2.5 V to 5.5 V, Parallel Interface
Octal Voltage Output 8-/10-/12-Bit DACs
AD5346/AD5347/AD5348
Data Sheet
FEATURES
GENERAL DESCRIPTION
AD5346: octal 8-bit DAC
AD5347: octal 10-bit DAC
AD5348: octal 12-bit DAC
Low power operation: 1.4 mA (max) at 3.6 V
Power-down to 120 nA at 3 V, 400 nA at 5 V
Guaranteed monotonic by design over all codes
Rail-to-rail output range: 0 V to VREF or 0 V to 2 × VREF
Power-on reset to 0 V
Simultaneous update of DAC outputs via LDAC pin
Asynchronous CLR facility
Readback
Buffered/unbuffered reference inputs
20 ns WR time
38-lead TSSOP/6 mm × 6 mm 40-lead LFCSP packaging
Temperature range: –40°C to +105°C
The AD5346/AD5347/AD53481 are octal 8-, 10-, and 12-bit
DACs, operating from a 2.5 V to 5.5 V supply. These devices
incorporate an on-chip output buffer that can drive the output
to both supply rails, and also allow a choice of buffered or
unbuffered reference input.
APPLICATIONS
An asynchronous CLR input is also provided, which resets the
contents of the input register and the DAC register to all zeros.
These devices also incorporate a power-on reset circuit that
ensures that the DAC output powers on to 0 V and remains
there until valid data is written to the device.
The AD5346/AD5347/AD5348 have a parallel interface. CS
selects the device and data is loaded into the input registers on
the rising edge of WR. A readback feature allows the internal
DAC registers to be read back through the digital port.
The GAIN pin on these devices allows the output range to be
set at 0 V to VREF or 0 V to 2 × VREF.
Input data to the DACs is double-buffered, allowing simultaneous update of multiple DACs in a system using the LDAC pin.
Portable battery-powered instruments
Digital gain and offset adjustment
Programmable voltage and current sources
Optical networking
Automatic test equipment
Mobile communications
Programmable attenuators
Industrial process control
All three parts are pin compatible, which allows users to select
the amount of resolution appropriate for their application
without redesigning their circuit board.
FUNCTIONAL BLOCK DIAGRAM
VDD
AGND
VREFAB
DGND
VREFCD
POWER-ON
RESET
AD5348
BUF
INPUT
REGISTER
DAC
REGISTER
STRING
DAC A
BUFFER
INPUT
REGISTER
DAC
REGISTER
STRING
DAC B
BUFFER
VOUTB
INPUT
REGISTER
DAC
REGISTER
STRING
DAC C
BUFFER
VOUTC
INPUT
REGISTER
DAC
REGISTER
STRING
DAC D
BUFFER
VOUTD
WR
INPUT
REGISTER
DAC
REGISTER
STRING
DAC E
BUFFER
VOUTE
A2
INPUT
REGISTER
DAC
REGISTER
STRING
DAC F
BUFFER
VOUTF
A1
INPUT
REGISTER
DAC
REGISTER
STRING
DAC G
BUFFER
VOUTG
INPUT
REGISTER
DAC
REGISTER
STRING
DAC H
BUFFER
VOUTH
GAIN
DB11
..
.
DB0
CS
RD
A0
INTERFACE
LOGIC
VOUTA
POWER-DOWN
LOGIC
LDAC
VREFGH
VREFEF
03331-0-001
CLR
PD
Figure 1.
1
Protected by U.S. Patent No. 5,969,657.
Rev. A
Document Feedback
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Tel: 781.329.4700 ©2003–2015 Analog Devices, Inc. All rights reserved.
Technical Support
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AD5346/AD5347/AD5348
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Parallel Interface ......................................................................... 17
Applications ....................................................................................... 1
Power-On Reset .......................................................................... 18
General Description ......................................................................... 1
Power-Down Mode .................................................................... 18
Functional Block Diagram .......................................................... 1
Suggested Data Bus Formats ..................................................... 19
Revision History ............................................................................... 2
Applications Information .............................................................. 20
Specifications..................................................................................... 3
Typical Application Circuits ..................................................... 20
AC Characteristics........................................................................ 5
Bipolar Operation Using the AD5346/AD5347/AD5348 ..... 20
Timing Characteristics ................................................................ 5
Decoding Multiple AD5346/AD5347/AD5348s .................... 21
Absolute Maximum Ratings............................................................ 7
ESD Caution .................................................................................. 7
AD5346/AD5347/AD5348 as Digitally Programmable
Window Detectors ...................................................................... 21
Pin Configurations and Function Descriptions ........................... 8
Programmable Current Source ................................................ 21
Terminology .................................................................................... 11
Coarse and Fine Adjustment Using the
AD5346/AD5347/AD5348 ....................................................... 22
Typical Performance Characteristics ........................................... 13
Functional Description .................................................................. 17
Digital-to-Analog Section ......................................................... 17
Resistor String ............................................................................. 17
Power Supply Bypassing and Grounding ................................ 22
Outline Dimensions ....................................................................... 23
Ordering Guide .......................................................................... 24
DAC Reference Input ................................................................. 17
Output Amplifier ........................................................................ 17
REVISION HISTORY
6/15—Rev. 0 to Rev. A
Changes to Figure 6 .......................................................................... 8
Changes to Figure 8 .......................................................................... 9
Changes to Figure 10 ...................................................................... 10
Deleted Driving VDD from the Reference Voltage Section and
Figure 42; Renumbered Sequentially ........................................... 20
Deleted Table 9 and Table 10; Renumbered Sequentially ......... 23
Updated Outline Dimensions ....................................................... 23
Changes to Ordering Guide .......................................................... 24
11/03—Revision 0: Initial Version
Rev. A | Page 2 of 24
Data Sheet
AD5346/AD5347/AD5348
SPECIFICATIONS
VDD = 2.5 V to 5.5 V; VREF = 2 V; RL = 2 kΩ to GND; CL = 200 pF to GND; all specifications TMIN to TMAX, unless otherwise noted.
Table 1.
2
Parameter
DC PERFORMANCE3, 4
AD5346
Resolution
Relative Accuracy
Differential Nonlinearity
AD5347
Resolution
Relative Accuracy
Differential Nonlinearity
AD5348
Resolution
Relative Accuracy
Differential Nonlinearity
Offset Error
Gain Error
Lower Deadband5
Min
B Version1
Typ
Max
Unit
Test Conditions/Comments
8
±0.15
±0.02
±1
±0.25
Bits
LSB
LSB
Guaranteed monotonic by design over all codes
10
±0.5
±0.05
±4
±0.5
Bits
LSB
LSB
Guaranteed monotonic by design over all codes
±16
±1
±3
±1
60
Bits
LSB
LSB
% of FSR
% of FSR
mV
12
±2
±0.2
±0.4
±0.1
10
Upper Deadband5
Offset Error Drift6
10
–12
Gain Error Drift6
–5
DC Power Supply Rejection Ratio6
DC Crosstalk6
–60
200
DAC REFERENCE INPUT6
VREF Input Range
VREF Input Range
VREF Input Impedance
Reference Feedthrough
Channel-to-Channel Isolation
OUTPUT CHARACTERISTICS6
Minimum Output Voltage4, 7
Maximum Output Voltage4, 7
DC Output Impedance
Short Circuit Current
Power-Up Time
1
0.25
60
VDD
VDD
>10
90
45
–90
–75
0.001
VDD –
0.001
0.5
25
16
2.5
5
mV
ppm of
FSR/°C
ppm of
FSR/°C
dB
μV
Guaranteed monotonic by design over all codes
Lower deadband exists only if offset error is
negative
VDD = 5 V; upper deadband exists only if VREF = VDD
∆VDD = ±10%
RL = 2 kΩ to GND, 2 kΩ to VDD; CL = 200 pF to GND;
Gain = +1
V
V
MΩ
kΩ
kΩ
dB
dB
Buffered reference mode
Unbuffered reference mode
Buffered reference mode and power-down mode
Gain = +1; input impedance = RDAC
Gain = +2; input impedance = RDAC
Frequency = 10 kHz
Frequency = 10 kHz
V min
V max
Rail-to-rail operation
Ω
mA
mA
μs
μs
Rev. A | Page 3 of 24
VDD = 5 V
VDD = 3 V
Coming out of power-down mode; VDD = 5 V
Coming out of power-down mode; VDD = 3 V
AD5346/AD5347/AD5348
Parameter
LOGIC INPUTS6
Input Current
VIL, Input Low Voltage
Min
VIH, Input High Voltage
Pin Capacitance
LOGIC OUTPUTS6
VDD = 4.5 V to 5.5 V
Output Low Voltage, VOL
Output High Voltage, VOH
VDD = 2.5 V to 3.6 V
Output Low Voltage, VOL
Output High Voltage, VOH
1.7
2
POWER REQUIREMENTS
VDD
IDD (Normal Mode)
VDD = 4.5 V to 5.5 V
VDD = 2.5 V to 3.6 V
IDD (Power-Down Mode)
VDD = 4.5 V to 5.5 V
VDD = 2.5 V to 3.6 V
Data Sheet
B Version 1
Typ
Max
Unit
Test Conditions/Comments
±1
0.8
0.7
0.6
µA
V
V
V
V
pF
VDD = 5 V ±10%
VDD = 3 V ±10%
VDD = 2.5 V
VDD = 2.5 V to 5.5 V
0.4
V
V
ISINK = 200 µA
ISOURCE = 200 µA
0.4
V
V
ISINK = 200 µA
ISOURCE = 200 µA
5.5
V
1
0.8
1.65
1.4
mA
mA
0.4
0.12
1
1
µA
µA
5
VDD – 1
VDD –
0.5
2.5
VIH = VDD, VIL = GND
All DACs in unbuffered mode. In buffered mode,
extra current is typically x µA per DAC,
where x = 5 µA + VREF/RDAC
VIH = VDD, VIL = GND
Temperature range: B Version: −40°C to +105°C; typical specifications are at 25°C.
See the Terminology section.
Linearity is tested using a reduced code range: AD5346 (Code 8 to Code 255); AD5347 (Code 28 to Code 1023); AD5348 (Code 115 to Code 4095).
4
DC specifications tested with outputs unloaded.
5
This corresponds to x codes. x = deadband voltage/LSB size.
6
Guaranteed by design and characterization, not production tested.
7
For the amplifier output to reach its minimum voltage, offset error must be negative. For the amplifier output to reach its maximum voltage, VREF = VDD and the offset
plus gain error must be positive.
1
2
3
Rev. A | Page 4 of 24
Data Sheet
AD5346/AD5347/AD5348
AC CHARACTERISTICS
VDD = 2.5 V to 5.5 V; RL = 2 kΩ to GND; CL = 200 pF to GND; all specifications TMIN to TMAX, unless otherwise noted. Guaranteed
by design and characterization, not production tested.
Table 2.
2
Parameter
Output Voltage Settling Time
AD5346
AD5347
AD5348
Slew Rate
Major Code Transition Glitch Energy
Digital Feedthrough
Digital Crosstalk
Analog Crosstalk
DAC-to-DAC Crosstalk
Multiplying Bandwidth
Total Harmonic Distortion
2
Unit
6
7
8
0.7
8
0.5
1
1
3.5
200
–70
μs
μs
μs
V/μs
nV-s
nV-s
nV-s
nV-s
nV-s
kHz
dB
8
9
10
Test Conditions/Comments
VREF = 2 V
1/4 scale to 3/4 scale change (40 H to C0 H)
1/4 scale to 3/4 scale change (100 H to 300 H)
1/4 scale to 3/4 scale change (400 H to C00 H)
1 LSB change around major carry
VREF = 2 V ±0.1 V p-p; unbuffered mode
VREF = 2. V ±0.1 V p-p; frequency = 10 kHz; unbuffered mode
Temperature range: B Version: −40°C to +105°C; typical specifications are at 25°C.
See the Terminology section.
200A
TO OUTPUT
PIN
IOL
VOH(min) + VOL(max)
2
CL
50pF
200A
03331-0-002
1
B Version1
Min
Typ
Max
IOH
Figure 2. Load Circuit for Digital Output Timing Specifications
TIMING CHARACTERISTICS
VDD = 2.5 V to 5.5 V; all specifications TMIN to TMAX, unless otherwise noted. Guaranteed by design and characterization, not
production tested. All input signals are specified with tr = tf = 5 ns (10% to 90% of VDD) and timed from a voltage level of (VIL + VIH)/2.
See Figure 2.
Table 3.
Parameter
Data Write Mode (Figure 3)
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
t11
t12
t13
t14
t15
Limit at TMIN, TMAX
Unit
Test Condition/Comments
0
0
20
5
4.5
5
5
4.5
5
4.5
20
10
20
20
0
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
CS to WR setup time
CS to WR hold time
WR pulse width
Data, GAIN, BUF setup time
Data, GAIN, BUF hold time
Synchronous mode. WR falling to LDAC falling.
Synchronous mode. LDAC falling to WR rising.
Synchronous mode. WR rising to LDAC rising.
Asynchronous mode. LDAC rising to WR rising.
Asynchronous mode. WR rising to LDAC falling.
LDAC pulse width
CLR pulse width
Time between WR cycles
A0, A1, A2 setup time
A0, A1, A2 hold time
Rev. A | Page 5 of 24
AD5346/AD5347/AD5348
Parameter
Data Readback Mode (Figure 4)
t16
t17
t18
t19
t20
t21
t22
t23
t24
t25
t26
t1
Data Sheet
Limit at TMIN, TMAX
Unit
Test Condition/Comments
0
0
0
20
30
0
22
30
4
30
22
30
30
30
30
50
ns min
ns min
ns min
ns min
ns min
ns min
ns max
ns max
ns min
ns max
ns max
ns max
ns min
ns min
ns min
ns min
A0, A1, A2 to CS setup time
A0, A1, A2 to CS hold time
CS to falling edge of RD
RD pulse width; VDD = 3.6 V to 5.5 V
RD pulse width; VDD = 2.5 V to 3.6 V
CS to RD hold time
Data access time after falling edge of RD; VDD = 3.6 V to 5.5 V
Data access time after falling edge of RD VDD = 2.5 V to 3.6 V
Bus relinquish time after rising edge of RD
CS falling edge to data; VDD = 3.6 V to 5.5 V
CS falling edge to data; VDD = 2.5 V to 3.6 V
Time between RD cycles
Time from RD to WR
Time from WR to RD, VDD = 3.6 V to 5.5 V
Time from WR to RD, VDD = 2.5 V to 3.6 V
t2
A0–A2
CS
t3
t13
t4
DATA,
GAIN, BUF
LDAC1
t6
t7
t9
CS
t5
t18
t20
t19
t8
t24
RD
t10
t21
t11
LDAC2
CLR
t17
t16
WR
t22
DATA
t23
t12
t14
t15
t25
WR
t26
03331-0-003
NOTES
1. SYNCHRONOUS LDAC UPDATE MODE
2. ASYNCHRONOUS LDAC UPDATE MODE
Figure 4. Parallel Interface Read Timing Diagram
Figure 3. Parallel Interface Write Timing Diagram
Rev. A | Page 6 of 24
03331-0-004
A0–A2
Data Sheet
AD5346/AD5347/AD5348
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 4.
Parameter
VDD to GND
Digital Input Voltage to GND
Digital Output Voltage to GND
Reference Input Voltage to GND
VOUT to GND
Operating Temperature Range
Industrial (B Version)
Storage Temperature Range
Junction Temperature
38-Lead TSSOP Package
Power Dissipation
θJA Thermal Impedance
θJC Thermal Impedance
40-Lead LFCSP Package
Power Dissipation
θJA Thermal Impedance (3-layer
board)
Lead Temperature, Soldering (10 sec)
IR Reflow, Peak Temperature
Rating
–0.3 V to +7 V
–0.3 V to VDD + 0.3 V
–0.3 V to VDD + 0.3 V
–0.3 V to VDD + 0.3 V
–0.3 V to VDD + 0.3 V
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those listed in the operational
sections of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
ESD CAUTION
–40°C to +105°C
–65°C to +150°C
150°C
(TJ max − TA)/ θJA mW
98.3°C/W
8.9°C/W
(TJ max − TA)/ θJA mW
29.6°C/W
300°C
220°C
Rev. A | Page 7 of 24
AD5346/AD5347/AD5348
Data Sheet
38
PD
37
CLR
VREFCD 3
36
GAIN
VDD 4
35
WR
VREFAB 5
34
RD
VOUTA 6
8-BIT
33
CS
VOUTB 7
AD5346
32
DB7
VOUTA 1
VOUTB 2
VOUTC 3
VOUTD 4
AGND 5
AGND 6
VOUTE 7
VOUTF 8
VOUTG 9
VOUTH 10
TOP VIEW 31
DB6
(Not to Scale)
30 DB5
VOUTD 9
DB4
28
DB3
VOUTF 12
27
DB2
VOUTG 13
26
DB1
VOUTH 14
25
DB0
DGND 15
24
DGND
BUF 16
23
DGND
LDAC 17
22
DGND
A0 18
21
DGND
A1 19
20
A2
DGND
BUF
LDAC
A0
A1
A2
DGND
DGND
DGND
DGND
29
NOTES
1. EXPOSED PAD. THE EXPOSED PAD MUST BE TIED TO GND.
03331-0-005
AGND 10
VOUTE 11
TOP VIEW
(Not to Scale)
RD
CS
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
11
12
13
14
15
16
17
18
19
20
VOUTC 8
8-BIT
AD5346
30
29
28
27
26
25
24
23
22
21
03331-006
1
VREFEF 2
40
39
38
37
36
35
34
33
32
31
VREFGH
VREF AB
VDD
VDD
VREF CD
VREF EF
VREF GH
PD
CLR
GAIN
WR
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
Figure 6. AD5346 Pin Configuration—LFCSP
Figure 5. AD5346 Pin Configuration—TSSOP
Table 5. AD5346 Pin Function Descriptions
Pin No.
TSSOP
LFCSP
1
35
2
36
3
37
4
38, 39
Mnemonic
VREFGH
VREFEF
VREFCD
VDD
5
6 to 9,
11 to 14
10
15,
21 to 24
16
17
40
1 to 4,
7 to 10
5, 6
11,
17 to 20
12
13
VREFAB
VOUTX
Description
Reference Input for DACs G and H.
Reference Input for DACs E and F.
Reference Input for DACs C and D.
Power Supply Pin(s). This part can operate from 2.5 V to 5.5 V, and the supply should be decoupled
with a 10 µF capacitor in parallel with a 0.1 µF capacitor to GND. Both VDD pins on the LFCSP
package must be at the same potential.
Reference Input for DACs A and B.
Output of DAC X. Buffered output with rail-to-rail operation.
AGND
DGND
Analog Ground. Ground reference for analog circuitry.
Digital Ground. Ground reference for digital circuitry.
BUF
LDAC
18
19
20
25 to 32
33
14
15
16
21 to 28
29
A0
A1
A2
DB0 to DB7
CS
34
35
36
37
38
Not
applicable
30
31
32
33
34
41
RD
WR
GAIN
CLR
PD
EPAD
Buffer Control Pin. Controls whether the reference input to the DAC is buffered or unbuffered.
Active Low Control Input. Updates the DAC registers with the contents of the input registers, which
allows all DAC outputs to be simultaneously updated.
LSB Address Pin. Selects which DAC is to be written to.
Address Pin. Selects which DAC is to be written to.
MSB Address Pin. Selects which DAC is to be written to.
Eight Parallel Data Inputs. DB7 is the MSB of these eight bits.
Active Low Chip Select Input. Used in conjunction with WR to write data to the parallel interface, or
with RD to read back data from a DAC.
Active Low Read Input. Used in conjunction with CS to read data back from the internal DACs.
Active Low Write Input. Used in conjunction with CS to write data to the parallel interface.
Gain Control Pin. Controls whether the output range from the DAC is 0 V to VREF or 0 V to 2 × VREF.
Asynchronous Active Low Control Input. Clears all input registers and DAC registers to zeros.
Power-Down Pin. This active low control pin puts all DACs into power-down mode.
Exposed Pad. The exposed pad must be tied to GND.
Rev. A | Page 8 of 24
AD5346/AD5347/AD5348
38
PD
37
CLR
VREFCD 3
36
GAIN
VDD 4
35
WR
VREFAB 5
34
RD
VOUTA 6
10-BIT
33
CS
VOUTB 7
AD5347
32
DB9
VOUTA 1
VOUTB 2
VOUTC 3
VOUTD 4
AGND 5
AGND 6
VOUTE 7
VOUTF 8
VOUTG 9
VOUTH 10
TOP VIEW 31
DB8
(Not to Scale)
30 DB7
VOUTD 9
DB6
DB5
VOUTF 12
27
DB4
VOUTG 13
26
DB3
VOUTH 14
25
DB2
DGND 15
24
DB1
BUF 16
23
DB0
LDAC 17
22
DGND
A0 18
21
DGND
A1 19
20
A2
DGND
BUF
LDAC
A0
A1
A2
DGND
DGND
DB0
DB1
29
28
NOTES
1. EXPOSED PAD. THE EXPOSED PAD MUST BE TIED TO GND.
03331-0-007
AGND 10
VOUTE 11
TOP VIEW
(Not to Scale)
RD
CS
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
11
12
13
14
15
16
17
18
19
20
VOUTC 8
10-BIT
AD5347
30
29
28
27
26
25
24
23
22
21
03331-008
1
VREFEF 2
40
39
38
37
36
35
34
33
32
31
VREFGH
VREF AB
VDD
VDD
VREF CD
VREF EF
VREF GH
PD
CLR
GAIN
WR
Data Sheet
Figure 8. AD5347 Pin Configuration—LFCSP
Figure 7. AD5347 Pin Configuration—TSSOP
Table 6. AD5347 Pin Function Descriptions
TSSOP
1
2
3
4
Pin No.
LFCSP
35
36
37
38, 39
VREFAB
VOUTX
AGND
DGND
Analog Ground. Ground reference for analog circuitry.
Digital Ground. Ground reference for digital circuitry.
16
17
40
1 to 4,
7 to 10
5, 6
11,
17 to 18
12
13
Description
Reference Input for DACs G and H.
Reference Input for DACs E and F.
Reference Input for DACs C and D.
Power Supply Pin(s). This part can operate from 2.5 V to 5.5 V, and the supply should be decoupled
with a 10 µF capacitor in parallel with a 0.1 µF capacitor to GND. Both VDD pins on the LFCSP
package must be at the same potential.
Reference Input for DACs A and B.
Output of DAC X. Buffered output with rail-to-rail operation.
BUF
LDAC
18
19
20
23 to 32
33
14
15
16
19 to 28
29
A0
A1
A2
DB0 to DB9
CS
34
35
36
37
38
Not
applicable
30
31
32
33
34
41
RD
WR
GAIN
CLR
PD
EPAD
Buffer Control Pin. Controls whether the reference input to the DAC is buffered or unbuffered.
Active Low Control Input. Updates the DAC registers with the contents of the input registers,
which allows all DAC outputs to be simultaneously updated.
LSB Address Pin. Selects which DAC is to be written to.
Address Pin. Selects which DAC is to be written to.
MSB Address Pin. Selects which DAC is to be written to.
Ten Parallel Data Inputs. DB9 Is the MSB of these ten bits.
Active Low Chip Select Input. Used in conjunction with WR to write data to the parallel interface,
or with RD to read back data from a DAC.
Active Low Read Input. Used in conjunction with CS to read data back from the internal DACs.
Active Low Write Input. Used in conjunction with CS to write data to the parallel interface.
Gain Control Pin. Controls whether the output range from the DAC is 0 V to VREF or 0 V to 2 × VREF.
Asynchronous Active Low Control Input. Clears all input registers and DAC registers to zeros.
Power-Down Pin. This active low control pin puts all DACs into power-down mode.
Exposed Pad. The exposed pad must be tied to GND.
5
6 to 9,
11 to 14
10
15, 21 to 22
Mnemonic
VREFGH
VREFEF
VREFCD
VDD
Rev. A | Page 9 of 24
38
PD
37
CLR
VREFCD 3
36
GAIN
VDD 4
35
WR
VREFAB 5
34
RD
VOUTA 6
12-BIT
33
CS
VOUTB 7
AD5348
32
DB11
VOUTA 1
VOUTB 2
VOUTC 3
VOUTD 4
AGND 5
AGND 6
VOUTE 7
VOUTF 8
VOUTG 9
VOUTH 10
TOP VIEW 31
DB10
(Not to Scale)
30 DB9
VOUTD 9
DB8
28
DB7
VOUTF 12
27
DB6
VOUTG 13
26
DB5
VOUTH 14
25
DB4
DGND 15
24
DB3
BUF 16
23
DB2
LDAC 17
22
DB1
A0 18
21
DB0
A1 19
20
A2
DGND
BUF
LDAC
A0
A1
A2
DB0
DB1
DB2
DB3
29
NOTES
1. EXPOSED PAD. THE EXPOSED PAD MUST BE TIED TO GND.
03331-0-009
AGND 10
VOUTE 11
TOP VIEW
(Not to Scale)
RD
CS
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
11
12
13
14
15
16
17
18
19
20
VOUTC 8
12-BIT
AD5348
30
29
28
27
26
25
24
23
22
21
03331-010
1
VREFEF 2
40
39
38
37
36
35
34
33
32
31
VREFGH
Data Sheet
VREF AB
VDD
VDD
VREF CD
VREF EF
VREF GH
PD
CLR
GAIN
WR
AD5346/AD5347/AD5348
Figure 10. AD5348 Pin Configuration—LFCSP
Figure 9. AD5348 Pin Configuration—TSSOP
Table 7. AD5348 Pin Function Descriptions
Pin No.
TSSOP
LFCSP
1
35
2
36
3
37
4
38, 39
Mnemonic
VREFGH
VREFEF
VREFCD
VDD
5
6 to 9,
11 to 14
10
15
16
17
40
1 to 4,
7 to 10
5, 6
11
12
13
VREFAB
VOUTX
18
19
20
21 to 32
33
14
15
16
17 to 28
29
A0
A1
A2
DB0 to DB11
CS
34
35
36
37
38
Not
applicable
30
31
32
33
34
41
RD
WR
GAIN
CLR
PD
EPAD
AGND
DGND
BUF
LDAC
Description
Reference Input for DACs G and H.
Reference Input for DACs E and F.
Reference Input for DACs C and D.
Power Supply Pin(s). This part can operate from 2.5 V to 5.5 V, and the supply should be decoupled
with a 10 µF capacitor in parallel with a 0.1 µF capacitor to GND. Both VDD pins on the LFCSP
package must be at the same potential.
Reference Input for DACs A and B.
Output of DAC X. Buffered output with rail-to-rail operation.
Analog Ground. Ground reference for analog circuitry.
Digital Ground. Ground reference for digital circuitry.
Buffer Control Pin. Controls whether the reference input to the DAC is buffered or unbuffered.
Active Low Control Input. Updates the DAC registers with the contents of the input registers,
which allows all DAC outputs to be simultaneously updated.
LSB Address Pin. Selects which DAC is to be written to.
Address Pin. Selects which DAC is to be written to.
MSB Address Pin. Selects which DAC is to be written to.
Twelve Parallel Data Inputs. DB11 is the MSB of these 12 bits.
Active Low Chip Select Input. Used in conjunction with WR to write data to the parallel interface,
or with RD to read back data from a DAC.
Active Low Read Input. Used in conjunction with CS to read data back from the internal DACs.
Active Low Write Input. Used in conjunction with CS to write data to the parallel interface.
Gain Control Pin. Controls whether the output range from the DAC is 0 V to VREF or 0 V to 2 × VREF.
Asynchronous Active Low Control Input. Clears all input registers and DAC registers to zeros.
Power-Down Pin. This active low control pin puts all DACs into power-down mode.
Exposed Pad. The exposed pad must be tied to GND.
Rev. A | Page 10 of 24
Data Sheet
AD5346/AD5347/AD5348
TERMINOLOGY
Relative Accuracy
For the DAC, relative accuracy or integral nonlinearity (INL) is
a measure of the maximum deviation, in LSBs, from a straight
line passing through the actual endpoints of the DAC transfer
function. Typical INL versus code plots can be seen in Figure 14,
Figure 15, and Figure 16.
GAIN ERROR
AND
OFFSET
ERROR
ACTUAL
Differential Nonlinearity
Differential nonlinearity (DNL) is the difference between the
measured change and the ideal 1 LSB change between any two
adjacent codes. A specified differential nonlinearity of ± 1 LSB
maximum ensures monotonicity. This DAC is guaranteed
monotonic by design. Typical DNL versus code plots can be
seen in Figure 17, Figure 18, and Figure 19.
OUTPUT
VOLTAGE
IDEAL
DAC CODE
Figure 12. Positive Offset Error and Gain Error
OUTPUT
VOLTAGE
ACTUAL
NEGATIVE
OFFSET
DAC CODE
POSITIVE
GAIN ERROR
NEGATIVE
GAIN ERROR
ACTUAL
GAIN ERROR
AND
OFFSET
ERROR
IDEAL
Offset Error
This is a measure of the offset error of the DAC and the output
amplifier. It is expressed as a percentage of the full-scale range.
If the offset voltage is positive, the output voltage still positive at
zero input code. This is shown in Figure 12. Because the DACs
operate from a single supply, a negative offset cannot appear at
the output of the buffer amplifier. Instead, there is a code close
to zero at which the amplifier output saturates (amplifier
footroom). Below this code there is a dead band over which the
output voltage does not change. This is illustrated in Figure 13.
03331-0-012
POSITIVE
OFFSET
Gain Error
This is a measure of the span error of the DAC, including any
error in the gain of the buffer amplifier. It is the deviation in
slope of the actual DAC transfer characteristic from the ideal
and is expressed as a percentage of the full-scale range. This is
illustrated in Figure 11.
DEADBAND CODES
AMPLIFIER
FOOTROOM
(~1mV)
OUTPUT
VOLTAGE
NEGATIVE
OFFSET
03331-0-013
IDEAL
03331-0-011
DAC CODE
Figure 13. Negative Offset Error and Gain Error
Figure 11. Gain Error
Rev. A | Page 11 of 24
AD5346/AD5347/AD5348
Data Sheet
Offset Error Drift
This is a measure of the change in offset error with changes in
temperature. It is expressed in (ppm of full-scale range)/°C.
Gain Error Drift
This is a measure of the change in gain error with changes in
temperature. It is expressed in (ppm of full-scale range)/°C.
DC Power-Supply Rejection Ratio (PSRR)
This indicates how the output of the DAC is affected by changes
in the supply voltage. PSRR is the ratio of the change in VOUT to
a change in VDD for full-scale output of the DAC. It is measured
in dB. VREF is held at 2 V and VDD is varied ±10%.
DC Crosstalk
This is the dc change in the output level of one DAC at midscale
in response to a full-scale code change (all 0s to all 1s and vice
versa) and output change of another DAC. It is expressed in µV.
Reference Feedthrough
This is the ratio of the amplitude of the signal at the DAC
output to the reference input when the DAC output is not being
updated, that is, LDAC is high. It is expressed in dB.
Channel-to-Channel Isolation
This is a ratio of the amplitude of the signal at the output of one
DAC to a sine wave on the reference inputs of the other DACs.
It is measured by grounding one VREF pin and applying a 10 kHz,
4 V p-p sine wave to the other VREF pins. It is expressed in dB.
Major-Code Transition Glitch Energy
This is the energy of the impulse injected into the analog output
when the DAC changes state. It is normally specified as the area
of the glitch in nV-s and is measured when the digital code is
changed by 1 LSB at the major carry transition (011 . . . 11 to
100 . . . 00 or 100 . . . 00 to 011 . . . 11).
Digital Feedthrough
This is a measure of the impulse injected into the analog output
of the DAC from the digital input pins of the device, but it is
measured when the DAC is not being written to, CS held high.
It is specified in nV-s and is measured with a full-scale change
on the digital input pins, that is, from all 0s to all 1s and vice
versa.
Digital Crosstalk
This is the glitch impulse transferred to the output of one DAC
at midscale in response to a full-scale code change (all 0s to all
1s and vice versa) in the input register of another DAC. It is
expressed in nV-s.
Analog Crosstalk
This is the glitch impulse transferred to the output of one DAC
due to a change in the output of another DAC. It is measured by
loading one of the input registers with a full-scale code change
(all 0s to all 1s and vice versa) while keeping LDAC high. Then
pulse LDAC low and monitor the output of the DAC whose
digital code was not changed. The area of the glitch is expressed
in nV-s.
DAC-to-DAC Crosstalk
This is the glitch impulse transferred to the output of one DAC
due to a digital code change and subsequent output change of
another DAC. This includes both digital and analog crosstalk. It
is measured by loading one of the DACs with a full-scale code
change (all 0s to all 1s and vice versa) with the LDAC pin set
low and monitoring the output of another DAC. The energy of
the glitch is expressed in nV-s.
Multiplying Bandwidth
The amplifiers within the DAC have a finite bandwidth. The
multiplying bandwidth is a measure of this. A sine wave on the
reference (with full-scale code loaded to the DAC) appears on
the output. The multiplying bandwidth is the frequency at
which the output amplitude falls to 3 dB below the input.
Total Harmonic Distortion (THD)
This is the difference between an ideal sine wave and its
attenuated version using the DAC. The sine wave is used as the
reference for the DAC, and the THD is a measure of the
harmonics present on the DAC output. It is measured in dB.
Rev. A | Page 12 of 24
Data Sheet
AD5346/AD5347/AD5348
TYPICAL PERFORMANCE CHARACTERISTICS
0.3
1.0
TA = 25C
VDD = 5V
TA = 25C
VDD = 5V
0.2
DNL ERROR (LSB)
INL ERROR (LSB)
0.5
0
0.1
0
–0.1
–0.5
–1.0
0
50
100
150
200
03331-0-017
03331-0-014
–0.2
–0.3
250
0
50
100
CODE
Figure 14. AD5346 Typical INL Plot
200
250
Figure 17. AD5346 Typical DNL Plot
3
0.6
TA = 25C
VDD = 5V
TA = 25C
VDD = 5V
2
0.4
1
0.2
DNL ERROR (LSB)
0
–1
–3
0
200
400
600
800
–0.2
–0.4
03331-0-015
–2
0
03331-0-018
INL ERROR (LSB)
150
CODE
–0.6
1000
0
200
CODE
400
600
800
1000
CODE
Figure 15. AD5347 Typical INL Plot
Figure 18. AD5347 Typical DNL Plot
12
1.0
TA = 25C
VDD = 5V
TA = 25C
VDD = 5V
8
DNL ERROR (LSB)
0
–4
0
–8
–12
0
1000
2000
CODE
3000
03331-0-019
–0.5
03331-0-016
INL ERROR (LSB)
0.5
4
–1.0
0
4000
1000
2000
CODE
3000
Figure 19. AD5348 Typical DNL Plot
Figure 16. AD5348 Typical INL Plot
Rev. A | Page 13 of 24
4000
AD5346/AD5347/AD5348
Data Sheet
0.2
0.5
VDD = 5V
TA = 25C
0.4
TA = 25C
VREF = 2V
0.1
MAX INL
0.3
0
GAIN ERROR
MAX DNL
ERROR (% FSR)
ERROR (LSB)
0.2
0.1
0
–0.1
MIN DNL
–0.1
–0.2
–0.3
–0.2
MIN INL
–0.4
OFFSET ERROR
–0.4
–0.5
0
1
2
3
4
03331-0-034
03331-0-031
–0.3
–0.5
–0.6
5
0
1
VREF(V)
Figure 20. AD5346 INL and DNL Error vs. VREF
2
3
VDD (V)
4
5
6
Figure 23. Offset Error and Gain Error vs. VDD
5
0.5
VDD = 5V
VREF = 2V
0.4
MAX INL
5V SOURCE
0.3
4
0.2
3
VOUT (V)
ERROR (LSB)
3V SOURCE
MAX DNL
0.1
0
–0.1
2
MIN DNL
–0.2
03331-0-032
1
–0.4
–0.5
–40
MIN INL
–20
0
20
40
60
TEMPERATURE (C)
80
0
100
0
Figure 21. AD5346 INL and DNL Error vs. Temperature
1
2
3
4
SINK/SOURCE CURRENT (mA)
5
6
Figure 24. VOUT Source and Sink Current Capability
1.0
1.0
VDD = 5V
VREF = 2V
0.9
VDD = 5V
TA = 25C
0.8
0.5
0.7
IDD (mA)
0.6
0
OFFSET ERROR
0.4
–20
0
20
40
60
TEMPERATURE (C)
0.2
80
03331-0-036
GAIN ERROR
–1.0
–40
0.5
0.3
–0.5
03331-0-033
ERROR (% FSR)
3V SINK
5V SINK
03331-0-035
–0.3
0.1
0
100
ZERO SCALE
HALF SCALE
DAC CODE
FULL SCALE
Figure 25. Supply Current vs. DAC Code
Figure 22. AD5346 Offset Error and Gain Error vs. Temperature
Rev. A | Page 14 of 24
Data Sheet
1.4
AD5346/AD5347/AD5348
TA = 25°C
VDD = 5V
VREF = 5V
VREF = 2V
GAIN = 1 UNBUFFERED
1.2
TA = –40C
TA = +25C
1.0
VOUTA
IDD (mA)
0.8
TA = +105C
CH1
0.6
LDAC
CH2
03331-0-037
0.2
03331-0-040
0.4
0
2.5
4.5
3.5
4.0
SUPPLY VOLTAGE (V)
3.0
5.0
CH1 1V, CH2 5V, TIME BASE = 1s/DIV
5.5
Figure 26. Supply Current vs. Supply Voltage
Figure 29. Half-Scale Settling (¼ to ¾ Scale Code)
1.0
0.9
TA = 25°C
VDD = 5V
VREF = 2V
TA = 25°C
CH1
0.7
VDD
0.6
0.5
0.4
VOUTA
0.3
CH2
03331-0-041
0.2
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
03331-0-038
0.1
5.5
VDD (V)
CH1 2V, CH2 200mV, TIME BASE = 200s/DIV
Figure 27. Power-Down Current vs. Supply Voltage
Figure 30. Power-On Reset to 0 V
2.5
TA = 25C
VDD = 5V
2.0
VOUT1
CH2
1.5
1.0
PD
VDD = 3V
0
0
1
2
3
VLOGIC (V)
4
03331-0-042
0.5
CH1
03331-0-039
IDD (mA)
IDD POWER-DOWN (A)
0.8
CH1 2.00V, CH2 1.00V, TIME BASE = 20s/DIV
5
Figure 31. Exiting Power-Down to Midscale
Figure 28. Supply Current vs. Logic Input Voltage
Rev. A | Page 15 of 24
AD5346/AD5347/AD5348
Data Sheet
21
0.02
VDD = 5V
TA = 25C
15
FREQUENCY
VDD = 3V
VDD = 5V
12
9
6
0.01
0
–0.01
03331-0-046
FULL-SCALE ERROR (V)
18
0
0.6
0.8
1.0
1.2
03331-0-043
3
1.4
IDD (mA)
–0.02
0
1
2
3
VREF (V)
4
5
6
Figure 35. Full-Scale Error vs. VREF
Figure 32. IDD Histogram with VDD = 3 V and VDD = 5 V
1.999
2.49
1.998
2.48
1.997
2.47
1.996
1s/DIV
10
0
–10
dB
–20
–30
–40
03331-0-045
–60
10
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
Figure 34. Multiplying Bandwidth (Small Signal Frequency Response)
Rev. A | Page 16 of 24
03331-0-047
511
125
150
175
200
225
250
275
300
325
350
375
400
425
450
475
75
100
Figure 36. DAC-to-DAC Crosstalk
Figure 33. AD5348 Major Code Transition Glitch Energy
–50
0
25
50
03331-0-044
VOUT (V)
2.50
Data Sheet
AD5346/AD5347/AD5348
FUNCTIONAL DESCRIPTION
VREF
The AD5346/AD5347/AD5348 are octal resistor-string DACs
fabricated by a CMOS process with resolutions of 8, 10, and 12
bits, respectively. They are written to using a parallel interface.
They operate from single supplies of 2.5 V to 5.5 V, and the
output buffer amplifiers offer rail-to-rail output swing. The gain
of the buffer amplifiers can be set to 1 or 2 to give an output
voltage range of 0 V to VREF or 0 V to 2 × VREF. The AD5346/
AD5347/AD5348 have reference inputs that may be buffered to
draw virtually no current from the reference source. The
devices have a power-down feature that reduces current
consumption to only 100 nA at 3 V.
R
R
R
Figure 38. Resistor String
The architecture of one DAC channel consists of a reference
buffer and a resistor-string DAC followed by an output buffer
amplifier. The voltage at the VREF pin provides the reference
voltage for the DAC. Figure 37 shows a block diagram of the
DAC architecture. Because the input coding to the DAC is
straight binary, the ideal output voltage is given by
D
VOUT VREF N Gain
2
where:
D is the decimal equivalent of the binary code, which is loaded
to the DAC register:
0 to 255 for AD5346 (8 bits)
0 to1023 for AD5347 (10 bits)
0 to 4095 for AD5348 (12 bits)
N is the DAC resolution.
Gain is the output amplifier gain (1 or 2).
VREFAB
REFERENCE
BUFFER
RESISTOR
STRING
OUTPUT
BUFFER AMPLIFIER
The DACs operate with an external reference. The AD5346/
AD5347/AD5348 have a reference input for each pair of DACs.
The reference inputs may be configured as buffered or
unbuffered. This option is controlled by the BUF pin.
In buffered mode (BUF = 1), the current drawn from an
external reference voltage is virtually zero because the impedance is at least 10 MΩ. The reference input range is 1 V to VDD.
In unbuffered mode (BUF = 0), the user can have a reference
voltage as low as 0.25 V and as high as VDD because there is no
restriction due to headroom and footroom of the reference
amplifier. The impedance is still large at typically 90 kΩ for 0 V
to VREF mode and 45 kΩ for 0 V to 2 × VREF mode.
If using an external buffered reference (such as REF192), there
is no need to use the on-chip buffer.
OUTPUT AMPLIFIER
If a gain of +1 is selected (GAIN = 0), the output range is
0.001 V to VREF.
VOUTA
03331-0-020
DAC
REGISTER
DAC REFERENCE INPUT
The output buffer amplifier is capable of generating output
voltages to within 1 mV of either rail. Its actual range depends
on VREF, GAIN, the load on VOUT, and offset error.
(GAIN = +1 OR +2)
INPUT
REGISTER
03331-0-021
R
DIGITAL-TO-ANALOG SECTION
BUF
TO OUTPUT
AMPLIFIER
R
If a gain of +2 is selected (GAIN = +1), the output range is
0.001 V to 2 × VREF. However, because of clamping, the
maximum output is limited to VDD − 0.001 V.
Figure 37. Single DAC Channel Architecture
RESISTOR STRING
The resistor string section is shown in Figure 38. It is simply a
string of resistors, each of value R. The digital code loaded to
the DAC register determines at what node on the string the
voltage is tapped off to be fed into the output amplifier. The
voltage is tapped off by closing one of the switches connecting
the string to the amplifier. Because it is a string of resistors, it is
guaranteed monotonic.
The output amplifier is capable of driving a load of 2 kΩ to
GND or VDD, in parallel with 500 pF to GND or VDD. The
source and sink capabilities of the output amplifier can be seen
in Figure 24.
The slew rate is 0.7 V/μs with a half-scale settling time to ±0.5 LSB
(at 8 bits) of 6 s with the output unloaded. See Figure 29.
PARALLEL INTERFACE
The AD5346/AD5347/AD5348 load their data as a single 8-,
10-, or 12-bit word.
Rev. A | Page 17 of 24
AD5346/AD5347/AD5348
Data Sheet
Double-Buffered Interface
Load DAC Input (LDAC)
The AD5346/AD5347/AD5348 DACs all have double-buffered
interfaces consisting of an input register and a DAC register.
DAC data, BUF, and GAIN inputs are written to the input register under control of the Chip Select (CS) and Write (WR) pins.
LDAC transfers data from the input register to the DAC register,
and therefore updates the outputs. The LDAC function enables
double-buffering of the DAC data, GAIN data, and BUF. There
are two LDAC modes:
Access to the DAC register is controlled by the LDAC function.
When LDAC is high, the DAC register is latched and the input
register may change state without affecting the contents of the
DAC register. However, when LDAC is brought low, the DAC
register becomes transparent and the contents of the input
register are transferred to it. The gain and buffer control signals
are also double-buffered and are updated only when LDAC is
taken low.
This is useful if the user requires simultaneous updating of all
DACs and peripherals. The user can write to all input registers
individually and then, by pulsing the LDAC input low, all
outputs update simultaneously.
These parts contain an extra feature whereby the DAC register
is not updated unless its input register has been updated since
the last time that LDAC was brought low. Normally, when
LDAC is brought low, the DAC registers are filled with the
contents of the input registers. In the case of the AD5346/
AD5347/AD5348, the part updates the DAC register only if the
input register has been changed since the last time the DAC
register was updated. This removes unnecessary crosstalk.
In synchronous mode, the DAC register is updated after
new data is read in on the rising edge of the WR input.
LDAC can be tied permanently low or pulsed as shown in
Figure 3.
In asynchronous mode, the outputs are not updated at the
same time that the input register is written to. When LDAC
goes low, the DAC register is updated with the contents of
the input register.
POWER-ON RESET
The AD5346/AD5347/AD5348 have a power-on reset function,
so that they power up in a defined state. The power-on state is
Normal operation
Reference input buffered
0 V to VREF output range
Output voltage set to 0 V
Both input and DAC registers are filled with zeros and remain
so until a valid write sequence is made to the device. This is
particularly useful in applications where it is important to know
the state of the DAC outputs while the device is powering up.
Clear Input (CLR)
POWER-DOWN MODE
CLR is an active low, asynchronous clear that resets the input
and DAC registers.
The AD5346/AD5347/AD5348 have low power consumption,
dissipating typically 2.4 mW with a 3 V supply and 5 mW with
a 5 V supply. Power consumption can be further reduced when
the DACs are not in use by putting them into power-down
mode, which is selected by taking the PD pin low.
Chip Select Input (CS)
CS is an active low input that selects the device.
Write Input (WR)
WR is an active low input that controls writing of data to the
device. Data is latched into the input register on the rising edge
of WR.
Read Input (RD)
RD is an active low input that controls when data is read back
from the internal DAC registers. On the falling edge of RD, data
is shifted onto the data bus. Under the conditions of a high
capacitive load and high supplies, the user must ensure that the
dynamic current remains at an acceptable level, therefore
ensuring that the die temperature is within specification. The
die temperature can be calculated as
When the PD pin is high, the DACs work normally with a typical power consumption of 1 mA at 5 V (0.8 mA at 3 V). In
power-down mode, however, the supply current falls to 400 nA
at 5 V (120 nA at 3 V) when the DACs are powered down. Not
only does the supply current drop, but the output stage is also
internally switched from the output of the amplifier, making it
open-circuit. This has the advantage that the outputs are threestate while the part is in power-down mode, and provides a
defined input condition for whatever is connected to the outputs
of the DAC amplifiers. The output stage is illustrated in Figure 39.
RESISTOR
STRING DAC
AMPLIFIER
VOUT
where:
IDYNAMIC = cvf (c = capacitance or the data bus, v = VDD, and f =
readback frequency)
Rev. A | Page 18 of 24
POWER-DOWN
CIRCUITRY
Figure 39. Output Stage During Power-Down
03331-0-022
TDIE = TAMBIENT + VDD(IDD + IDYNAMIC)θJA
Data Sheet
AD5346/AD5347/AD5348
The bias generator, the output amplifier, the resistor string, and
all other associated linear circuitry are all shut down when the
power-down mode is activated. However, the contents of the
registers are unaffected when in power-down. The time to exit
power-down is typically 2.5 s for VDD = 5 V and 5 µs when VDD
= 3 V. This is the time from a rising edge on the PD pin to when
the output voltage deviates from its power-down voltage. See
Figure 31.
The AD5347 and AD5348 data bus must be at least 10 and 12
bits wide, respectively, and are best suited to a 16-bit data bus
system.
Examples of data formats for putting GAIN and BUF on a
16-bit data bus are shown in Figure 40. Note that any unused
bits above the actual DAC data may be used for GAIN and BUF.
AD5347
X
X
BUF GAIN DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
X
X
X
X BUF GAIN DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
SUGGESTED DATA BUS FORMATS
X = UNUSED BIT
Figure 40. AD5347/AD5348 Data Format for Word Load with
GAIN and BUF Data on 16-Bit Bus
Table 8. AD5346/AD5347/AD5348 Truth Table
CLR
1
1
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
X
LDAC
1
1
X
1
1
1
1
1
1
1
1
X
X
X
X
X
X
X
X
0
X
CS
1
X
X
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
X
0
WR
X
1
X
0→1
0→1
0→1
0→1
0→1
0→1
0→1
0→1
1
1
1
1
1
1
1
1
X
0
RD
X
1
X
1
1
1
1
1
1
1
1
1→0
1→0
1→0
1→0
1→0
1→0
1→0
1→0
1
0
A2
X
X
X
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
X
X
A1
X
X
X
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
X
X
X = Don’t Care
Rev. A | Page 19 of 24
A0
X
X
X
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
X
X
Function
No data transfer
No data transfer
Clear all registers
Load DAC A input register
Load DAC B input register
Load DAC C input register
Load DAC D input register
Load DAC E input register
Load DAC F input register
Load DAC G input register
Load DAC H input register
Read Back DAC Register A
Read Back DAC Register B
Read Back DAC Register C
Read Back DAC Register D
Read Back DAC Register E
Read Back DAC Register F
Read Back DAC Register G
Read Back DAC Register H
Update DAC registers
Invalid operation
03331-0-048
AD5348
In many applications, the GAIN and BUF pins are hardwired.
However, if more flexibility is required, they can be included in
a data bus. This enables the user to software program GAIN,
giving the option of doubling the resolution in the lower half of
the DAC range. In a bused system, GAIN and BUF may be
treated as data inputs because they are written to the device
during a write operation and take effect when LDAC is taken
low. This means that the reference buffers and the output
amplifier gain of multiple DAC devices can be controlled using
common GAIN and BUF lines. Note that GAIN and BUF are
not read back during an RD operation.
AD5346/AD5347/AD5348
Data Sheet
APPLICATIONS INFORMATION
TYPICAL APPLICATION CIRCUITS
The AD5346/AD5347/AD5348 can be used with a wide range
of reference voltages, especially if the reference inputs are
configured as unbuffered, in which case the devices offer full,
one-quadrant multiplying capability over a reference range of
0.25 V to VDD. More typically, these devices may be used with a
fixed, precision reference voltage. Figure 41 shows a typical
setup for the devices when using an external reference
connected to the reference inputs. Suitable references for 5 V
operation are the AD780, ADR381, and REF192 (2.5 V references). For 2.5 V operation, suitable external references are the
AD589 and the AD1580 (1.2 V band gap references).
BIPOLAR OPERATION USING THE
AD5346/AD5347/AD5348
The AD5346/AD5347/AD5348 have been designed for singlesupply operation, but a bipolar output range is also possible by
using the circuit shown in Figure 42. This circuit has an output
voltage range of ±5 V. Rail-to-rail operation at the amplifier
output is achievable using an AD820, an AD8519, or an OP196
as the output amplifier.
5V
R4
20k
0.1F
VIN
10F
±5V
VDD
EXT
REF
0.1F
VIN
VOUT*
R2
20k
VOUT*
AD5346/AD5347/
AD5348
AD780/ADR381/REF192
WITH VDD = 5V
OR AD589/AD1580 WITH
VDD = 2.5V
–5V
R1
10k
GND
GND
*ONLY ONE CHANNEL OF VREF AND VOUT SHOWN
*ONLY ONE CHANNEL OF VREF AND VOUT SHOWN
03331-0-026
GND
AD5346/AD5347/
AD5348
VDD
VREF*
03331-0-024
VOUT
AD820/AD8519/
OP196
VREF*
VOUT
GND
EXT
REF
+5V
R3
10k
VDD = 2.5V to 5.5V
0.1F
10F
Figure 42. Bipolar Operation with the AD5346/AD5347/AD5348
The output voltage for any input code can be calculated as
follows:
Figure 41. AD5346/AD5347/AD5348 Using an External Reference
VOUT = [(1 + R4/R3) × (R2/(R1 + R2) × (2 × VREF × D/2N)] −
R4 × VREF/R3
where:
D is the decimal equivalent of the code loaded to the DAC.
N is the DAC resolution.
VREF is the reference voltage input.
with:
VREF = 5 V
R1 = R3 = 10 kΩ
R2 = R4 = 20 kΩ
VDD = 5 V
GAIN = 2
VOUT = (10 × D/2N) – 5
Rev. A | Page 20 of 24
Data Sheet
AD5346/AD5347/AD5348
5V
DECODING MULTIPLE AD5346/AD5347/AD5348s
The 74HC139 is used as a 2-line to 4-line decoder to address
any of the DACs in the system. To prevent timing errors from
occurring, the enable input should be brought to its inactive
state while the coded address inputs are changing state.
Figure 43 shows a diagram of a typical setup for decoding
multiple devices in a system. Once data has been written
sequentially to all DACs in a system, all the DACs can be
updated simultaneously using a common LDAC line. A common CLR line can also be used to reset all DAC outputs to 0 V.
AD5346/AD5347
A0 /AD5348
A1
A2
WR
DATA
INPUTS
LD AC
CLR
CS
VIN
VDD
ENABLE
CODED
ADDRESS
1G
VCC
1A
74HC139
1B
1Y0
AD5346/AD5347
A0 /AD5348
1Y1
A1
A2
WR
LD AC
CLR
CS
1Y2
1Y3
DGND
DATA BUS
AD5346/AD5347
A0 /AD5348
A1
A2
WR
DATA
LD AC
INPUTS
CLR
CS
VREFAB
1k
FAIL
PASS
VDD
PASS/
FAIL
1/2
CMP04
AD5346/AD5347/
AD5348
VOUTB
03331-0-028
VOUTA
1/6 74HC05
GND
Figure 44. Programmable Window Detector
PROGRAMMABLE CURRENT SOURCE
Figure 45 shows the AD5346/AD5347/AD5348 used as the
control element of a programmable current source. In this
example, the full-scale current is set to 1 mA. The output
voltage from the DAC is applied across the current setting
resistor of 4.7 kΩ in series with the 470 Ω adjustment
potentiometer, which gives an adjustment of about ±5%.
Suitable transistors to place in the feedback loop of the amplifier include the BC107 and the 2N3904, which enable the
current source to operate from a minimum VSOURCE of 6 V. The
operating range is determined by the operating characteristics
of the transistor. Suitable amplifiers include the AD820 and the
OP295, both having rail-to-rail operation on their outputs. The
current for any digital input code and resistor value can be
calculated as follows:
I G VREF
D
mA
(2N R)
where:
G is the gain of the buffer amplifier (1 or 2).
D is the digital input code.
N is the DAC resolution (8, 10, or 12 bits).
R is the sum of the resistor plus adjustment potentiometer in kΩ.
DATA
INPUTS
AD5346/AD5347
VDD = 5V
03331-0-027
A0 /AD5348
A1
A2
WR
DATA
INPUTS
LD AC
CLR
CS
VREF
1k
0.1F
10F
VSOURCE
Figure 43. Decoding Multiple DAC Devices
VIN
AD5346/AD5347/AD5348 AS DIGITALLY
PROGRAMMABLE WINDOW DETECTORS
A digitally programmable upper/lower limit detector using two
of the DACs in the AD5346/AD5347/AD5348 is shown in
Figure 44. Any pair of DACs in the device may be used, but for
simplicity the description refers to DACs A and B.
5V
VDD
EXT
REF
VREF*
VOUT
GND
0.1F
LOAD
VOUT*
AD5346/AD5347/
AD5348
4.7k
GND
The upper and lower limits for the test are loaded to DACs A
and B which, in turn, set the limits on the CMP04. If a signal at
the VIN input is not within the programmed window, an LED
indicates the fail condition.
470
*ONLY ONE CHANNEL OF VREF AND VOUT SHOWN
Rev. A | Page 21 of 24
Figure 45. Programmable Current Source
03331-0-029
A0
A1
A2
WR
LDAC
CLR
10F
0.1F
The CS pin on these devices can be used in applications to
decode a number of DACs. In this application, all DACs in the
system receive the same data and WR pulses, but only the CS to
one of the DACs will be active at any one time, so data will only
be written to the DAC whose CS is low.
AD5346/AD5347/AD5348
Data Sheet
COARSE AND FINE ADJUSTMENT USING THE
AD5346/AD5347/AD5348
POWER SUPPLY BYPASSING AND GROUNDING
Two of the DACs in the AD5346/AD5347/AD5348 can be
paired together to form a coarse and fine adjustment function,
as shown in Figure 46. As with the window comparator
previously described, the description refers to DACs A and B.
DAC A provides the coarse adjustment, while DAC B provides
the fine adjustment. Varying the ratio of R1 and R2 changes the
relative effect of the coarse and fine adjustments. With the
resistor values shown, the output amplifier has unity gain for
the DAC A output, so the output range is 0 V to (VREF – 1 LSB).
For DAC B, the amplifier has a gain of 7.6 × 10–3, giving DAC B
a range equal to 2 LSBs of DAC A.
The circuit is shown with a 2.5 V reference, but reference
voltages up to VDD may be used. The op amps indicated allow a
rail-to-rail output swing.
VDD = 5V
0.1F
10F
VDD
VOUT
VREFAB
0.1F
AD5346/AD5347/
AD5348
VOUTB
R1
390
R2
51.2k
AD780/ADR381/REF192
WITH VDD = 5V
GND
Figure 46. Coarse and Fine Adjustment
03331-0-030
VOUTA
VOUT
GND
R3
51.2k
5V
VIN
EXT
REF
R4
390
In any circuit where accuracy is important, careful consideration
of the power supply and ground return layout helps to ensure
the rated performance.
The printed circuit board on which the AD5346/AD5347/AD5348
is mounted should be designed so that the analog and digital
sections are separated and are confined to certain areas of the
board. This facilitates the use of ground planes that can be
separated easily. A minimum etch technique is generally best
for ground planes because it gives the best shielding. Digital and
analog ground planes should be joined in one place only. If the
AD5346/AD5347/AD5348 is the only device requiring an
AGND-to-DGND connection, then the ground planes should
be connected at the AGND and DGND pins of the AD5346/
AD5347/AD5348. If the AD5346/AD5347/AD5348 is in a
system where multiple devices require AGND-to-DGND
connections, the connection should be made at one point only,
a star ground point that should be established as close as
possible to the AD5346/AD5347/AD5348.
The AD5346/AD5347/AD5348 should have ample supply
bypassing of 10 μF in parallel with 0.1 μF on the supply located
as close to the package as possible, ideally right up against the
device. The 10 μF capacitors are the tantalum bead type. The
0.1 μF capacitor should have low effective series resistance
(ESR) and effective series inductance (ESI), such as the
common ceramic types that provide a low impedance path to
ground at high frequencies to handle transient currents due to
internal logic switching.
The power supply lines of the device should use the largest trace
possible to provide low impedance paths and to reduce the
effects of glitches on the power supply line. Fast switching
signals such as clocks should be shielded with digital ground to
avoid radiating noise to other parts of the board, and should
never be run near the reference inputs. Avoid crossover of
digital and analog signals. Traces on opposite sides of the board
should run at right angles to each other to reduce the effects of
feedthrough through the board. A microstrip technique is by far
the best, but not always possible with a double-sided board. In
this technique, the component side of the board is dedicated to
ground plane, while signal traces are placed on the solder side.
Rev. A | Page 22 of 24
Data Sheet
AD5346/AD5347/AD5348
OUTLINE DIMENSIONS
9.80
9.70
9.60
20
38
4.50
4.40
4.30
6.40 BSC
1
19
PIN 1
1.20
MAX
0.15
0.05
COPLANARITY
0.10
0.50
BSC
0.27
0.17
SEATING
PLANE
0.20
0.09
8°
0°
0.70
0.60
0.45
COMPLIANT TO JEDEC STANDARDS MO-153-BD-1
Figure 47. 38-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-38)
Dimensions shown in millimeters
0.30
0.25
0.18
31
40
30
0.50
BSC
1
TOP VIEW
0.80
0.75
0.70
SEATING
PLANE
4.25
4.10 SQ
3.95
EXPOSED
PAD
21
0.45
0.40
0.35
10
11
20
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
BOTTOM VIEW
0.25 MIN
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
COMPLIANT TO JEDEC STANDARDS MO-220-WJJD.
Figure 48. 40-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
6 mm × 6 mm, Very Very Thin Quad
(CP-40-9)
Dimensions shown in millimeters
Rev. A | Page 23 of 24
PIN 1
INDICATOR
05-06-2011-A
PIN 1
INDICATOR
6.10
6.00 SQ
5.90
AD5346/AD5347/AD5348
Data Sheet
ORDERING GUIDE
Model1
AD5346BRU
AD5346BRU-REEL7
AD5346BRUZ
AD5346BRUZ-REEL
AD5346BRUZ-REEL7
AD5346BCPZ
AD5347BRU
AD5347BRU-REEL7
AD5347BRUZ
AD5347BCPZ
AD5348BRU
AD5348BRUZ
AD5348BCPZ
1
Temperature Range
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
Package Description
38-Lead Thin Shrink Small Outline Package [TSSOP]
38-Lead Thin Shrink Small Outline Package [TSSOP]
38-Lead Thin Shrink Small Outline Package [TSSOP]
38-Lead Thin Shrink Small Outline Package [TSSOP]
38-Lead Thin Shrink Small Outline Package [TSSOP]
40-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
38-Lead Thin Shrink Small Outline Package [TSSOP]
38-Lead Thin Shrink Small Outline Package [TSSOP]
38-Lead Thin Shrink Small Outline Package [TSSOP]
40-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
38-Lead Thin Shrink Small Outline Package [TSSOP]
38-Lead Thin Shrink Small Outline Package [TSSOP]
40-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
Z = RoHS Compliant Part.
©2003–2015 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D03331-0-6/15(A)
Rev. A | Page 24 of 24
Package Option
RU-38
RU-38
RU-38
RU-38
RU-38
CP-40-9
RU-38
RU-38
RU-38
CP-40-9
RU-38
RU-38
CP-40-9
工商网监
湘ICP备2023018690号
