +2.048V to VDD, VSS = 0V,
Gx = ‘0’, RL = 5 k from VOUT to GND, CL = 100 pF.
Typical specifications represent values for VDD = 5.5V, TA = +25°C.
DC Characteristics
Parameters
Sym.
Min.
Typ.
Max.
Units
-3 dB Bandwidth
(see C.16 “-3 dB
Bandwidth”)
BW
—
86.5
—
kHz
—
67.7
—
kHz
VOUT(MIN)
—
0.01
—
VOUT(MAX)
—
—
PM
—
VDD –
0.04
66
—
SR
ISC
—
3
0.44
9
—
14
VBG
VBGTC
1.18
—
1.22
15
1.26
—
V
ppm/°C
2.0
2.2
—
—
5.5
5.5
V
V
VREF pin voltage stable
VOUT output linear
VSS
VSS
—
—
—
—
1
-64
VDD – 0.04
VDD
—
—
V
V
pF
dB
VRxB:VRxA = ‘11’ (buffered mode)
VRxB:VRxA = ‘10’ (unbuffered mode)
VRxB:VRxA = ‘10’ (unbuffered mode)
VREF = 2.048V ± 0.1V,
VRxB:VRxA = ‘10’, Gx = ‘0’,
Frequency = 1 kHz
Output Amplifier
Minimum Output
Voltage
Maximum Output
Voltage
Phase Margin
Slew Rate (10)
Short-Circuit Current
Internal Band Gap
Band Gap Voltage
Band Gap Voltage
Temperature
Coefficient
Operating Range
(VDD)
External Reference (VREF)
Input Range (1)
VREF
Input Capacitance
Total Harmonic
Distortion (1)
CREF
THD
Conditions
VREF = 2.048V ± 0.1V,
VRxB:VRxA = ‘10’, Gx = ‘0’
VREF = 2.048V ± 0.1V,
VRxB:VRxA = ‘10’, Gx = ‘1’
1.8V VDD 5.5V,
Output Amplifier’s minimum drive
V
1.8V VDD 5.5V,
Output Amplifier’s maximum drive
Degree CL = 400 pF, RL =
(°)
V/µs
RL = 5 k
mA
DAC code = Full Scale
V
Dynamic Performance
Major Code
—
45
—
nV-s
1 LSb change around major carry
Transition Glitch (see
(7FFh to 800h)
C.14 “Major-Code
Transition Glitch”)
Digital Feedthrough
—
VPOR
VOUT driven to VOUT disabled
Power-Down Output
Disable Time Delay
TPDD
—
10.5
—
µs
PDxB:PDxA = ‘11’, ‘10’, or ‘01’ -> “00” started from falling edge of the SCL at the end of the 8th clock cycle.
Volatile DAC Register = FFh, VOUT = 10 mV. VOUT not
connected.
Power-Down Output
Enable Time Delay
TPDE
—
1
—
µs
PDxB:PDxA = “00” ‘11’, ‘10’, or ‘01’ started from
falling edge of the SCL at the end of the 8th clock cycle.
VOUT = VOUT - 10 mV. VOUT not connected.
2015 Microchip Technology Inc.
Max. Units
Conditions
DS20005375A-page 19
MCP47FEBXX
SCL
91
90
93
92
SDA
Start
Condition
96
94
95
ACK/ACK
Pulse
Stop
Condition
96
LAT
I2C™ Bus Start/Stop Bits Timing Waveforms.
FIGURE 1-4:
VIH
SCL
93
91
90
92
111
SDA
VIL
Start
Condition
FIGURE 1-5:
DS20005375A-page 20
Stop
Condition
I2C™ Bus Start/Stop Bits Timing Waveforms.
2015 Microchip Technology Inc.
MCP47FEBXX
I2C BUS START/STOP BITS AND LAT REQUIREMENTS
TABLE 1-3:
I2C™ AC Characteristics
Param.
Symbol
No.
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40C TA +125C (Extended)
Operating Voltage range is described in DC Characteristics
Characteristic
90
91
92
93
Cb
TSU:STA
THD:STA
TSU:STO
THD:STO
Max.
Units
0
100
kHz
Cb = 400 pF, 1.8V - 5.5V(2)
Fast Mode
0
400
kHz
Cb = 400 pF, 2.7V - 5.5V
High-Speed 1.7
0
1.7
MHz
Cb = 400 pF, 4.5V - 5.5V
Cb = 100 pF, 4.5V - 5.5V
Standard Mode
FSCL
D102
Min.
Bus Capacitive
Loading
Start Condition
Setup Time
(Only relevant for
repeated Start
condition)
Start Condition
Hold time
(After this period the
first clock pulse is
generated)
Stop Condition
Setup Time
Stop Condition
Hold Time
High-Speed 3.4
0
3.4
MHz
100 kHz mode
—
400
pF
400 kHz mode
—
400
pF
1.7 MHz mode
—
400
pF
3.4 MHz mode
—
100
pF
100 kHz mode
4700
—
ns
400 kHz mode
600
—
ns
1.7 MHz mode
160
—
ns
3.4 MHz mode
160
—
ns
100 kHz mode
4000
—
ns
400 kHz mode
600
—
ns
1.7 MHz mode
160
—
ns
3.4 MHz mode
160
—
ns
100 kHz mode
4000
—
ns
400 kHz mode
600
—
ns
1.7 MHz mode
160
—
ns
3.4 MHz mode
160
—
ns
100 kHz mode
4000
—
ns
400 kHz mode
600
—
ns
1.7 MHz mode
160
—
ns
3.4 MHz mode
Conditions
Note 2
Note 2
Note 2
Note 2
160
—
ns
94
TLATSU
LAT ↑ to SCL↑ (write data ACK bit)
Setup Time
10
—
ns
Write Data delayed(3)
95
TLATHD
SCL ↑ to LAT↑ (write data ACK bit)
Hold Time
250
—
ns
Write Data delayed(3)
96
TLAT
LAT High or Low Time
50
—
ns
97
THVCSU
HVC High to SCL High
(of Start condition) - Setup Time
25
—
µs
High-Voltage Commands
98
THVCHD
SCL Low (of Stop condition) to
HVC Low - Hold Time
25
—
µs
High-Voltage Commands
Note 2
Not Tested. This parameter ensured by characterization.
Note 3
The transition of the LAT signal between 10 ns before the rising edge (Spec 94) and 250 ns after the rising
edge (Spec 95) of the SCL signal is indeterminate whether the change in VOUT is delayed or not.
2015 Microchip Technology Inc.
DS20005375A-page 21
MCP47FEBXX
103
102
100
101
SCL
90
106
91
92
107
SDA
In
110
109
109
SDA
Out
I2C™ Bus Timing Waveforms.
FIGURE 1-6:
TABLE 1-4:
I2C BUS REQUIREMENTS (SLAVE MODE)
I2C™ AC Characteristics
Param.
No.
Sym.
100
THIGH
101
102A
(2)
102B(2)
Note 2
TLOW
TRSCL
TRSDA
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40C TA +125C (Extended)
Operating Voltage range is described in DC Characteristics
Characteristic
Clock high time
Clock low time
SCL rise time
SDA rise time
Min.
Max.
Units
Conditions
100 kHz mode
4000
—
ns
1.8V-5.5V(2)
400 kHz mode
600
—
ns
2.7V-5.5V
1.7 MHz mode
120
—
ns
4.5V-5.5V
3.4 MHz mode
60
—
ns
4.5V-5.5V
100 kHz mode
4700
—
ns
1.8V-5.5V(2)
400 kHz mode
1300
—
ns
2.7V-5.5V
1.7 MHz mode
320
—
ns
4.5V-5.5V
3.4 MHz mode
160
—
ns
4.5V-5.5V
100 kHz mode
—
1000
ns
Cb is specified to be from
10 to 400 pF (100 pF
maximum for 3.4 MHz
mode)
400 kHz mode
20 + 0.1Cb
300
ns
1.7 MHz mode
20
80
ns
1.7 MHz mode
20
160
ns
3.4 MHz mode
10
40
ns
3.4 MHz mode
10
80
ns
After a Repeated Start
condition or an
Acknowledge bit
Cb is specified to be from
10 to 400 pF (100 pF
maximum for 3.4 MHz
mode)
100 kHz mode
—
1000
ns
400 kHz mode
20 + 0.1Cb
300
ns
1.7 MHz mode
20
160
ns
3.4 MHz mode
10
80
ns
After a Repeated Start
condition or an
Acknowledge bit
Not Tested. This parameter ensured by characterization.
DS20005375A-page 22
2015 Microchip Technology Inc.
MCP47FEBXX
TABLE 1-5:
I2C BUS REQUIREMENTS (SLAVE MODE) (CONTINUED)
I2C™ AC Characteristics
Param.
No.
Sym.
103A(2)
TFSCL
103B
(2)
106
107
109
TFSDA
THD:DAT
TSU:DAT
TAA
Standard Operating Conditions (unless otherwise specified)
Operating Temperature
–40C TA +125C (Extended)
Operating Voltage range is described in DC Characteristics
Characteristic
SCL fall time
SDA fall time
Data input hold
time
Data input
setup time
Output valid
from clock
111
TBUF
TSP
Bus free time
Input filter spike
suppression
(SDA and SCL)
Max.
Units
100 kHz mode
—
300
ns
400 kHz mode
20 + 0.1Cb
300
ns
1.7 MHz mode
20
80
ns
3.4 MHz mode
10
40
ns
100 kHz mode
—
300
ns
Conditions
Cb is specified to be from
10 to 400 pF
(100 pF maximum for
3.4 MHz mode)(4)
Cb is specified to be from
10 to 400 pF
(100 pF maximum for
3.4 MHz mode)(4)
400 kHz mode
20 + 0.1Cb
300
ns
1.7 MHz mode
20
160
ns
3.4 MHz mode
10
80
ns
100 kHz mode
0
—
ns
1.8V-5.5V(2, 5)
400 kHz mode
0
—
ns
2.7V-5.5V(5)
1.7 MHz mode
0
—
ns
4.5V-5.5V(5)
3.4 MHz mode
0
—
ns
4.5V-5.5V(5)
100 kHz mode
250
—
ns
Note 2, Note 6
Note 6
400 kHz mode
100
—
ns
1.7 MHz mode
10
—
ns
3.4 MHz mode
10
—
ns
100 kHz mode
—
3450
ns
400 kHz mode
—
900
ns
Note 7
1.7 MHz mode
—
150
ns
Cb = 100 pF(7, 8)
—
310
ns
Cb = 400 pF(2, 7)
—
150
ns
Cb = 100 pF(7)
Time the bus must be free
before a new transmission can start(2)
3.4 MHz mode
110
Min.
Note 2, Note 7
100 kHz mode
4700
—
ns
400 kHz mode
1300
—
ns
1.7 MHz mode
N.A.
—
ns
3.4 MHz mode
N.A.
—
ns
100 kHz mode
—
50
ns
400 kHz mode
—
50
ns
1.7 MHz mode
—
10
ns
Spike suppression
3.4 MHz mode
—
10
ns
Spike suppression
NXP Spec states N.A.(2)
Note 2
Not Tested. This parameter ensured by characterization.
Note 4
Use Cb in pF for the calculations.
Note 5
A Master Transmitter must provide a delay to ensure that difference between SDA and SCL fall times do
not unintentionally create a Start or Stop condition.
Note 6
A fast-mode (400 kHz) I2C-bus device can be used in a standard-mode (100 kHz) I2C-bus system, but the
requirement tSU;DAT 250 ns must then be met. This will automatically be the case if the device does not
stretch the Low period of the SCL signal. If such a device does stretch the Low period of the SCL signal, it
must output the next data bit to the SDA line TR max.+tSU;DAT = 1000 + 250 = 1250 ns (according to the
standard-mode I2C bus specification) before the SCL line is released.
Note 7
As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region
(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
Note 8
Ensured by the TAA 3.4 MHz specification test.
2015 Microchip Technology Inc.
DS20005375A-page 23
MCP47FEBXX
Timing Table Notes:
1.
2.
3.
4.
5.
6.
7.
8.
Within 1/2 LSb of final value when code changes from 1/4 to 3/4 of FSR. (Example: 400h to C00h in 12- bit device).
Not Tested. This parameter ensured by characterization.
The transition of the LAT signal between 10 ns before the rising edge (Spec 94) and 250 ns after the rising edge
(Spec 95) of the SCL signal is indeterminate whether the change in VOUT is delayed or not.
Use Cb in pF for the calculations.
A Master Transmitter must provide a delay to ensure that difference between SDA and SCL fall times do not
unintentionally create a Start or Stop condition.
A fast-mode (400 kHz) I2C-bus device can be used in a standard-mode (100 kHz) I2C-bus system, but the
requirement tSU;DAT 250 ns must then be met. This will automatically be the case if the device does not stretch
the Low period of the SCL signal. If such a device does stretch the Low period of the SCL signal, it must output
the next data bit to the SDA line
TR max.+tSU;DAT = 1000 + 250 = 1250 ns (according to the standard-mode I2C bus specification) before the SCL
line is released.
As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region (minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
Ensured by the TAA 3.4 MHz specification test.
DS20005375A-page 24
2015 Microchip Technology Inc.
MCP47FEBXX
TEMPERATURE SPECIFICATIONS
Electrical Specifications: Unless otherwise indicated, VDD = +2.7V to +5.5V, VSS = GND.
Parameters
Symbol
Min.
Typical
Max.
Units
Specified Temperature Range
TA
-40
—
+125
°C
Operating Temperature Range
TA
-40
—
+125
°C
Storage Temperature Range
TA
-65
—
+150
°C
JA
—
139
—
°C/W
Conditions
Temperature Ranges
Note 1
Thermal Package Resistances
Thermal Resistance, 8L-TSSOP
Note 1:
The MCP47FEBXX devices operate over this extended temperature range, but with reduced performance.
Operation in this range must not cause TJ to exceed the Maximum Junction Temperature of +150°C.
2015 Microchip Technology Inc.
DS20005375A-page 25
MCP47FEBXX
NOTES:
DS20005375A-page 26
2015 Microchip Technology Inc.
MCP47FEBXX
2.0
Note:
TYPICAL PERFORMANCE CURVES
The device Performance Curves are available in a separate document. This is done to keep the file size of
this PDF document less than the 10 MB file attachment limit of many mail servers.
The MCP47FXBXX Performance Curves document is literature number DS20005378, and can be found
on the Microchip website. Look at the MCP47FEBXX product page under “Documentation and Software”,
in the Data Sheets category.
2015 Microchip Technology Inc.
DS20005375A-page 27
MCP47FEBXX
NOTES:
DS20005375A-page 28
2015 Microchip Technology Inc.
MCP47FEBXX
3.0
PIN DESCRIPTIONS
Overviews of the pin functions are provided in
Sections 3.1 “Positive Power Supply Input (VDD)”
through Section 3.8 “I2C - Serial Data Pin (SDA)”.
The descriptions of the pins for the single-DAC output
device are listed in Table 3-1, and descriptions for the
dual-DAC output device are listed in Table 3-2.
TABLE 3-1:
MCP47FEBX1 (SINGLE-DAC) PINOUT DESCRIPTION
Pin
TSSOP-8L
Symbol
I/O
Buffer
Type
Standard Function
1
VDD
—
P
Supply Voltage Pin
2
VREF0
A
Analog
Voltage Reference Input Pin
3
VOUT0
A
Analog
Buffered analog voltage output pin
4
NC
—
—
Not Internally Connected
5
VSS
—
P
Ground reference pin for all circuitries on the device
6
LAT0/HVC
I
HV ST
7
SCL
I
ST
I2C™ Serial Clock Pin
8
SDA
I/O
ST
I2C Serial Data Pin
Legend:
TABLE 3-2:
A = Analog
I = Input
DAC Register Latch/High-Voltage Command Pin. Latch Pin allows the
value in the Serial Shift Register to transfer to the volatile DAC register.
High-Voltage Command allows User Configuration bits to be written.
ST = Schmitt Trigger
O = Output
I/O = Input/Output
P = Power
MCP47FEBX2 (DUAL-DAC) PINOUT DESCRIPTION
Pin
TSSOP-8
Symbol
I/O
Buffer
Type
Standard Function
1
VDD
—
P
Supply Voltage Pin
2
VREF
A
Analog
Voltage Reference Input Pin (for DAC0 or DAC0 and DAC1)
3
VOUT0
A
Analog
Buffered analog voltage output 0 pin (DAC0 output)
4
VOUT1
A
Analog
Buffered analog voltage output 1 pin (DAC1 output)
5
VSS
—
P
Ground reference pin for all circuitries on the device
6
LAT/HVC
I
HV ST
7
SCL
I
ST
I2C™ Serial Clock Pin
8
SDA
I/O
ST
I2C Serial Data Pin
Legend:
A = Analog
I = Input
2015 Microchip Technology Inc.
DAC Register Latch/High-Voltage Command Pin. Latch Pin allows the
value in the Serial Shift Register to transfer to the volatile DAC register(s)
(for DAC0 or DAC0 and DAC1). High-Voltage Command allows User
Configuration bits to be written.
ST = Schmitt Trigger
O = Output
I/O = Input/Output
P = Power
DS20005375A-page 29
MCP47FEBXX
3.1
Positive Power Supply Input (VDD)
VDD is the positive supply voltage input pin. The input
supply voltage is relative to VSS.
The power supply at the VDD pin should be as clean as
possible for a good DAC performance. It is
recommended to use an appropriate bypass capacitor
of about 0.1 µF (ceramic) to ground. An additional
10 µF capacitor (tantalum) in parallel is also
recommended to further attenuate noise present in
application boards.
3.2
Voltage Reference Pin (VREF)
The VREF pin is either an input or an output. When the
DAC’s voltage reference is configured as the VREF pin,
the pin is an input. When the DAC’s voltage reference is
configured as the internal band gap, the pin is an output.
When the DAC’s voltage reference is configured as the
VREF pin, there are two options for this voltage input:
VREF pin voltage buffered or unbuffered. The buffered
option is offered in cases where the external reference
voltage does not have sufficient current capability to not
drop it’s voltage when connected to the internal resistor
ladder circuit.
When the DAC’s voltage reference is configured as the
device VDD, the VREF pin is disconnected from the
internal circuit.
When the DAC’s voltage reference is configured as the
internal band gap, the VREF pin’s drive capability is
minimal, so the output signal should be buffered.
See Section 5.2 “Voltage Reference Selection” and
Register 4-2 for more details on the Configuration bits.
3.3
Analog Output Voltage Pin (VOUT)
VOUT is the DAC analog voltage output pin. The DAC
output has an output amplifier. The DAC output range is
dependent on the selection of the voltage reference
source (and potential Output Gain selection). These are:
• Device VDD - The full-scale range of the DAC
output is from VSS to approximately VDD.
• VREF pin - The full-scale range of the DAC output
is from VSS to G VRL, where G is the gain
selection option (1x or 2x).
• Internal Band Gap - The full-scale range of the
DAC output is from VSS to G (2 VBG), where G
is the gain selection option (1x or 2x).
3.5
Ground (VSS)
The VSS pin is the device ground reference.
The user must connect the VSS pin to a ground plane
through a low-impedance connection. If an analog
ground path is available in the application PCB (printed
circuit board), it is highly recommended that the VSS pin
be tied to the analog ground path or isolated within an
analog ground plane of the circuit board.
3.6
Latch Pin (LAT)/High-Voltage
Command (HVC)
The LAT pin is used to force the transfer of the DAC
register’s shift register to the DAC output register. This
allows DAC outputs to be updated at the same time.
The update of the VRxB:VRxA, PDxB:PDxA, Gx bits
are also controlled by the LAT pin state.
The HVC pin allows the device’s nonvolatile user configuration bits to be programmed when the HVC pin is
greater than the VIHH entry voltage.
3.7
I2C - Serial Clock Pin (SCL)
The SCL pin is the serial clock pin of the I2C interface.
The MCP47FEBXX’s I2C interface only acts as a slave
and the SCL pin accepts only external serial clocks.
The input data from the Master device is shifted into the
SDA pin on the rising edges of the SCL clock and
output from the device occurs at the falling edges of the
SCL clock. The SCL pin is an open-drain N-channel
driver. Therefore, it needs an external pull-up resistor
from the VDD line to the SCL pin. Refer to Section 6.0
“I2C Serial Interface Module” for more details of I2C
Serial Interface communication.
3.8
I2C - Serial Data Pin (SDA)
The SDA pin is the serial data pin of the I2C interface.
The SDA pin is used to write or read the DAC registers
and Configuration bits. The SDA pin is an open-drain
N-channel driver. Therefore, it needs an external
pull-up resistor from the VDD line to the SDA pin. Except
for Start and Stop conditions, the data on the SDA pin
must be stable during the high period of the clock. The
high or low state of the SDA pin can only change when
the clock signal on the SCL pin is low. Refer to
Section 6.0 “I2C Serial Interface Module” for more
details of I2C Serial Interface communication.
In Normal mode, the DC impedance of the output pin is
about 1. In Power-Down mode, the output pin is
internally connected to a known pull-down resistor of
1 k, 100 k, or open. The Power-Down selection bits
settings are shown Register 4-3 (Table 5-5).
3.4
No Connect (NC)
The NC pin is not connected to the device.
DS20005375A-page 30
2015 Microchip Technology Inc.
MCP47FEBXX
4.0
GENERAL DESCRIPTION
The MCP47FEBX1 (MCP47FEB01, MCP47FEB11,
and MCP47FEB21) devices are single-channel voltage
output devices. MCP47FEBX2 (MCP47FEB02,
MCP47FEB12, and MCP47FEB22) devices are dualchannel voltage output devices.
These devices are offered with 8-bit (MCP47FEB0X),
10-bit (MCP47FEB1X) and 12-bit (MCP47FEB2X)
resolution and include nonvolatile memory (EEPROM),
an I2C serial interface and a write latch (LAT) pin to
control the update of the written DAC value to the DAC
output pin.
The devices use a resistor ladder architecture. The
resistor ladder DAC is driven from a softwareselectable voltage reference source. The source can
be either the device’s internal VDD, an external VREF
pin voltage (buffered or unbuffered) or an internal band
gap voltage source.
The DAC output is buffered with a low power and
precision output amplifier (op amp). This output
amplifier provides a rail-to-rail output with low offset
voltage and low noise. The gain (1x or 2x) of the
output buffer is software configurable.
4.1
Power-on Reset/Brown-out Reset
(POR/BOR)
The internal Power-on Reset (POR)/Brown-out Reset
(BOR) circuit monitors the power supply voltage (VDD)
during operation. This circuit ensures correct device
start-up at system power-up and power-down events.
The device’s RAM retention voltage (VRAM) is lower
than the POR/BOR voltage trip point (VPOR/VBOR).
The maximum VPOR/VBOR voltage is less than 1.8V.
POR occurs as the voltage is rising (typically from 0V),
while BOR occurs as the voltage is falling (typically
from VDD(MIN) or higher).
The POR and BOR trip points are at the same voltage,
and the condition is determined by whether the VDD
voltage is rising or falling (see Figure 4-1). What occurs is
different depending on if the reset is a POR or BOR reset.
the
electrical
When
VPOR/VBOR < VDD < 2.7V,
performance may not meet the data sheet
specifications. In this region, the device is capable of
reading and writing to its EEPROM and reading and
writing to its volatile memory if the proper serial
command is executed.
This device also has user-programmable nonvolatile
memory (EEPROM), which allows the user to save the
desired POR/BOR value of the DAC register and
device configuration bits. High Voltage lock bits can be
used to ensure that the devices output settings are not
accidentally modified.
The devices operates from a single supply voltage.
This voltage is specified from 2.7V to 5.5V for full
specified operation, and from 1.8V to 5.5V for digital
operation. The device operates between 1.8V and
2.7V, but some device parameters are not specified.
The main functional blocks are:
•
•
•
•
•
•
Power-on Reset/Brown-out Reset (POR/BOR)
Device Memory
Resistor Ladder
Output Buffer/VOUT Operation
Internal Band Gap (Voltage Reference)
I2C Serial Interface Module
2015 Microchip Technology Inc.
DS20005375A-page 31
MCP47FEBXX
4.1.1
POWER-ON RESET
4.1.2
The Power-on Reset is the case where the device VDD
is having power applied to it from the VSS voltage level.
As the device powers-up, the VOUT pin will float to an
unknown value. When the device’s VDD is above the
transistor threshold voltage of the device, the output
will start being pulled low. After the VDD is above the
POR/BOR trip point (VBOR/VPOR), the resistor
network’s wiper will be loaded with the POR value
(mid-scale). The volatile memory determines the
analog output (VOUT) pin voltage. After the device is
powered-up, the user can update the device memory.
When the rising VDD voltage crosses the VPOR trip
point, the following occurs:
• Nonvolatile DAC register value latched into
volatile DAC register
• Nonvolatile Configuration bit values latched into
volatile Configuration bits
• POR Status bit is set (‘1’)
• The Reset Delay Timer (tPORD) starts; when the
reset delay timer (tPORD) times out, the I2C serial
interface is operational. During this delay time, the
I2C interface will not accept commands.
• The Device Memory Address pointer is forced to
00h.
BROWN-OUT RESET
The Brown-out Reset occurs when a device had
power applied to it, and that power (voltage) drops
below the specified range.
When the falling VDD voltage crosses the VPOR trip
point (BOR event), the following occurs:
• Serial Interface is disabled
• EEPROM Writes are disabled
• Device is forced into a power-down state
(PDxB:PDxA = ‘11’). Analog circuitry is turned off.
• Volatile DAC Register is forced to 000h
• Volatile configuration bits VRxB:VRxA and Gx are
forced to ‘0’
If the VDD voltage decreases below the VRAM voltage,
all volatile memory may become corrupted.
As the voltage recovers above the VPOR/VBOR voltage
see Section 4.1.1 “Power-on Reset”.
Serial commands not completed due to a brown-out
condition may cause the memory location (volatile and
nonvolatile) to become corrupted.
Figure 4-1 illustrates the conditions for power-up and
power-down events under typical conditions.
The analog output (VOUT) state will be determined by
the state of the volatile Configuration bits and the DAC
register. This is called a Power-on Reset (event).
Figure 4-1 illustrates the conditions for power-up and
power-down events under typical conditions.
Volatile memory
POR starts Reset Delay Timer.
retains data value When timer times out, I2C™ interface
can operate (if VDD VDD(MIN))
Volatile memory
becomes corrupted
VDD(MIN)
TPORD (20 µs max.)
VPOR
VBOR
VRAM
Normal Operation
Device in
unknown
state
Device in
POR state
POR reset forced active
FIGURE 4-1:
DS20005375A-page 32
EEPROM data latched into volatile
configuration bits and DAC register.
POR status bit is set (‘1’)
Below
minimum
operating
voltage
Device Device in
in power unknown
down
state
state
BOR reset,
volatile DAC Register = 000h
volatile VRxB:VRxA = 00
volatile Gx = 0
volatile PDxB:PDxA = 11
Power-on Reset Operation.
2015 Microchip Technology Inc.
MCP47FEBXX
4.2
Device Memory
4.2.2
User memory includes three types of memory:
This memory can be grouped into two uses of nonvolatile memory. These are the DAC Output Value and
Configuration registers:
• Volatile Register Memory (RAM)
• Nonvolatile Register Memory
• Device Configuration Memory
Each memory address is 16 bits wide. There are five
nonvolatile user-control bits that do not reside in memory mapped register space (see Section 4.2.3
“Device Configuration Memory”).
4.2.1
VOLATILE REGISTER MEMORY
(RAM)
DAC0 and DAC1 Output Value Registers
VREF Select Register
Power-Down Configuration Register
Gain and Status Register
WiperLock Technology Status Register
The device starts writing the EEPROM memory
location at the completion of the serial interface
command. For the I2C interface, this is the
acknowledge pulse of the EEPROM write command.
The volatile memory starts functioning when the
device VDD is at (or above) the RAM retention voltage
(VRAM). The volatile memory will be loaded with the
default device values when the VDD rises across the
VPOR/VBOR voltage trip point.
Note:
When the nonvolatile memory is written,
the corresponding volatile memory is not
modified.
The nonvolatile DAC registers enables stand-alone
operation of the device (without Microcontroller control)
after being programmed to the desired value.
MEMORY MAP (x16)
Address
CL0
10h
Nonvolatile DAC0 Register
DL0
CL1
11h
Nonvolatile DAC1 Register
DL1
—
12h
Reserved
—
Reserved
—
13h
Reserved
—
Reserved
—
14h
Reserved
—
05h
Reserved
—
15h
Reserved
—
06h
Reserved
—
16h
Reserved
—
07h
Reserved
—
17h
Reserved
—
08h
VREF Register
—
18h
Nonvolatile VREF Register
—
Function
00h
Volatile DAC0 Register
01h
Volatile DAC1 Register
02h
Reserved
03h
04h
Config
Bit (1)
Config
Bit (1)
Address
TABLE 4-1:
• Nonvolatile DAC0 and DAC1 Output Value Registers
• Nonvolatile VREF Select Register
• Nonvolatile Power Down Configuration Register
• Nonvolatile Gain and I2C Slave Address
The nonvolatile memory starts functioning below the
device’s VPOR/VBOR trip point and is loaded into the
corresponding volatile registers whenever the device
rises above the POR/BOR voltage trip point.
There are up to six Volatile Memory locations:
•
•
•
•
•
NONVOLATILE REGISTER
MEMORY
Function
09h
Power-Down Register
—
19h
Nonvolatile Power-Down Register
0Ah
Gain and Status Register
—
1Ah
NV Gain and I2C™ 7-bits Slave Address
—
SALCK
0Bh
WiperLock Technology Status Register
—
1Bh
Reserved
—
0Ch
Reserved
—
1Ch
Reserved
—
0Dh
Reserved
—
1Dh
Reserved
—
0Eh
Reserved
—
1Eh
Reserved
—
0Fh
Reserved
—
1Fh
Reserved
—
Volatile Memory address range
Nonvolatile Memory address range
Note 1:Device Configuration Memory bits requires a High-Voltage Enable or Disable Command (LAT/LAT0 = VIHH,
or CS = VIHH) to modify the bit value.
2015 Microchip Technology Inc.
DS20005375A-page 33
MCP47FEBXX
4.2.3
DEVICE CONFIGURATION
MEMORY
4.2.5
UNIMPLEMENTED (RESERVED)
LOCATIONS
There are up to five nonvolatile user bits that are not
directly mapped into the address space. These
nonvolatile device configuration bits control the
following functions:
Normal (Voltage) Commands (Read or Write) to any
unimplemented memory address (Reserved) will result
in a Command Error condition (NACK). Read
Commands of a reserved location will read bits as ‘1’.
• DAC Register and Configuration WiperLock
Technology (2 bits per DAC)
• I2C Slave Address Write Protect (Lock)
High-Voltage Commands (Enable or Disable) to any
unimplemented Configuration bits will result in a
Command Error condition (NACK).
The Status register shows the states of the device
WiperLock Technology configuration bits. The
STATUS register is described in Register 4-6.
4.2.5.1
The operation of WiperLock Technology is discussed
in Section 4.2.6 “WiperLock Technology” while I2C
Slave Address Write Protect is discussed in
Section 4.2.7 “I2C Slave Address Write Protect”.
4.2.4
Table 4-2 shows the default factory POR initialization
of the device memory map for the 8-, 10- and 12-bit
devices.
Note:
UNIMPLEMENTED REGISTER BITS
Read Commands of a valid location will read unimplemented bits as ‘0’.
POR/BOR Value
Address
The Volatile memory locations will be determined by the nonvolatile memory states
(registers and device configuration bits).
FACTORY DEFAULT POR / BOR VALUES
POR/BOR Value
10-bit
12-bit
8-bit
10-bit
12-bit
Function
8-bit
Function
Address
TABLE 4-2:
Default Factory POR Memory State
of Nonvolatile Memory (EEPROM)
00h Volatile DAC0 Register
7Fh
1FFh
7FFh
10h Nonvolatile DAC0 Register
7Fh
1FFh
7FFh
01h Volatile DAC1 Register
7Fh
1FFh
7FFh
11h Nonvolatile DAC1 Register
7Fh
1FFh
7FFh
12h Reserved
(2)
FFh
3FFh
FFFh
13h Reserved
(2)
FFh
3FFh
FFFh
14h Reserved
(2)
FFh
3FFh
FFFh
15h Reserved
(2)
FFh
3FFh
FFFh
16h Reserved
(2)
FFh
3FFh
FFFh
17h Reserved
(2)
FFh
3FFh
FFFh
02h Reserved
(2)
03h Reserved
(2)
04h Reserved
(2)
05h Reserved
(2)
06h Reserved
(2)
07h Reserved
(2)
FFh
FFh
FFh
FFh
FFh
FFh
3FFh
3FFh
3FFh
3FFh
3FFh
3FFh
FFFh
FFFh
FFFh
FFFh
FFFh
FFFh
08h VREF Register
0000h 0000h 0000h
18h Nonvolatile VREF
Register
0000h 0000h 0000h
09h Power-Down Register
0000h 0000h 0000h
19h Nonvolatile Power-Down
Register
0000h 0000h 0000h
0Ah Gain and Status Register
0080h 0080h 0080h
1Ah NV Gain and I2C™ 7-bit
Slave Address (1)
00E0h 00E0h 00E0h
0Bh WiperLock Technology
Status Register
0000h 0000h 0000h
(1 )
(1 )
(1 )
1Bh Reserved (2)
FFh
3FFh
FFFh
0Ch Reserved (2)
FFh
3FFh
FFFh
1Ch Reserved (2)
FFh
3FFh
FFFh
0Dh Reserved (2)
FFh
3FFh
FFFh
1Dh Reserved (2)
FFh
3FFh
FFFh
(2)
FFh
3FFh
FFFh
FFh
3FFh
FFFh
(2)
FFh
3FFh
FFFh
1Eh Reserved
0Fh Reserved (2)
FFh
3FFh
FFFh
1Fh Reserved (2)
0Eh Reserved
Volatile Memory address range
Note 1:
2:
Nonvolatile Memory address range
A0 I2C 7-bit Slave Address option is ’110 0000’ and the Slave Address Lock (SALCK) bit is enabled (‘1’).
Reading a reserved memory location will result in the I2C command to Not ACK the command byte. The device
data bits will output all ‘1’s. A Start condition will reset the I2C interface.
DS20005375A-page 34
2015 Microchip Technology Inc.
MCP47FEBXX
4.2.6
WIPERLOCK TECHNOLOGY
The MCP47FEBXX device’s WiperLock technology
allows application-specific device settings (DAC register and configuration) to be secured without requiring
the use of an additional write-protect pin. There are
two configuration bits (DLx:CLx) for each DAC (DAC0
and DAC1).
Please refer to the Section 7.5 “Enable Configuration Bit (High-Voltage)” and Section 7.6 “Disable
Configuration Bit (High-Voltage)” commands for
operation.
Note:
Dependent on the state of the DLx:CLx configuration
bits, WiperLock technology prevents the serial
commands from the following actions on the DACx
registers and bits:
• Writing to the specified volatile DACx Register
memory location
• Writing to the specified nonvolatile DACx Register
memory location
• Writing to the specified volatile DACx
configuration bits
• Writing to the specified nonvolatile DACx
configuration bits
4.2.6.1
POR/BOR Operation when
WiperLock Technology Enabled
The WiperLock Technology state is not affected by a
POR/BOR event. A POR/BOR event will load the
Volatile DAC0 (DAC1) register values with the
Nonvolatile DAC0 (DAC1) register values.
4.2.7
Each pair of these configuration bits control one of four
modes. These modes are shown in Table 4-4. The
addresses for the configuration bits are shown in
Table 4-1.
To modify the configuration bits, the HVC pin must be
forced to the VIHH state and then receive an Enable or
Disable command on the desired pair of DAC
Register addresses.
Note:
During device communication, if the
Device Address/Command combination is
invalid or an unimplemented Address is
specified, then the MCP47FEBXX will
NACK that byte. To reset the I2C state
machine, the I2C communication must
detect a Start bit.
To modify the CL0 bit, the Enable or Disable command specifies address 00h,
while to modify the DL0 bit, the Enable or
Disable command specifies address 10h.
I2C SLAVE ADDRESS WRITE
PROTECT
The MCP47FEBXX device’s I2C Slave Address is
stored in the EEPROM memory. This allows the
address to be modified to the applications requirement.
To ensure that the I2C Slave Address is not
unintentionally modified, the memory has a high
voltage write protect bit. This configurations bit is
shown in Table 4-3.
Note:
To modify the SALCK bit, the Enable or
Disable command specifies address 1Ah.
TABLE 4-3:
SALCK FUNCTIONAL
DESCRIPTION
SALCK Operation
The nonvolatile I2C™ Slave Address bits
(ADD6:ADD0) are locked
0
The nonvolatile I2C Slave Address bits
(ADD6:ADD0) are unlocked
WIPERLOCK TECHNOLOGY CONFIGURATION BITS FUNCTIONAL DESCRIPTION
DLx:CLx (2)
TABLE 4-4:
1
Volatile
Nonvolatile
11
Locked
10
Locked
01
Register / Bits
DACx
00
Note 1:
2:
DACx Configuration (1)
Comments
Volatile
Nonvolatile
Locked
Locked
Locked
All DACx registers are locked
Locked
Unlocked
Locked
All DACx registers are locked except volatile DACx
Configuration registers.
This allows operation of power-down modes
Unlocked
Locked
Unlocked
Locked
Volatile DACx registers unlocked, nonvolatile DACx
registers locked
Unlocked
Unlocked
Unlocked
Unlocked
All DACx registers are unlocked
DAC Configuration bits include Voltage Reference Control bits (VRxB:VRxA), Power-Down Control bits
(PDxB:PDxA), and Output Gain bits (Gx).
The state of these configuration bits (DLx:CLx) are reflected in WLxB:WLxA bits as shown in Register 4-6.
2015 Microchip Technology Inc.
DS20005375A-page 35
MCP47FEBXX
4.2.8
DEVICE REGISTERS
Register 4-1 shows the format of the DAC Output Value
registers for both the volatile memory locations and the
nonvolatile memory locations. These registers will be
either 8 bits, 10 bits, or 12 bits wide. The values are
right justified.
REGISTER 4-1:
12-bit
DAC0 AND DAC1 REGISTERS (VOLATILE AND NONVOLATILE)
U-0
U-0
U-0
U-0
—
—
—
—
D11
D10
(1)
(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
10-bit
—
—
—
—
—
—
8-bit
—
—
—
—
—(1)
—(1)
D09
D08
D07
D06
D05
D04
D03
D02
D01
D00
D09
D08
D07
D06
D05
D04
D03
D02
D01
D00
—(1)
—(1)
D07
D06
D05
D04
D03
D02
D01
D00
bit 15
bit 0
Legend:
R = Readable bit
-n = Value at POR
= 12-bit device
12-bit
10-bit
W = Writable bit
‘1’ = Bit is set
= 10-bit device
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
= 8-bit device
8-bit
bit 15-12 bit 15-10 bit 15-8
Unimplemented: Read as ‘0’
bit 11-0
—
—
D11-D00: DAC Output value - 12-bit devices
FFFh = Full-Scale output value
7FFh = Mid-Scale output value
000h =Zero-Scale output value
—
bit 9-0
—
D09-D00: DAC Output value - 10-bit devices
3FFh = Full-Scale output value
1FFh = Mid-Scale output value
000h =Zero-Scale output value
—
—
bit 7-0
D07-D00: DAC Output value - 8-bit devices
FFh = Full-Scale output value
7Fh = Mid-Scale output value
000h =Zero-Scale output value
Note 1:
Unimplemented bit, read as ‘0’.
DS20005375A-page 36
x = Bit is unknown
2015 Microchip Technology Inc.
MCP47FEBXX
Register 4-2 shows the format of the Voltage Reference Control Register. Each DAC has two bits to control the source of the voltage reference of the DAC. This
register is for both the volatile memory locations and
the nonvolatile memory locations. The width of this register is 2 times the number of DACs for the device.
REGISTER 4-2:
VOLTAGE REFERENCE (VREF) CONTROL REGISTER (VOLATILE
AND NONVOLATILE) (ADDRESSES 08h AND 18h)
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
Single
—
—
—
—
—
—
—
—
—
—
—
—
Dual
—
—
—
—
—
—
—
—
—
—
—
—
R/W-0 R/W-0 R/W-0 R/W-0
—(1)
—(1)
VR0B VR0A
VR1B VR1A VR0B VR0A
bit 15
bit 0
Legend:
R = Readable bit
W = Writable bit
-n = Value at POR
‘1’ = Bit is set
= Single-channel device
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
= Dual-channel device
x = Bit is unknown
Single
Dual
bit 15-2
bit 15-4
Unimplemented: Read as ‘0’
bit 1-0
bit 3-0
VRxB-VRxA: DAC Voltage Reference Control bits
11 = VREF pin (Buffered); VREF buffer enabled.
10 = VREF pin (Unbuffered); VREF buffer disabled.
01 = Internal Band Gap (1.22V typical); VREF buffer enabled. VREF voltage driven when
powered-down.
00 = VDD (Unbuffered); VREF buffer disabled. Use this state with Power-down bits for lowest
current.
Note 1:
Unimplemented bit, read as ‘0’.
2015 Microchip Technology Inc.
DS20005375A-page 37
MCP47FEBXX
Register 4-3 shows the format of the Power-Down
Control Register. Each DAC has two bits to control the
Power-Down state of the DAC. This register is for both
the volatile memory locations and the nonvolatile memory locations. The width of this register is 2 times the
number of DACs for the device.
REGISTER 4-3:
POWER-DOWN CONTROL REGISTER (VOLATILE AND NONVOLATILE)
(ADDRESSES 09h, 19h)
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
Single
—
—
—
—
—
—
—
—
—
—
—
—
—(1)
Dual
—
—
—
—
—
—
—
—
—
—
—
—
PB1B PB1A PB0B PB0A
R/W-0 R/W-0 R/W-0 R/W-0
—(1)
PB0B PB0A
bit 15
bit 0
Legend:
R = Readable bit
W = Writable bit
-n = Value at POR
‘1’ = Bit is set
= Single-channel device
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
= Dual-channel device
x = Bit is unknown
Single
Dual
bit 15-2
bit 15-4
Unimplemented: Read as ‘0’
bit 1-0
bit 3-0
PBxB-PBxA: DAC Power-Down Control bits(2)
11 = Powered Down - VOUT is open circuit.
10 = Powered Down - VOUT is loaded with a 100 k resistor to ground.
01 = Powered Down - VOUT is loaded with a 1 k resistor to ground.
00 = Normal Operation (Not powered-down).
Note 1:
2:
Unimplemented bit, read as ‘0’.
See Table 5-5 and Figure 5-10 for more details.
DS20005375A-page 38
2015 Microchip Technology Inc.
MCP47FEBXX
Register 4-4 shows the format of the Gain Control and
System Status Register. Each DAC has one bit to control the gain of the DAC and three Status bits. This register is for both the volatile memory locations and the
nonvolatile memory locations.
REGISTER 4-4:
U-0
U-0
U-0
GAIN CONTROL AND SYSTEM STATUS REGISTER (VOLATILE) (ADDRESS 0Ah)
U-0
U-0
U-0
Single
—
—
—
—
—
—
Dual
—
—
—
—
—
—
R/W-0 R/W-0 R/C-1
(1)
—
G1
R/W-0
U-0
U-0
U-0
U-0
U-0
U-0
G0
POR EEWA
—
—
—
—
—
—
G0
POR EEWA
—
—
—
—
—
—
bit 15
bit 0
Legend:
R = Readable bit
W = Writable bit
-n = Value at POR
‘1’ = Bit is set
= Single-channel device
C = Clear-able bit
‘0’ = Bit is cleared
= Dual-channel device
U = Unimplemented bit, read as ‘0’
x = Bit is unknown
Single
Dual
bit 15-9
bit 15-10 Unimplemented: Read as ‘0’
—
bit 9
G1: DAC1 Output Driver Gain control bits (Dual-Channel Device only)
1 = 2x Gain. Not applicable when VDD is used as VRL.
0 = 1x Gain.
bit 8
bit 8
G0: DAC0 Output Driver Gain control bits
1 = 2x Gain. Not applicable when VDD is used as VRL.
0 = 1x Gain.
bit 7
bit 7
POR: Power-on Reset (Brown-out Reset) Status bit
This bit indicates if a Power-on Reset (POR) or Brown-out Reset (BOR) event has
occurred since the last read command of this register. Reading this register clears the
state of the POR Status bit.
1 = A POR (BOR) event occurred since the last read of this register. Reading this register clears
this bit.
0 = A POR (BOR) event has not occurred since the last read of this register.
bit 6
bit 6
EEWA: EEPROM Write Active Status bit
This bit indicates if the EEPROM Write Cycle is occurring
1 = An EEPROM Write Cycle is currently occurring. Only serial commands to the volatile memory are allowed.
0 = An EEPROM Write Cycle is NOT currently occurring.
bit 5-0
bit 5-0
Unimplemented: Read as ‘0’
Note 1:
Unimplemented bit, read as ‘0’.
2015 Microchip Technology Inc.
DS20005375A-page 39
MCP47FEBXX
Register 4-5 shows the format of the Nonvolatile Gain
Control and Slave Address Register. Each DAC has
one bit to control the gain of the DAC. I2C devices also
have eight bits that are the I2C Slave Address and the
status of the I2C Address Lock bit.
REGISTER 4-5:
U-0
U-0
U-0
GAIN CONTROL AND SLAVE ADDRESS REGISTER (NONVOLATILE) (ADDRESS 1Ah)
U-0
U-0
Single
—
—
—
—
—
Dual
—
—
—
—
—
R/W-0 R/W-0
(1)
—
G1
R/W-0
R/W-0
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
G0
ADLCK EEWA ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0
G0
ADLCK EEWA ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0
bit 15
bit 0
Legend:
R = Readable bit
W = Writable bit
-n = Value at POR
‘1’ = Bit is set
= Single-channel device
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
= Dual-channel device
x = Bit is unknown
Single
Dual
bit 15-9
bit 15-10 Unimplemented: Read as ‘0’
—
bit 9
G1: DAC1 Output Driver Gain control bits (Dual-Channel Device only)(2)
1 = 2x Gain. Not applicable when VDD is used as VRL.
0 = 1x Gain.
bit 8
bit 8
G0: DAC0 Output Driver Gain control bits(3)
1 = 2x Gain. Not applicable when VDD is used as VRL.
0 = 1x Gain.
bit 7
bit 7
ADLCK: I2C Address Lock Status bit (Read-Only bit; reflects the state of the SALCK configuration bit).
1 = I2C Slave Address is Locked (requires HV command to disable, so I2C address can be
changed)
0 = I2C Slave Address is NOT Lock, the nonvolatile I2C slave address can be changed.
bit 6-0
bit 6-0
ADD6-ADD0: I2C 7-bit Slave Address Bits.
Note 1:
2:
3:
Unimplemented bit, read as ‘0’.
If VR1B:VR1A = ‘00’; the device uses a gain of 1 only, regardless of the state of this bit (G1).
If VR0B:VR0A = ‘00’; the device uses a gain of 1 only, regardless of the state of this bit (G0).
DS20005375A-page 40
2015 Microchip Technology Inc.
MCP47FEBXX
Register 4-6 shows the format of the DAC WiperLock
Technology Status Register. The width of this register
is 2 times the number of DACs for the device.
REGISTER 4-6:
Single
Dual
DAC WIPERLOCK TECHNOLOGY STATUS REGISTER (VOLATILE) (ADDRESS 0BH)
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
R-0(2)
R-0(2)
R-0(2)
R-0(2)
—
—
—
—
—
—
—
—
—
—
—
—
—(1)
—(1)
WL0B WL0A
—
—
—
—
—
—
—
—
—
—
—
—
WL1B WL1A WL0B WL0A
bit 15
bit 0
Legend:
R = Readable bit
W = Writable bit
-n = Value at POR
‘1’ = Bit is set
= Single-channel device
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
= Dual-channel device
x = Bit is unknown
Single
Dual
bit 15-2
bit 15-4
Unimplemented: Read as ‘0’
bit 1-0
bit 3-0
WLxB-WLxA: WiperLock Technology Status bits: These bits reflect the state of the DLx:CLx
nonvolatile configuration bits
11 = DAC wiper and DAC Configuration (volatile and nonvolatile registers) are locked
(DLx = CLx = Enabled)
10 = DAC wiper (volatile and nonvolatile) and DAC Configuration (nonvolatile registers) are
locked
(DLx = Enabled; CLx = Disabled).
01 = DAC wiper (nonvolatile) and DAC Configuration (nonvolatile registers) are locked
(DLx = Disabled; CLx = Enabled)
00 = DAC wiper and DAC Configuration are unlocked (DLx = CLx = Disabled).
Note 1:
2:
Unimplemented bit, read as ‘0’.
POR Value dependent on the programmed values of the DLx:CLx configuration bits. The devices are
shipped with a default DLx:CLx configuration bit state of ‘0’.
2015 Microchip Technology Inc.
DS20005375A-page 41
MCP47FEBXX
NOTES:
DS20005375A-page 42
2015 Microchip Technology Inc.
MCP47FEBXX
5.0
DAC CIRCUITRY
The functional blocks of the DAC include:
•
•
•
•
•
•
The Digital to Analog Converter circuitry converts a digital
value into its analog representation. The description
describes the functional operation of the device.
The DAC Circuit uses a resistor ladder implementation.
Devices have up to two DACs.
Figure 5-1 shows the functional block diagram for the
MCP47FEBXX DAC circuitry.
Power-Down
Operation
PD1:PD0 and
VREF1:VREF0
VDD
Voltage
Reference
Selection
Resistor Ladder
Voltage Reference Selection
Output Buffer/VOUT Operation
Internal Band Gap (as a voltage reference)
Latch Pin (LAT)
Power-Down Operation
VREF
+
-
VDD
VDD
VREF1:VREF0
PD1:PD0 and BGEN
Band Gap
(1.22V typical)
VREF1:VREF0
PD1:PD0
VDD
A (RL)
RS(2n)
DAC
Output
Selection
Power-Down
Operation
PD1:PD0
VW
VOUT
+
RS(2n - 1)
-
Output Buffer/VOUT
Operation
RRL RS(2n - 3)
(~140 k)
100 k
PD1:PD0
Gain
(1x or 2x)
RS(2n - 2)
1 k
VRL
Internal Band Gap
Power-Down
Operation
DAC Register Value
V W = ---------------------------------------------------------------------- V RL
# Resistor in Resistor Ladder
RS(2)
Where:
# Resistors in Resistor Ladder = 256 (MCP47FEB0X)
Resistor
Ladder
1024 (MCP47FEB1X)
RS(1)
4096 (MCP47FEB2X)
B
FIGURE 5-1:
MCP47FEBXX DAC Module Block Diagram.
2015 Microchip Technology Inc.
DS20005375A-page 43
MCP47FEBXX
5.1
Resistor Ladder
PD1:PD0
The Resistor Ladder is a digital potentiometer with the
B Terminal internally grounded and the A Terminal
connected to the selected reference voltage (see
Figure 5-2). The volatile DAC register controls the
wiper position. The wiper voltage (VW) is proportional to
the DAC register value divided by the number of resistor elements (RS) in the ladder (256, 1024 or 4096)
related to the VRL voltage.
The output of the resistor network will drive the input of
an output buffer.
VRL
DAC
Register
RS(2n)
2n - 1
RW (1)
RS(2n - 1)
RRL
2n - 2
RW (1)
RS(2n - 2)
The Resistor Network is made up of these three parts:
VW
• Resistor Ladder (string of RS elements)
• Wiper switches
• DAC Register decode
The resistor ladder (RRL) has a typical impedance of
approximately 140 k. This resistor ladder resistance
(RRL) may vary from device to device up to ±20%.
Since this is a voltage divider configuration, the actual
RRL resistance does not affect the output given a fixed
voltage at VRL.
Equation 5-1 shows the calculation for the step
resistance.
Note:
The maximum wiper position is 2n – 1,
while the number of resistors in the
resistor ladder is 2n. This means that
when the DAC register is at full scale,
there is one resistor element (RS)
between the wiper and the VRL voltage.
If the unbuffered VREF pin is used as the VRL voltage
source, this voltage source should have a low output
impedance.
When the DAC is powered-down, the resistor ladder is
disconnected from the selected reference voltage.
DS20005375A-page 44
1
RW
RS(1)
(1)
0
(1)
RW
Analog Mux
DAC Register Value
V W = ---------------------------------------------------------------------- V RL
# Resistor in Resistor Ladder
Where:
# Resistors in R-Ladder = 256 (MCP47FEB0X)
1024 (MCP47FEB1X)
4096 (MCP47FEB2X)
Note 1: The analog switch resistance (RW)
does not affect performance due to the
voltage divider configuration.
FIGURE 5-2:
Block Diagram.
Resistor Ladder Model
EQUATION 5-1:
RS CALCULATION
RRL
R S = ------------ 256
8-bit Device
R RL
R S = --------------- 1024
10-bit Device
R RL
R S = --------------- 4096
12-bit Device
2015 Microchip Technology Inc.
MCP47FEBXX
Voltage Reference Selection
The resistor ladder has up to four sources for the reference voltage. Two user control bits (VREF1:VREF0)
are used to control the selection, with the selection connected to the VRL node (see Figures 5-3 and 5-4). The
four voltage source options for the Resistor Ladder are:
1.
2.
3.
4.
VDD pin voltage
Internal Voltage Reference (VBG)
VREF pin voltage unbuffered
VREF pin voltage internally buffered
The selection of the voltage is specified with the volatile
VREF1:VREF0 configuration bits (see Register 4-2).
There are nonvolatile and volatile VREF1:VREF0
configuration bits. On a POR/BOR event, the state of the
nonvolatile VREF1:VREF0 configuration bits is latched
into the volatile VREF1:VREF0 configuration bits.
VREF1:VREF0
VREF
VDD
Band Gap
Reference
Selection
5.2
VRL
Buffer
FIGURE 5-3:
Resistor Ladder Reference
Voltage Selection Block Diagram.
VDD
PD1:PD0 and
VREF1:VREF0
When the user selects the VDD as reference, the VREF
pin voltage is not connected to the resistor ladder.
VREF
+
VRL
-
If the VREF pin is selected, then one needs to select
between the buffered or unbuffered mode.
5.2.1
UNBUFFERED MODE
VDD
The VREF pin voltage may be from VSS to VDD.
Note 1: The voltage source should have a low
output impedance. If the voltage source
has a high output impedance, then the
voltage on the VREF’s pin would be lower
than expected. The resistor ladder has a
typical impedance of 140 k and a typical capacitance of 29 pF.
2: If the VREF pin is tied to the VDD voltage, VDD mode (VREF1:VREF0 = ‘00’)
is recommended.
5.2.2
BUFFERED MODE
The VREF pin voltage may be from 0.01V to VDD 0.04V. The input buffer (amplifier) provides low offset
voltage, low noise, and a very high input impedance,
with only minor limitations on the input range and frequency response.
Note 1: Any variation or noises on the reference
source can directly affect the DAC output.
The reference voltage needs to be as
clean as possible for accurate DAC
performance.
2: If the VREF pin is tied to the VDD voltage, VDD mode (VREF1:VREF0 = ‘00’)
is recommended.
2015 Microchip Technology Inc.
VDD
VREF1:VREF0
VREF1:VREF0
PD1:PD0
and BGEN
Band Gap (1)
(1.22V typical)
Note 1: The Band Gap voltage (VBG) is 1.22V
typical. The band gap output goes through
the buffer with a 2x gain to create the VRL
voltage. See Section 5.4 “Internal Band
Gap” for addition information on the band
gap circuit.
FIGURE 5-4:
Reference Voltage Selection
Implementation Block Diagram.
5.2.3
BANDGAP MODE
If the Internal Band Gap is selected, then the external
VREF pin should not be driven and only use
high-impedance loads. Decoupling capacitors are
recommended for optimal operation.
The band gap output is buffered, but the internal
switches limit the current that the output should source
to the VREF pin. The resistor ladder buffer is used to
drive the Band Gap voltage for the cases of multiple
DAC outputs. This ensures that the resistor ladders are
always properly sourced when the band gap is selected.
DS20005375A-page 45
MCP47FEBXX
5.3
Output Buffer/VOUT Operation
TABLE 5-1:
The Output Driver buffers the wiper voltage (VW) of the
Resistor Ladder.
The DAC output is buffered with a low power and
precision output amplifier (op amp). This amplifier
provides a rail-to-rail output with low offset voltage and low
noise. The amplifier’s output can drive the resistive and
high-capacitive loads without oscillation. The amplifier
provides a maximum load current which is enough for
most programmable voltage reference applications. Refer
to Section 1.0 “Electrical Characteristics” for the
specifications of the output amplifier.
Note:
The load resistance must keep higher than
5 k for the stable and expected analog
output (to meet electrical specifications).
Figure 5-5 shows a block diagram of the output driver
circuit.
OUTPUT DRIVER GAIN
Gain Bit
Gain
0
1
1
2
5.3.1
Comment
Limits VREF pin voltages
relative to device VDD voltage.
PROGRAMMABLE GAIN
The amplifier’s gain is controlled by the Gain (G)
configuration bit (see Register 4-5) and the VRL reference selection. When the VRL reference selection is the
device’s VDD voltage, the G bit is ignored and a gain
of 1 is used.
The volatile G bit value can be modified by:
• POR event
• BOR event
• I2C Write commands
• I2C General Call Reset command
The user can select the output gain of the output
amplifier. Gain options are:
a)
b)
Gain of 1, with either VDD or VREF pin used as
reference voltage.
Gain of 2, only when VREF pin or Internal Band
Gap is used as reference voltage. The VREF pin
voltage should be limited to VDD/2.
Power-down logic also controls the output buffer operation (see Section 5.6 “Power-Down Operation” for
additional information on Power-down). In any of the
three Power-Down modes, the op amp is powereddown and its output becomes a high impedance to the
VOUT pin.
Table 5-1 shows the gain bit operation. When the
reference voltage selection (VRL) is the device’s VDD
voltage, the G bit is ignored and a gain of 1 is used.
VDD
PD1:PD0
VW
VOUT
+
-
1 k
100 k
PD1:PD0
Gain(1)
Note 1: Gain options are 1x and 2x.
FIGURE 5-5:
DS20005375A-page 46
Output Driver Block Diagram.
2015 Microchip Technology Inc.
MCP47FEBXX
5.3.2
OUTPUT VOLTAGE
The volatile DAC Register values along with the
device’s configuration bits control the analog VOUT voltage. The volatile DAC Register’s value is unsigned
binary. The formula for the output voltage is given in
Equation 5-2. Table 5-3 shows examples of volatile
DAC register values and the corresponding theoretical
VOUT voltage for the MCP47FEBXX devices.
EQUATION 5-2:
CALCULATING OUTPUT
VOLTAGE (VOUT)
V RL DAC Register Value
VOUT = ---------------------------------------------------------------------- Gain
# Resistor in Resistor Ladder
5.3.3
STEP VOLTAGE (VS)
The Step Voltage is dependent on the device resolution
and the calculated output voltage range. One LSb is
defined as the ideal voltage difference between two
successive codes. The step voltage can easily be calculated by using Equation 5-3 (DAC Register Value is
equal to 1). Theoretical Step Voltages are shown in
Table 5-2 for several VREF voltages.
EQUATION 5-3:
VS CALCULATION
V RL
VS = ---------------------------------------------------------------------- Gain
# Resistor in Resistor Ladder
Where:
Where:
# Resistors in R-Ladder = 4096 (MCP47FEB2X)
# Resistors in R-Ladder = 4096 (12-bit)
1024 (10-bit)
1024 (MCP47FEB1X)
256 (8-bit)
256 (MCP47FEB0X)
Note:
When Gain = 2 (VRL = VREF),
if VREF > VDD / 2, the VOUT voltage will be
limited to VDD. So if VREF = VDD, then the
VOUT voltage will not change for volatile
DAC Register values mid-scale and greater,
since the op amp is at full-scale output.
The following events update the DAC register value
and therefore the analog voltage output (VOUT):
• Power-on Reset
• Brown-out Reset
• I2C Write Command, Falling edge of the acknowledge pulse of the last write command byte.
• I2C General Call Reset command, Output is
updated with POR data (EEPROM).
TABLE 5-2:
THEORETICAL STEP
VOLTAGE (VS) (1)
VREF
5.0
2.7
1.8
1.5
1.0
1.22mV
659uV
439uV
366uV
244uV
12-bit
977uV
10-bit
VS 4.88mV 2.64mV 1.76mV 1.46mV
19.5mV 10.5mV 7.03mV 5.86mV 3.91mV 8-bit
Note 1: When Gain = 1x, VFS = VRL, and VZS = 0V.
Then the VOUT voltage will start driving to the new value
after the event has occurred.
2015 Microchip Technology Inc.
DS20005375A-page 47
MCP47FEBXX
5.3.4
OUTPUT SLEW RATE
Figure 5-6 shows an example of the slew rate of the
VOUT pin. The slew rate can be affected by the characteristics of the circuit connected to the VOUT pin.
VOUT(B)
DACx = A
DACx= B
Time
V OUT B – V OUT A
Slew Rate = -------------------------------------------------T
FIGURE 5-6:
5.3.4.1
VOUT pin Slew Rate.
Small Capacitive Load
With a small capacitive load, the output buffer’s current
is not affected by the capacitive load (CL). But still, the
VOUT pin’s voltage is not a step transition from one output value (DAC register value) to the next output value.
The change of the VOUT voltage is limited by the output
buffer’s characteristics, so the VOUT pin voltage will
have a slope from the old voltage to the new voltage.
This slope is fixed for the output buffer, and is referred
to as the buffer slew rate (SRBUF).
5.3.4.2
DRIVING RESISTIVE AND
CAPACITIVE LOADS
The VOUT pin can drive up to 100 pF of capacitive load
in parallel with a 5 k resistive load (to meet electrical
specifications). A VOUT vs. Resistive Load characterization graph can be seen in the Char Data for this
device (DS20005378).
VOUT drops slowly as the load resistance decreases
after about 3.5 k. It is recommended to use a load
with RL greater than 5 k.
VOUT
VOUT(A)
5.3.5
Driving large capacitive loads can cause stability
problems for voltage feedback op amps. As the load
capacitance increases, the feedback loop’s phase
margin decreases and the closed-loop bandwidth is
reduced. This produces gain peaking in the frequency
response with overshoot and ringing in the step
response. That is, since the VOUT pin’s voltage does
not quickly follow the buffer’s input voltage (due to the
large capacitive load), the output buffer will overshoot
the desired target voltage. Once the driver detects this
overshoot, it compensates by forcing it to a voltage
below the target. This causes voltage ringing on the
VOUT pin.
So, when driving large capacitive loads with the output
buffer, a small series resistor (RISO) at the output (see
Figure 5-7) improves the output buffer’s stability
(feedback loop’s phase margin) by making the output
load resistive at higher frequencies. The bandwidth will
be generally lower than the bandwidth with no
capacitive load.
Large Capacitive Load
With a larger capacitive load, the slew rate is
determined by two factors:
• The output buffer’s short-circuit current (ISC)
• The VOUT pin’s external load
IOUT cannot exceed the output buffer’s short-circuit current (ISC), which fixes the output buffer slew rate
(SRBUF). The voltage on the capacitive load (CL), VCL,
changes at a rate proportional to IOUT, which fixes a
capacitive load slew rate (SRCL).
So the VCL voltage slew rate is limited to the slower of
the output buffer’s internally set slew rate (SRBUF) and
the capacitive load slew rate (SRCL).
VW
Op
Amp
VOUT
VCL
RISO
RL
CL
FIGURE 5-7:
Circuit to Stabilize Output
Buffer for Large Capacitive Loads (CL).
The RISO resistor value for your circuit needs to be
selected. The resulting frequency response peaking
and step response overshoot for this RISO resistor
value should be verified on the bench. Modify the
RISO’s resistance value until the output characteristics
meet your requirements.
A method to evaluate the system’s performance is to
inject a step voltage on the VREF pin and observe the
VOUT pin’s characteristics.
Note:
DS20005375A-page 48
Additional insight into circuit design for
driving capacitive loads can be found in
AN884 – “Driving Capacitive Loads With
Op Amps” (DS00000884).
2015 Microchip Technology Inc.
MCP47FEBXX
TABLE 5-3:
Device
DAC INPUT CODE VS. CALCULATED ANALOG OUTPUT (VOUT) (VDD = 5.0V)
Volatile DAC
Register Value
1111 1111 1111
VRL
(1)
LSb
Gain
Selection
Equation
µV
5.0V
5.0V/4096
1,220.7
1x
VRL (4095/4096) 1
4.998779
2.5V
2.5V/4096
610.4
1x
VRL (4095/4096) 1
2.499390
(2)
MCP47FEB2X (12-bit)
0011 1111 1111
5.0V
5.0V/4096
1,220.7
2.5V
2.5V/4096
610.4
MCP47FEB1X (10-bit)
11 1111 1111
01 1111 1111
00 1111 1111
00 0000 0000
MCP47FEB0X (8-bit)
1111 1111
0111 1111
0011 1111
0000 0000
Note 1:
2:
3:
V
VRL (4095/4096) 2)
4.998779
VRL (2047/4096) 1)
2.498779
1x
VRL (2047/4096) 1)
1.249390
2x(2)
VRL (2047/4096) 2)
2.498779
5.0V
5.0V/4096
1,220.7
1x
VRL (1023/4096) 1)
1.248779
2.5V
2.5V/4096
610.4
1x
VRL (1023/4096) 1)
0.624390
VRL (1023/4096) 2)
1.248779
2x
0000 0000 0000
(2)
Equation
1x
2x
0111 1111 1111
VOUT(3)
5.0V
5.0V/4096
1,220.7
2.5V
2.5V/4096
610.4
(2)
1x
VRL (0/4096) * 1)
1x
VRL (0/4096) * 1)
0
2x(2)
VRL (0/4096) * 2)
0
0
5.0V
5.0V/1024
4,882.8
1x
VRL (1023/1024) 1
4.995117
2.5V
2.5V/1024
2,441.4
1x
VRL (1023/1024) 1
2.497559
2x(2)
5.0V
5.0V/1024
4,882.8
2.5V
2.5V/1024
2,441.4
VRL (1023/1024) 2
4.995117
1x
VRL (511/1024) 1
2.495117
1x
VRL (511/1024) 1
1.247559
2x(2)
VRL (511/1024) 2
2.495117
VRL (255/1024) 1
1.245117
5.0V
5.0V/1024
4,882.8
1x
2.5V
2.5V/1024
2,441.4
1x
VRL (255/1024) 1
0.622559
2x(2)
VRL (255/1024) 2
1.245117
5.0V
5.0V/1024
4,882.8
2.5V
2.5V/1024
2,441.4
1x
VRL (0/1024) 1
0
1x
VRL (0/1024) 1
0
2x(2)
VRL (0/1024) 1
0
5.0V
5.0V/256
19,531.3
1x
VRL (255/256) 1
4.980469
2.5V
2.5V/256
9,765.6
1x
VRL (255/256) 1
2.490234
2x(2)
VRL (255/256) 2
4.980469
1x
VRL (127/256) 1
2.480469
5.0V
5.0V/256
19,531.3
2.5V
2.5V/256
9,765.6
1x
VRL (127/256) 1
1.240234
2x(2)
VRL (127/256) 2
2.480469
5.0V
5.0V/256
19,531.3
1x
VRL (63/256) 1
1.230469
2.5V
2.5V/256
9,765.6
1x
VRL (63/256) 1
0.615234
2x(2)
VRL (63/256) 2
1.230469
1x
VRL (0/256) 1
0
1x
VRL (0/256) 1
0
2x(2)
VRL (0/256) 2
0
5.0V
5.0V/256
19,531.3
2.5V
2.5V/256
9,765.6
VRL is the resistor ladder’s reference voltage. It is independent of VREF1:VREF0 selection.
Gain selection of 2x (Gx = ‘1‘) requires voltage reference source to come from VREF pin
(VREF1:VREF0 = ‘10‘ or ‘11’) and requires VREF pin voltage (or VRL) ≤ VDD/2 or from the internal band
gap (VREF1:VREF0 = ‘01’).
These theoretical calculations do not take into account the Offset, Gain and nonlinearity errors.
2015 Microchip Technology Inc.
DS20005375A-page 49
MCP47FEBXX
5.4
Internal Band Gap
The internal band gap is designed to drive the Resistor
Ladder Buffer.
The resistance of a resistor ladder (RRL) is targeted to
be 140 k (40 k), which means a minimum resistance of 100 k.
The band gap selection can be used across the VDD
voltages while maximizing the VOUT voltage ranges.
For VDD voltages below the 2 Gain VBG voltage, the
output for the upper codes will be clipped to the VDD
voltage. Table 5-4 shows the maximum DAC register
code given device VDD and Gain bit setting.
5.5
2.7
2.0(4)
DAC Gain
VDD
TABLE 5-4:
VOUT USING BAND GAP
Max DAC Code (1)
12bit
10-bit 8-bit
1
FFFh
3FFh
2
FFFh
3FFh
1
FFFh
3FFh
Comment
FFh VOUT(max) = 2.44V(3)
FFh VOUT(max) = 4.88V(3)
FFh VOUT(max) = 2.44V(3)
2
8DAh
236h
8Dh ~ 0 to 55% range
1
D1Dh
347h
D1h ~ 0 to 82% range
68Eh
1A3h
68h
2(2)
Note 1:
2:
3:
4:
~ 0 to 41% range
Without the VOUT pin voltage being clipped.
Recommended to use Gain = 1 setting.
When VBG = 1.22V typical.
Band gap performance achieves full
performance starting from a VDD of 2.0V.
DS20005375A-page 50
2015 Microchip Technology Inc.
MCP47FEBXX
5.5
Latch Pin (LAT)
The Latch pin controls when the volatile DAC Register
value is transferred to the DAC wiper. This is useful for
applications that need to synchronize the wiper(s)
updates to an external event, such as zero crossing or
updates to the other wipers on the device. The LAT pin
is asynchronous to the serial interface operation.
Serial Shift Reg
Register Address
Write Command
16 Clocks
Vol. DAC Register x
LAT
Transfer
SYNC
Data
(internal signal)
DAC wiper x
When the LAT pin is high, transfers from the volatile DAC
register to the DAC wiper are inhibited. The volatile DAC
register value(s) can be continued to be updated.
When the LAT pin is low, the volatile DAC register value
is transferred to the DAC wiper.
Note:
This allows both the volatile DAC0 and
DAC1 Registers to be updated while the
LAT pin is high, and to have outputs synchronously updated as the LAT pin is
driven low.
Figure 5-8 shows the interaction of the LAT pin and the
loading of the DAC wiper x (from the volatile DAC Register x). The transfers are level driven. If the LAT pin is
held low, the corresponding DAC wiper is updated as
soon as the volatile DAC Register value is updated.
LAT SYNC
Transfer
Data
Comment
1
1
0
No Transfer
1
0
0
No Transfer
0
1
1
Vol. DAC Register x DAC wiper x
0
0
0
No Transfer
FIGURE 5-8:
LAT and DAC Interaction.
The LAT pin allows the DAC wiper to be updated to an
external event as well as have multiple DAC channels/devices update at a common event.
Since the DAC wiper x is updated from the Volatile
DAC Register x, all DACs that are associated with a
given LAT pin can be updated synchronously.
If the application does not require synchronization, then
this signal should be tied low.
Figure 5-9 shows two cases of using the LAT pin to
control when the wiper register is updated relative to
the value of a sine wave signal.
Case 1: Zero Crossing of Sine Wave to update volatile DAC0 register (using LAT pin)
Case 2: Fixed point Crossing of Sine Wave to update volatile DAC0 register (using LAT pin)
Indicates where LAT pin pulses active (volatile DAC0 register updated)
FIGURE 5-9:
Example use of LAT pin operation.
2015 Microchip Technology Inc.
DS20005375A-page 51
MCP47FEBXX
Power-Down Operation
To allow the application to conserve power when the
DAC operation is not required, three power-down
modes are available. The Power-Down configuration
bits (PD1:PD0) control the power-down operation
(Figure 5-10 and Table 5-5). On devices with multiple
DACs, each DACs power-down mode is individually
controllable. All power-down modes do the following:
• Turn off most the DAC module’s internal circuits
(output op amp, resistor ladder,...)
• Op amp output becomes high-impedance to the
VOUT pin
• Disconnects resistor ladder from reference
voltage (VRL)
• Retains the value of the volatile DAC register and
configuration bits, and the nonvolatile (EEPROM)
DAC register and configuration bits
VW
V OUT
+
PD1:PD0
1k
(1)
Note 1: Gain options are 1x and 2x.
• VOUT pin is switched to one of two resistive pulldowns (See Table 5-5)
- 100 k (typical)
- 1 k (typical)
• Op amp is powered-down and the VOUT pin is
high-impedance.
There is a delay (TPDE) between the PD1:PD0 bits
changing from ‘00’ to either ‘01’, ‘10’ or ‘11’ and the op
amp no longer driving the VOUT output and the pulldown resistors sinking current.
In any of the power-down modes where the VOUT pin is
not externally connected (sinking or sourcing current),
the power-down current will typically be ~650 nA for a
single-DAC device. As the number of DACs increases,
the device’s power-down current will also increase.
The power-down bits are modified by using a Write
command to the volatile Power-Down register, or a POR
event which transfers the nonvolatile Power-Down register to the volatile Power-Down register.
2C
Section 7.0 “Device Commands” describes the I
commands for writing the power-down bits. The
commands that can update the volatile PD1:PD0 bits are:
Write Command (Normal and High-Voltage)
Read Command (Normal and High-Voltage)
Enable Configuration Bit (High-Voltage)
Disable Configuration Bit (High-Voltage)
General Call Reset
General Call Wake-up
Note:
PD1:PD0
Gain
Depending on the selected power-down mode, the
following will occur:
•
•
•
•
•
•
V DD
100 k
5.6
FIGURE 5-10:
Diagram.
VOUT Power-Down Block
TABLE 5-5:
PD1
PD0
0
0
POWER-DOWN BITS AND
OUTPUT RESISTIVE LOAD
Function
Normal operation
0
1
1 k resistor to ground
1
0
100 k resistor to ground
1
1
Open Circuit
Table 5-6 shows the current sources for the DAC based
on the selected source of the DAC’s reference voltage
and if the device is in normal operating mode or one of
the power-down modes.
TABLE 5-6:
Device VDD
Current
Source
DAC CURRENT SOURCES
PD1:0 ‘00’,
VREF1:0 =
PD1:0 = ‘00’,
VREF1:0 =
00 01
10
11 00 01
10
11
Output
Op Amp
Y
Y
Y
Y
N
N
N
N
Resistor
Ladder
Y
Y
N (1)
Y
N
N
N (1)
N
RL Op Amp
N
Y
N
Y
N
N
N
N
Band Gap
N
Y
N
N
N
Y
N
N
Note 1:
Current is sourced from the VREF pin, not the
device VDD.
The I2C serial interface circuit is not
affected by the Power-Down mode. This
circuit remains active in order to receive
any command that might come from the
I2C master device.
DS20005375A-page 52
2015 Microchip Technology Inc.
MCP47FEBXX
5.6.1
EXITING POWER-DOWN
When the device exits the power-down mode the
following occurs:
• Disabled circuits (op amp, resistor ladder, ...) are
turned on
• Resistor ladder is connected to selected
reference voltage (VRL)
• Selected pull-down resistor is disconnected
• The VOUT output will be driven to the voltage
represented by the volatile DAC Register’s value
and configuration bits
The VOUT output signal will require time as these
circuits are powered-up and the output voltage is driven
to the specified value as determined by the volatile
DAC register and configuration bits.
Note:
Since the op amp and resistor ladder were
powered-off (0V), the op amp’s input
voltage (VW) can be considered 0V. There
is a delay (TPDD) between the PD1:PD0
bits updating to ‘00’ and the op amp driving the VOUT output. The op amp’s settling
time (from 0V) needs to be taken into
account to ensure the VOUT voltage
reflects the selected value.
The following events will change the PD1:PD0 bits to ‘00’
and therefore exit the Power-Down mode. These are:
• Any I2C write command where the PD1:PD0 bits
are ‘00’.
• I2C General Call Wake-up Command.
• I2C General Call Reset Command.
(if nonvolatile PD1:PD0 bits are ‘00’).
5.6.2
RESET COMMANDS
When the MCP47FEBXX is in the valid operating voltage, the I2C General Call Reset command will force a
Reset event. This is similar to the Power-on Reset,
except that the Reset delay timer is not started.
5.7
DAC Registers, Configuration
Bits, and Status Bits
The MCP47FEBXX devices have both volatile and
nonvolatile (EEPROM) memory. Table 4-2 shows the
volatile and nonvolatile memory and their interaction
due to a POR event.
There are five configuration bits in both the volatile and
nonvolatile memory, the DAC registers in both the
volatile and nonvolatile memory, and two volatile status
bits. The DAC registers (volatile and nonvolatile) will be
either 12 bits (MCP47FEB2X), 10 bits (MCP47FEB1X),
or 8 bits (MCP47FEB0X) wide.
When the device is first powered-up, it automatically
uploads the EEPROM memory values to the volatile
memory. The volatile memory determines the analog
output (VOUT) pin voltage. After the device is poweredup, the user can update the device memory.
The I2C interface is how this memory is read and written.
Refer to Section 6.0 “I2C Serial Interface Module”
and Section 7.0 “Device Commands” for more details
on reading and writing the device’s memory.
When the nonvolatile memory is written, the device
starts writing the EEPROM cell at the Acknowledge
pulse of the Write command.
Register 4-4 shows the operation of the device status
bits, Table 4-3 and Table 4-4 show the operation of the
device configuration bits, and Table 4-2 shows the factory default value of a POR/BOR event for the device
configuration bits.
There are two status bits. These are only in volatile
memory and give indication on the status of the device.
The POR bit indicates if the device VDD is above or
below the POR trip point. During normal operation, this
bit should be ‘1’. The RDY/BSY bit indicates if an
EEPROM write cycle is in progress. While the
RDY/BSY bit is low (during the EEPROM writing), all
commands are ignored, except for the Read command.
If the I2C interface bus does not seem to be responsive, the technique shown in Section 8.9 “Software
I2C Interface Reset Sequence” can be used to force
the I2C interface to be reset.
2015 Microchip Technology Inc.
DS20005375A-page 53
MCP47FEBXX
I2C SERIAL INTERFACE
MODULE
6.0
The MCP47FEBXX’s I2C Serial Interface Module supports the I2C serial protocol specification. This I2C
interface is a two-wire interface (clock and data).
Figure 6-1 shows a typical I2C interface connection.
2
The I C specification only defines the field types, field
lengths, timings, etc. of a frame. The frame content
defines the behavior of the device. The frame content
(Commands) for the MCP47FEBXX is defined in
Section 7.0 “Device Commands”.
An overview of the I2C protocol is available in
Section Appendix B: “I2C Serial Interface”.
MCP47FEBXX
(Slave)
SDA
6.1
POR/BOR
On a POR/BOR event, the I2C Serial Interface Module
state machine is reset, which includes that the Device’s
Memory Address pointer is forced to 00h.
SDA
The memory address is the 5-bit value that specifies
the location in the device’s memory that the specified
command will operate on.
Typical I2C Interface.
Overview
The following sections discuss some of these devicespecific characteristics.
Interface Pins (SCL and SDA)
Communication Data Rates
POR/BOR
Device Memory Address
General Call Commands
Device I2C Slave Addressing
Entering High-Speed (HS) Mode
6.2
A description on how to enter High-Speed mode is
described in Section 6.9 “Entering High-Speed (HS)
Mode”.
6.5
This sections discusses some of the specific characteristics of the MCP47FEBXX’s I2C Serial Interface Module.
This is to assist in the development of your application.
•
•
•
•
•
•
•
• Standard mode: up to 100 kHz (kbit/s)
• Fast mode: up to 400 kHz (kbit/s)
• High-Speed mode (HS mode): up to 3.4 MHz
(Mbit/s)
SCL
Other Devices
FIGURE 6-1:
Communication Data Rates
The I2C interface specifies different communication bit
rates. These are referred to as Standard, Fast or HighSpeed modes. The MCP47FEBXX supports these three
modes. The clock rates (bit rate) of these modes are:
6.4
Typical I2C™ Interface Connections
Host
Controller
(Master)
SCL
6.3
Interface Pins (SCL and SDA)
The MCP47FEBXX I2C’s module SCL pin does not
generate the serial clock since the device operates in
Slave mode. Also, the MCP47FEBXX will not stretch
the clock signal (SCL) since memory read access
occurs fast enough.
Device Memory Address
On a POR/BOR event, the Device’s Memory Address
pointer is forced to 00h.
The MCP47FEBXX retains the last “Device Memory
Address” that it has received. That is, the
MCP47FEBXX does not “corrupt” the “Device Memory
Address” after Repeated Start or Stop conditions.
6.6
General Call Commands
The General Call commands utilize the I2C
specification reserved General Call command address
and command codes. The MCP47FEBXX also implements a non-standard General Call command.
The General Call commands are
• General Call Reset
• General Call Wake-up (MCP47FEBXX defined)
The General Call Wake-up command will cause all the
MCP47FEBXX devices to exit their power-down state.
6.7
Multi-Master Systems
The MCP47FEBXX is not a Master device (generate
the interface clock), but can be used in multi-master
applications.
The MCP47FEBXX I2C’s module implements slope
control on the SDA pin output driver.
DS20005375A-page 54
2015 Microchip Technology Inc.
MCP47FEBXX
Device I2C Slave Addressing
6.8
The MCP47FEBXX implements 7-bit slave addressing.
The address byte is the first byte received following the
Start condition from the master device (see Figure 6-2).
The slave address is implemented in a nonvolatile register (Register 4-5) which is protected from accidental
register writes via the Slave Address Lock (SALCK)
configuration bit. The SALCK configuration bit requires
a high voltage (VIHH) to be modified. The SALCK configuration bit must be disabled (see Section 7.6 “Disable Configuration Bit (High-Voltage)”) before a
write to the nonvolatile Slave Addresses register can
modify the value.
Note:
After modifying the nonvolatile Slave
Address value (Register 4-5), it is strongly
recommended
that
the
SALCK
configuration bit is enabled (see
Section 7.5 “Enable Configuration Bit
(High-Voltage)”).
Acknowledge bit
Start bit
Read/Write bit
R/W ACK
Slave Address
Address Byte
Slave Address (7-bits)
1
1
A6 A5
0
0
A4
A3
0
0
A2 A1
0
A0 Address
A0 (1)
Table 6-1 shows the four standard order-able I2C slave
addresses and their respective device order code.
TABLE 6-1:
7-bit I2C™
Address
‘1100000’ (2)
‘1100001’ (2)
‘1100010’ (2)
‘1100011’ (2)
Note 1:
2:
6.8.0.1
I2C ADDRESS/ORDER CODE
Device Order Code(1)
Comment
MCP47FEBXXA0-E/ST
MCP47FEBXXA0T-E/ST
Tape and Reel
MCP47FEBXXA1-E/ST
MCP47FEBXXA1T-E/ST
Tape and Reel
MCP47FEBXXA2-E/ST
MCP47FEBXXA2T-E/ST
Tape and Reel
MCP47FEBXXA3-E/ST
MCP47FEBXXA3T-E/ST
Tape and Reel
‘xx’ in the order code indicates the resolution and number of output channels for the
device.
The devices I2C Slave Address can be
reprogrammed by the end user.
Custom I2C Slave Address Options
Custom I2C Slave Address options can be requested.
Customers can request the custom I2C Slave Address
via the Non-Standard Customer Authorization Request
(NSCAR) process.
Note 1: Non-Recurring
Engineering
(NRE)
charges
and
minimum
ordering
requirements for custom orders. Please
contact Microchip sales for additional
information.
2: A custom device will be assigned custom
device marking.
Note 1: Address Bits (A6:A0) can be reprogrammed by the customer (nonvolatile
device), but must unlock the Slave
Address with a High-Voltage command.
FIGURE 6-2:
I2C Control Byte.
Note:
Slave Address Bits in the
The I2C 10-bit Addressing mode is not
supported.
2015 Microchip Technology Inc.
DS20005375A-page 55
MCP47FEBXX
6.9
Entering High-Speed (HS) Mode
The I2C specification requires that a High-Speed mode
device must be ‘activated’ to operate in High-Speed
(3.4 Mbit/s) mode. This is done by the master sending
a special address byte following the Start bit. This byte
is referred to as the High-Speed Master Mode Code
(HSMMC).
The device can now communicate at up to 3.4 Mbit/s
on SDA and SCL lines. The device will switch out of the
HS mode on the next Stop condition.
The master code is sent as follows:
1.
2.
3.
Start condition (S)
High-Speed Master Mode Code (0000 1XXX),
The XXX bits are unique to the High-Speed (HS)
mode master.
No Acknowledge (A)
The MCP47FEBXX device does not acknowledge the
HS Select byte. However, upon receiving this command, the device switches to HS mode.
See Figure 6-3 for illustration of HS mode command
sequence.
For more information on the HS mode, or other I2C
modes, please refer to the NXP I2C specification.
6.9.1
SLOPE CONTROL
The slope control on the SDA output is different
between the Fast/Standard Speed and the High-Speed
clock modes of the interface.
6.9.2
PULSE GOBBLER
The pulse gobbler on the SCL pin is automatically
adjusted to suppress spikes VIHH (~9.0V)
on the HVC pin puts the device into High-Voltage
mode. High Voltage commands allow the device’s
WiperLock Technology and write-protect features to be
enabled and disabled.
Note 1: There is a required delay after the HVC
pin is driven to the VIHH level to the 1st
edge of the SCL pin.
2: The command sequence can go from an
increment to any other valid command for
the specified address. Issuing an
increment or decrement to a nonvolatile
location will cause an error condition
(A will be generated).
ACK bit (1, 2)
Write bit
ACK bit (1, 2)
(1)
ACK bit
Stop bit (2)
2
(1)
I C™ Slave Address
Memory Address Command
Memory Address Command
Start bit
SA SA SA SA SA SA SA
AD AD AD AD AD
S 6 5 4 3 2 1 0 0 A 4 3 2 1 0 1 0
Control Byte
Enable Command
AD AD AD AD AD
X A 4 3 2 1 0 1 0
X A P
Enable Command (3)
Note 1: The Slave address is determined by the NV Gain and I2C 7-bit Slave Address Register. The
default factory address is ‘110 0000b’ (C0h for Control byte with write, C1h for Control byte
with read).
2: This command sequence does not need to terminate (using the Stop bit) and can change to
any other desired command sequence (Disable, Read or Write).
3: This command byte is not required and the Stop bit may occur immediately after the 2nd ACK
bit in this sequence.
FIGURE 7-11:
I2C Enable Command Sequence.
2015 Microchip Technology Inc.
DS20005375A-page 67
MCP47FEBXX
7.6
Disable Configuration Bit
(High-Voltage)
7.6.1
The High Voltage Command (HVC) signal is used to
indicate that the command, or sequence of commands,
are in the High-Voltage mode. Signals >VIHH (~9.0V)
on the HVC pin puts MCP47FEBXX devices into HighVoltage mode. High Voltage commands allow the
device’s WiperLock Technology and write protect
features to be enabled and disabled.
Figure 7-12 (Disable) shows the formats for a single
Modify
Write
Protect or Wiper-Lock
Technology command.
A Modify Write Protect or Wiper-Lock Technology command will only start an EEPROM write
cycle (twc) after a properly formatted command has
been received and the Stop condition occurs.
Note 1: There is a required delay after the HVC
pin is driven to the VIHH level to the 1st
edge of the SCL pin.
During an EEPROM write cycle, only serial commands
to volatile memory are accepted. All other serial commands are ignored until the EEPROM write cycle (twc)
completes. This allows the Host Controller to operate
on the volatile DAC, the volatile VREF, Power-down,
Gain and Status, and WiperLock Technology Status
registers. The EEWA bit in the Status register indicates
the status of an EEPROM Write Cycle.
2: The command sequence can go from an
increment to any other valid command for
the specified address. Issuing an
increment or decrement to a nonvolatile
location will cause an error condition
(A will be generated).
ACK bit (1, 2)
Start bit
Write bit
ACK bit (1)
2
(1)
I C™ Slave Address
Address
Command
AD AD AD AD AD
SA SA SA SA SA SA SA
S 6 5 4 3 2 1 0 0 A 4 3 2 1 0 0 1
Control Byte
THE HIGH-VOLTAGE COMMAND
(HVC) SIGNAL
Disable Command
Address
ACK bit (1, 2)
Stop bit (2)
Command
AD AD AD AD AD
X A 4 3 2 1 0 0 1
X A P
Disable Command(3)
Note 1: The Slave address is determined by the NV Gain and I2C 7-bits Slave Address Register. The
default factory address is ‘110 0000b’ (C0h for Control byte with write, C1h for Control byte
with read).
2: This command sequence does not need to terminate (using the Stop bit) and can change to
any other desired command sequence (Enable, Read or Write).
3: This command byte is not required and the Stop bit may occur immediately after the 2nd ACK
bit in this sequence.
FIGURE 7-12:
DS20005375A-page 68
I2C Disable Command Sequence.
2015 Microchip Technology Inc.
MCP47FEBXX
Write bit
I2C™ Slave Address (1)
S 1
1
0
0 0
0
Address
0 A
0
Control Byte
0 0 0 0
Address
1 1 0 1
Enable Command
0
1 0
X A 1
Enable Command
0
1 0
X A 1
Address
0
0
0
Enable Command
0
Address
1
0
1
1 0
X A
DAC 0
(CL:DL)
Enable Command
1
1 0
X A P
SALCK
Note 1: The two command bits may either specify the Enable Command or the Disable Command.
FIGURE 7-13:
Configuring All User Configuration Bits Command Sequence (MCP47FEBX1).
Write bit
I2C™ Slave Address (1)
S 1
1
0
0 0
0
0
Control Byte
Address
0 A
0 0 0 0
Address
0 0 0 0
Address
1 1 0 1
Enable Command
0
1 0
X A 1
Enable Command
1
1 0
X A 1
Enable Command
0
1 0
X A 1
Address
0
0
0
Enable Command
0
Address
0
0
0
0
1
X A
DAC 0
(CL:DL)
Enable Command
1
Address
1
1 0
1 0
X A
DAC 1
(CL:DL)
Enable Command
1
1 0
X A P
SALCK
Note 1: The two command bits may either specify the Enable command or the Disable command.
FIGURE 7-14:
Configuring All User Configuration Bits Command Sequence (MCP47FEBX2).
2015 Microchip Technology Inc.
DS20005375A-page 69
MCP47FEBXX
NOTES:
DS20005375A-page 70
2015 Microchip Technology Inc.
MCP47FEBXX
TYPICAL APPLICATIONS
The MCP47FEBXX family of devices are general purpose, single/dual-channel voltage output DACs for various applications where a precision operation with
low-power and nonvolatile EEPROM memory is needed.
Since the devices include a nonvolatile EEPROM
memory, the user can utilize these devices for
applications that require the output to return to the
previous set-up value on subsequent power-ups.
8.1.1
The user can test the presence of the device on the I2C
bus line using a simple I2C command. This test can be
achieved by checking an acknowledge response from
the device after sending a Read or Write command.
Figure 8-1 shows an example with a Read command.
The steps are:
1.
2.
Applications generally suited for the devices are:
•
•
•
•
Set Point or Offset Trimming
Sensor Calibration
Portable Instrumentation (Battery-Powered)
Motor Control
8.1
Connecting to I2C BUS using
Pull-Up Resistors
The SCL and SDA pins of the MCP47FEBXX devices
are open-drain configurations. These pins require a
pull-up resistor, as shown in Figure 8-2.
The pull-up resistor values (R1 and R2) for SCL and
SDA pins depend on the operating speed (standard,
fast and high-speed) and loading capacitance of the I2C
bus line. A higher value of the pull-up resistor consumes
less power, but increases the signal transition time
(higher RC time constant) on the bus line. Therefore, it
can limit the bus operating speed. The lower resistor
value, on the other hand, consumes higher power, but
allows higher operating speed. If the bus line has higher
capacitance due to long metal traces or multiple device
connections to the bus line, a smaller pull-up resistor is
needed to compensate the long RC time constant. The
pull-up resistor is typically chosen between 1 k and
10 kranges for Standard and Fast modes, and less
than 1 kfor High-Speed mode.
2015 Microchip Technology Inc.
DEVICE CONNECTION TEST
3.
Set the R/W bit “High” in the device’s address byte.
Check the ACK bit of the address byte.
If the device acknowledges (ACK = 0) the
command, then the device is connected.
Otherwise, it is not connected.
Send Stop bit.
Address Byte
SCL
1 2 3 4 5 6 7 8
SDA
A6 A5 A4 A3 A2 A1 A0 1
Start
Bit
9
ACK
8.0
Stop
Bit
Address bits
R/W
Device
Response
FIGURE 8-1:
I2C Bus Connection Test.
DS20005375A-page 71
MCP47FEBXX
8.2
Power Supply Considerations
The power source should be as clean as possible. The
power supply to the device is also used for the DAC
voltage reference internally if the internal VDD is
selected as the resistor ladder’s reference voltage
(VRxB:VRxA = ’00’).
Any noise induced on the VDD line can affect the DAC
performance. Typical applications will require a bypass
capacitor in order to filter out high-frequency noise on
the VDD line. The noise can be induced onto the power
supply’s traces or as a result of changes on the DAC output. The bypass capacitor helps to minimize the effect of
these noise sources on signal integrity. Figure 8-2
shows an example of using two bypass capacitors (a
10 µF tantalum capacitor and a 0.1 µF ceramic capacitor) in parallel on the VDD line. These capacitors should
be placed as close to the VDD pin as possible (within
4 mm). If the application circuit has separate digital and
analog power supplies, the VDD and VSS pins of the
device should reside on the analog plane.
VDD
R1
VDD
C1
REF
2
8 SDA
7 SCL
VOUT0
3
6 LAT/HVC
4
5 V
SS
C2 V
Analog
Output
VOUT1
C3
1
R2
To MCU
MCP47FEBX2
C4
Optional
(a) Circuit when VDD is selected as reference
(Note: VDD is connected to the reference circuit internally.)
VDD
C1
C2
R1
VDD
VREF
C5
1
VREF 2
VOUT0
3
VOUT1
4
C6
Optional
Analog
Output
8 SDA
7 SCL
To MCU
6 LAT/HVC
5
MCP47FEBX2
C3
R2
VSS
C4
Optional
(b) Circuit when external reference is used.
R1 and R2 are I2C™ pull-up resistors:
R1 and R2:
5 k - 10 k for fSCL = 100 kHz to 400 kHz
~700 for fSCL = 3.4 MHz
C1 :
0.1 µF capacitor
C2 :
10 µF capacitor
Tantalum
C3 :
~ 0.1 µF
Optional to reduce noise
in VOUT pin.
C4 :
0.1 µF capacitor
Ceramic
C5 :
10 µF capacitor
Tantalum
C6 :
0.1 µF capacitor
Ceramic
FIGURE 8-2:
DS20005375A-page 72
Ceramic
Example Circuit.
2015 Microchip Technology Inc.
MCP47FEBXX
8.3
Application Examples
The MCP47FEBXX devices are rail-to-rail output DACs
designed to operate with a VDD range of 2.7V to 5.5V.
The internal output op amplifier is robust enough to
drive common, small-signal loads directly, thus
eliminating the cost and size of external buffers for
most applications. The user can use gain of 1 or 2 of
the output op amplifier by setting the Configuration
register bits. Also, the user can use internal VDD as the
reference or use external reference. Various user
options and easy-to-use features make the devices
suitable for various modern DAC applications.
Application examples include:
•
•
•
•
•
•
•
•
•
•
Decreasing Output Step Size
Building a “Window” DAC
Bipolar Operation
Selectable Gain and Offset Bipolar Voltage Output
Designing a Double-Precision DAC
Building Programmable Current Source
Serial Interface Communication Times
Software I2C Interface Reset Sequence
Power Supply Considerations
Layout Considerations
8.3.1
8.3.1.1
Decreasing Output Step Size
If the application is calibrating the bias voltage of a
diode or transistor, a bias voltage range of 0.8V may be
desired with about 200 µV resolution per step. Two
common methods to achieve small step size are using
lower VREF pin voltage or using a voltage divider on the
DAC’s output.
Using an external voltage reference (VREF) is an option
if the external reference is available with the desired
output voltage range. However, occasionally, when
using a low-voltage reference voltage, the noise floor
causes a SNR error that is intolerable. Using a voltage
divider method is another option, and provides some
advantages when external voltage reference needs to
be very low, or when the desired output voltage is not
available. In this case, a larger value reference voltage
is used, while two resistors scale the output range
down to the precise desired level.
Figure 8-3 illustrates this concept. A bypass capacitor
on the output of the voltage divider plays a critical
function in attenuating the output noise of the DAC and
the induced noise from the environment.
VDD
DC SET POINT OR CALIBRATION
A common application for the devices is a
digitally-controlled set point and/or calibration of
variable parameters, such as sensor offset or slope.
For example, the MCP47FEB2X provides 4096 output
steps. If voltage reference is 4.096V (where Gx = ‘0’),
the LSb size is 1 mV. If a smaller output step size is
desired, a lower external voltage reference is needed.
Optional
VREF VDD
RSENSE
MCP47FEBXX
VCC+
R1
VTRIP Comp.
VO
C1
R2
I2C™
VOUT
VCC–
2-wire
FIGURE 8-3:
Example Circuit Of Set Point
or Threshold Calibration.
EQUATION 8-1:
VOUT AND VTRIP
CALCULATIONS
VOUT = VREF • G •
DAC Register Value
2N
R2
V trip = V OUT --------------------
R 1 + R 2
2015 Microchip Technology Inc.
DS20005375A-page 73
MCP47FEBXX
8.3.1.2
8.4
Building a “Window” DAC
When calibrating a set point or threshold of a sensor,
typically only a small portion of the DAC output range is
utilized. If the LSb size is adequate enough to meet the
application’s accuracy needs, the unused range is
sacrificed without consequences. If greater accuracy is
needed, then the output range will need to be reduced
to increase the resolution around the desired threshold.
If the threshold is not near VREF, 2 • VREF, or VSS, then
creating a “window” around the threshold has several
advantages. One simple method to create this “window”
is to use a voltage divider network with a pull-up and
pull-down resistor. Figure 8-4 and Figure 8-6 illustrate
this concept.
Bipolar Operation
Bipolar operation is achievable by utilizing an external
operational amplifier. This configuration is desirable
due to the wide variety and availability of op amps. This
allows a general purpose DAC, with its cost and
availability advantages, to meet almost any desired
output voltage range, power and noise performance.
Figure 8-5 illustrates a simple bipolar voltage source
configuration. R1 and R2 allow the gain to be selected,
while R3 and R4 shift the DAC's output to a selected
offset. Note that R4 can be tied to VDD instead of VSS if
a higher offset is desired.
Optional
VREF VDD
Optional
VREF VDD
VCC+
RSENSE
MCP47FEBXX
R1
R3
VTRIP Comp.
VOUT
I2C™
2-wire
MCP47FEBXX
VCC+
C1
R2
VO
VCC+
R3
VOUT
I2C™
VOA+
VO
C1
R4
VCC–
2-wire
VCC–
R2
VIN
R1
VCC–
FIGURE 8-4:
DAC.
Single-Supply “Window”
FIGURE 8-5:
Digitally-Controlled Bipolar
Voltage Source Example Circuit.
EQUATION 8-2:
VOUT AND VTRIP
CALCULATIONS
EQUATION 8-3:
VOUT = VREF • G •
DAC Register Value
VOUT = VREF • G •
2N
V OUT R23 + V 23 R1
V TRIP = --------------------------------------------R 1 + R23
Thevenin
Equivalent
VOA+ =
R2R3
R23 = ------------------R2 + R3
DAC Register Value
2N
VOUT • R4
R3 + R4
VO = VOA+ • (1 +
VCC+ R2 + V CC- R 3
V23 = -----------------------------------------------------R 2 + R3
VOUT
VOUT, VOA+, AND VO
CALCULATIONS
R2
R1
) - VDD • (
R2
R1
)
R1
VTRIP
R23
V23
DS20005375A-page 74
2015 Microchip Technology Inc.
MCP47FEBXX
8.5
Selectable Gain and Offset Bipolar
Voltage Output
In some applications, precision digital control of the
output range is desirable. Figure 8-6 illustrates how to
use the DAC devices to achieve this in a bipolar or
single-supply application.
This circuit is typically used for linearizing a sensor
whose slope and offset varies.
The equation to design a bipolar “window” DAC would
be utilized if R3, R4 and R5 are populated.
8.5.1
BIPOLAR DAC EXAMPLE
Optional
VCC+
Optional
VREF VDD
R5
MCP47FEBXX
VO
I2C™
2-wire
Since
= 4096, 12-bit resolution is desired.
The equation can be simplified to:
R2
FIGURE 8-6:
Bipolar Voltage Source with
Selectable Gain and Offset.
EQUATION 8-6:
VOUT, VOA+, AND VO
CALCULATIONS
VOUT = VREF • G •
VOA+ =
DAC Register Value
R3 + R4
EQUATION 8-5:
R4
2
2.05V + 0.5 4.096V
------------------------ = ------------------------------------------------------- = -- R3 + R 4
1.5 4.096V
3
If R4 = 20 k, then R3 = 10 k
R2
R1
) - VIN • (
Offset Adjust
EQUATION 8-7:
If R1 = 20 k and R2 = 10 k, the gain will be 0.5.
Step 4: Next, solve for R3 and R4 by setting the
DAC to 4096, knowing that the output
needs to be +2.05V.
2N
VOUT • R4 + VCC- • R5
VO = VOA+ • ( 1 +
R2
1
------ = --R1
2
VCC–
C1 = 0.1 µF
EQUATION 8-4:
– R2
– 2.05
--------- = ----------------R1
4.096V
C1
R4
R1
Step 2: Calculate the resolution needed:
Step 3: The amplifier gain (R2/R1), multiplied by
full-scale VOUT (4.096V), must be equal to
the desired minimum output to achieve bipolar operation. Since any gain can be realized
by choosing resistor values (R1 + R2), the
VREF value must be selected first. If a VREF
of 4.096V is used, solve for the amplifier’s
gain by setting the DAC to 0, knowing that
the output needs to be -2.05V.
VOUT
VIN
Step 1: Calculate the range: +2.05V – (-2.05V) = 4.1V.
212
VOA+
VCC–
An output step size of 1 mV, with an output range of
±2.05V, is desired for a particular application.
4.1V/1 mV = 4100
VCC+
R3
Thevenin
Equivalent
R2
R1
)
Gain Adjust
BIPOLAR “WINDOW” DAC
USING R4 AND R5
V CC+ R 4 + VCC- R5
V 45 = --------------------------------------------R 4 + R5
VOUT R 45 + V 45 R 3
VIN+ = --------------------------------------------R3 + R 45
R4R5
R45 = ------------------R4 + R5
R2
R2
V O = V IN+ 1 + ------ – V A ------
R1
R1
Offset Adjust Gain Adjust
2015 Microchip Technology Inc.
DS20005375A-page 75
MCP47FEBXX
8.6
Designing a Double-Precision
DAC
8.7
Building Programmable Current
Source
Figure 8-7 shows an example design of a single-supply
voltage output capable of up to 24-bit resolution. This
requires two 12-bit DACs. This design is simply a
voltage divider with a buffered output.
Figure 8-8 shows an example of building a
programmable current source using a voltage follower.
The current sensor resistor is used to convert the DAC
voltage output into a digitally-selectable current source.
As an example, if a similar application to the one
developed in Section 8.5.1 “Bipolar DAC Example”
required a resolution of 1 µV instead of 1 mV, and a
range of 0V to 4.1V, then 12-bit resolution would not be
adequate.
The smaller RSENSE is, the less power dissipated
across it. However, this also reduces the resolution that
the current can be controlled.
Step 1: Calculate the resolution needed:
VDD
(or VREF)
Optional
4.1V/1 µV = 4.1 x 106.
Since 222 = 4.2 x 106, 22-bit resolution is
desired. Since DNL = ±1.0 LSb, this design
can be attempted with the 12-bit DAC.
Step 2: Since DAC1’s VOUT1 has a resolution of
1 mV, its output only needs to be “pulled”
1/1000 to meet the 1 µV target. Dividing
VOUT0 by 1000 would allow the application
to compensate for DAC1’s DNL error.
Step 3: If R2 is 100, then R1 needs to be 100 k.
Step 4: The resulting transfer function is shown in
the equation of Example 8-8.
VREF
VDD
VOUT
MCP47FEBXX
Load
VCC+
IL
Ib
VCC–
I2C™
2-wire
IL
Ib = ----
RSENSE
V OUT
I L = --------------- ------------R sense + 1
where Common-Emitter Current Gain
Optional
VDD
VREF
MCP47FEBX2
(DAC0)
I2C™
2-wire
FIGURE 8-8:
Source.
VOUT0
R1
Digitally-Controlled Current
VCC+
VOUT
Optional
VREF
VDD
0.1 µF
R2
MCP47FEBX2
(DAC1)
VCC–
VOUT1
I2C
2-wire
FIGURE 8-7:
Simple Double Precision
DAC using MCP47FEBX2.
EQUATION 8-8:
VOUT =
VOUT CALCULATION
VOUT0 * R2 + VOUT1 * R1
R1 + R2
Where:
VOUT0 = (VREF G DAC0 Register Value)/4096
VOUT1 = (VREF G DAC1 Register Value)/4096
Gx = Selected Op Amp Gain
DS20005375A-page 76
2015 Microchip Technology Inc.
MCP47FEBXX
8.8
Serial Interface Communication
Times
Table 8-1 shows time/frequency of the supported
operations of the I2C serial interface for the different
serial interface operational frequencies. This, along
with the VOUT output performance (such as slew rate),
would be used to determine your application’s volatile
DAC register update rate.
TABLE 8-1:
SERIAL INTERFACE TIMES / FREQUENCIES
Command
Code
Operation
HV
Mode(6)
C
1
C
0
Write Command
(Normal and HighVoltage)
0
0
(3)
Single
0
0
(3)
Continuous
Read Command
(Normal and HighVoltage) (2)
1
1
(3)
Random
1
1
(3)
Continuous
1
1
(3)
General Call Reset
Command
— —
General Call Wake-up
Command
— —
Enable Configuration
Bit (High-Voltage)
Command
1
0
Yes Single
1
0
Yes Continuous
Disable Configuration
Bit (High-Voltage)
Command
0
1
Yes Single
0
1
Yes Continuous
Note 1:
2:
3:
4:
5:
6:
# of Bit
Clocks
(1)
Data Update Rate
(8-bit/10-bit/12-bit)
(Data Words/Second)
Comments
100
kHz
400 kHz
3.4 MHz(5)
38
2,632
10,526
89,474
27n +
11
3,559
14,235
120,996
48
2,083
8,333
70,833
18n +
11
4,762
19,048
161,905
Last
Address
29
3,448
13,793
117,241
(3)
Single
20
5,000
20,000
170,000
Note 4
(3)
Single
20
5,000
20,000
170,000
Note 4
20
5,000
20,000
170,000
9n + 11
9,901
39,604
336,634
20
5,000
20,000
170,000
9n + 11
9,901
39,604
336,634
For 10 data words
For 10 data words
For 10 data words
For 10 data words
“n” indicates the number of times the command operation is to be repeated.
This command is useful to determine when an EEPROM programming cycle has completed.
This command can be either normal voltage or high voltage.
Determined by General Call command byte after the I2C General Call address.
There is a minimal overhead to enter into 3.4 MHz mode.
Nonvolatile Registers can only use the “Single” mode.
2015 Microchip Technology Inc.
DS20005375A-page 77
MCP47FEBXX
Software I2C Interface Reset
Sequence
This technique is documented in AN1028.
At times, it may become necessary to perform a
Software Reset Sequence to ensure the MCP47FEBXX
device is in a correct and known I2C interface state. This
technique only resets the I2C state machine.
This is useful if the MCP47FEBXX device powers-up in
an incorrect state (due to excessive bus noise, etc), or
if the master device is reset during communication.
Figure 8-9 shows the communication sequence to
software reset the device.
S
‘1’ ‘1’ ‘1’ ‘1’ ‘1’ ‘1’ ‘1’ ‘1’
S
P
Nine bits of ‘1’
Start bit
Stop bit
Start bit
FIGURE 8-9:
Format.
Software Reset Sequence
The 1st Start bit will cause the device to reset from a
state in which it is expecting to receive data from the
master device. In this mode, the device is monitoring
the data bus in Receive mode and can detect if the
Start bit forces an internal Reset.
8.10
Design Considerations
In the design of a system with the MCP47FEBXX
devices, the following considerations should be taken
into account:
• Power Supply Considerations
• Layout Considerations
8.10.1
The typical application will require a bypass capacitor
in order to filter high-frequency noise, which can be
induced onto the power supply's traces. The bypass
capacitor helps to minimize the effect of these noise
sources on signal integrity. Figure 8-10 illustrates an
appropriate bypass strategy.
In this example, the recommended bypass capacitor
value is 0.1 µF. This capacitor should be placed as close
(within 4 mm) to the device power pin (VDD) as possible.
The power source supplying these devices should be
as clean as possible. If the application circuit has
separate digital and analog power supplies, VDD and
VSS should reside on the analog plane.
The nine bits of ‘1’ are used to force a Reset of those
devices that could not be reset by the previous Start bit.
This occurs only if the MCP47FEBXX is driving an A bit
on the I2C bus, or is in Output mode (from a Read
command) and is driving a data bit of ‘0’ onto the I2C
bus. In both of these cases, the previous Start bit could
not be generated due to the MCP47FEBXX holding the
bus low. By sending out nine ‘1’ bits, it is ensured that
the device will see an A bit (the master device does not
drive the I2C bus low to acknowledge the data sent by
the MCP47FEBXX), which also forces the
MCP47FEBXX to reset.
The 2nd Start bit is sent to address the rare possibility
of an erroneous write. This could occur if the master
device was reset while sending a Write command to
the MCP47FEBXX, AND then as the master device
returns to normal operation and issues a Start condition, while the MCP47FEBXX is issuing an acknowledge. In this case, if the 2nd Start bit is not sent (and the
Stop bit was sent) the MCP47FEBXX could initiate a
write cycle.
Note:
The potential for this erroneous write
ONLY occurs if the master device is reset
while sending a Write command to the
MCP47FEBxx.
The Stop bit terminates the current I2C bus activity. The
MCP47FEBXX waits to detect the next Start condition.
DS20005375A-page 78
POWER SUPPLY
CONSIDERATIONS
VDD
0.1 µF
VDD
0.1 µF
VREF
VOUT
VSS
FIGURE 8-10:
Connections.
SCL
SDA
PIC® Microcontroller
Note:
This sequence does not affect any other I2C devices
which may be on the bus, as they should disregard this
as an invalid command.
MCP47FEBXX
8.9
VSS
Typical Microcontroller
2015 Microchip Technology Inc.
MCP47FEBXX
LAYOUT CONSIDERATIONS
Several layout considerations may be applicable to
your application. These may include:
• Noise
• PCB Area Requirements
8.10.2.1
8.10.2.2
PACKAGE FOOTPRINT(1)
TABLE 8-2:
Package
Noise
Inductively-coupled AC transients and digital switching
noise can degrade the input and output signal integrity,
potentially masking the MCP47FEBXX’s performance.
Careful board layout minimizes these effects and
increases the Signal-to-Noise Ratio (SNR). Multi-layer
boards utilizing a low-inductance ground plane,
isolated inputs, isolated outputs and proper decoupling
are critical to achieving the performance that the silicon
is capable of providing. Particularly harsh
environments may require shielding of critical signals.
PCB Area Requirements
In some applications, PCB area is a criteria for device
selection. Table 8-2 shows the typical package
dimensions and area for the different package options.
Pins
8.10.2
8
Type
Package Footprint
Code
Dimensions
(mm)
Area (mm2)
Length Width
TSSOP
Note 1:
ST
3.00
4.40
13.20
Does not include recommended land
pattern dimensions. Dimensions are
typical values.
Separate digital and analog ground planes are
recommended. In this case, the VSS pin and the ground
pins of the VDD capacitors should be terminated to the
analog ground plane.
Note:
Breadboards and wire-wrapped boards
are not recommended.
2015 Microchip Technology Inc.
DS20005375A-page 79
MCP47FEBXX
NOTES:
DS20005375A-page 80
2015 Microchip Technology Inc.
MCP47FEBXX
9.0
DEVELOPMENT SUPPORT
9.2
Several additional technical documents are available to
assist you in your design and development. These
technical documents include Application Notes,
Technical Briefs, and Design Guides. Table 9-2 shows
some of these documents.
Development support can be classified into two groups.
These are:
• Development Tools
• Technical Documentation
9.1
Technical Documentation
Development Tools
Several development tools are available to assist in your
design and evaluation of the MCP47FEBXX devices.
The currently available tools are shown in Table 9-1.
Figure 9-1 shows how the TSSOP20EV bond-out PCB
can be populated to easily evaluate the MCP47FEBXX
devices. The 8-pin and 20-pin TSSOP packages have
the same pin pitch (0.65 mm BSC) and package width
(4.40 mm typ.), and the 8-pin TSSOP package can be
placed on the 20-pin TSSOP footprint. Device evaluation can use the PICkit™ Serial Analyzer to control the
DAC output registers and state of the configuration,
control and status register.
The TSSOP20EV boards may be purchased directly
from the Microchip web site at www.microchip.com.
TABLE 9-1:
DEVELOPMENT TOOLS (Note 1)
Board Name
Part #
Comment
20-Pin TSSOP and SSOP Evaluation Board
TSSOP20EV
14-pin SOIC/TSSOP/DIP Evaluation Board
SOIC14EV
SOIC-8 Evaluation Board
SOIC8EV
Note 1:
Most Flexible option - Recommended Bond-out PCB
Supports the PICkit™ Serial Analyzer. See the User’s Guide for additional information and requirements.
TABLE 9-2:
TECHNICAL DOCUMENTATION
Application
Note Number
Title
Literature #
AN1326
Using the MCP4728 12-Bit DAC for LDMOS Amplifier Bias Control Applications
DS01326
—
Signal Chain Design Guide
DS21825
—
Analog Solutions for Automotive Applications Design Guide
DS01005
2015 Microchip Technology Inc.
DS20005375A-page 81
MCP47FEBXX
MCP47FEBXX-A0E/ST
installed in U3 (bottom 8 pins of TSSOP-20 footprint)
Connected to
Digital Ground
(DGND) Plane
Connected to
Digital Power (VL) Plane
47FEB
1.0 µF
VDD
0
4.7k
4.7k
VREF
NC/VOUT1
0
Two blue wire jumpers to connect
PICkit™ Serial interface (I2C™) to device pins
DS20005375A-page 82
SCL
LAT/HVC
VOUT0
FIGURE 9-1:
SDA
VSS
1x6 male header, with 90° right angle
MCP47FEBXX Evaluation Board Circuit Using TSSOP20EV.
2015 Microchip Technology Inc.
MCP47FEBXX
10.0
PACKAGING INFORMATION
10.1
Package Marking Information
8-Lead TSSOP (4.4 mm)
Example
AAAG
E449
256
XYWW
Device Number
Code
Device Number
Code
MCP47FEB01A0-E/ST
AAAG
MCP47FEB12A0-E/ST
AAAL
MCP47FEB01A0T-E/ST
AAAG
MCP47FEB12A0T-E/ST
AAAL
MCP47FEB01A1-E/ST
AAAU
MCP47FEB12A1-E/ST
AABG
MCP47FEB01A1T-E/ST
AAAU
MCP47FEB12A1T-E/ST
AABG
MCP47FEB01A2-E/ST
AAAV
MCP47FEB12A2-E/ST
AABH
MCP47FEB01A2T-E/ST
AAAV
MCP47FEB12A2T-E/ST
AABH
MCP47FEB01A3-E/ST
AAAW
MCP47FEB12A3-E/ST
AABJ
MCP47FEB01A3T-E/ST
AAAW
MCP47FEB12A3T-E/ST
AABJ
MCP47FEB02A0-E/ST
AAAK
MCP47FEB21A0-E/ST
AAAJ
MCP47FEB02A0T-E/ST
AAAK
MCP47FEB21A0T-E/ST
AAAJ
MCP47FEB02A1-E/ST
AABD
MCP47FEB21A1-E/ST
AABA
MCP47FEB02A1T-E/ST
AABD
MCP47FEB21A1T-E/ST
AABA
MCP47FEB02A2-E/ST
AABE
MCP47FEB21A2-E/ST
AABB
MCP47FEB02A2T-E/ST
AABE
MCP47FEB21A2T-E/ST
AABB
MCP47FEB02A3-E/ST
AABF
MCP47FEB21A3-E/ST
AABC
MCP47FEB02A3T-E/ST
AABF
MCP47FEB21A3T-E/ST
AABC
MCP47FEB11A0-E/ST
AAAH
MCP47FEB22A0-E/ST
AAAM
MCP47FEB11A0T-E/ST
AAAH
MCP47FEB22A0T-E/ST
AAAM
MCP47FEB11A1-E/ST
AAAX
MCP47FEB22A1-E/ST
AABK
MCP47FEB11A1T-E/ST
AAAX
MCP47FEB22A1T-E/ST
AABK
MCP47FEB11A2-E/ST
AAAY
MCP47FEB22A2-E/ST
AABL
MCP47FEB11A2T-E/ST
AAAY
MCP47FEB22A2T-E/ST
AABL
MCP47FEB11A3-E/ST
AAAZ
MCP47FEB22A3-E/ST
AABM
MCP47FEB11A3T-E/ST
AAAZ
MCP47FEB22A3T-E/ST
AABM
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC® designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
2015 Microchip Technology Inc.
DS20005375A-page 83
MCP47FEBXX
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