DAC7718
DA
C
771
8
DA
C7
71
8
www.ti.com
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
Octal, 12-Bit, Low-Power, High-Voltage Output, Serial Input
DIGITAL-TO-ANALOG CONVERTER
Check for Samples: DAC7718
FEATURES
DESCRIPTION
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The DAC7718 is a low-power, octal, 12-bit
digital-to-analog converter (DAC). With a 5V
reference, the output can either be a bipolar ±15V
voltage when operating from dual ±15.5V (or higher)
power supplies, or a unipolar 0V to +30V voltage
when operating from a +30.5V (or higher) power
supply. With a 5.5V reference, the output can either
be a bipolar ±16.5V voltage when operating from dual
±17V (or higher) power supplies, or a unipolar 0V to
+33V voltage when operating from a +33.5V (or
higher) power supply. This DAC provides low-power
operation, good linearity, and low glitch over the
specified temperature range of –40°C to +105°C. This
device is trimmed in manufacturing and has very low
zero-code and gain error. In addition, system level
calibration can be performed over the entire signal
chain. The output range can be offset by using the
DAC offset register.
1
2345
Bipolar Output: ±2V to ±16.5V
Unipolar Output: 0V to +33V
12-Bit Resolution
Low Power: 14.4mW/Ch (Bipolar Supply)
Relative Accuracy: 1 LSB Max
Low Zero/Full-Scale Error: ±1 LSB Max
Flexible System Calibration
Low Glitch: 4nV-s
Settling Time: 15ms
Channel Monitor Output
Programmable Gain: x4/x6
Programmable Offset
SPI™: Up to 50MHz, 1.8V/3V/5V Logic
Schmitt Trigger Inputs
Daisy-Chain with Sleep Mode Enhancement
Packages: QFN-48 (7x7mm), TQFP-64
(10x10mm)
APPLICATIONS
•
•
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Automatic Test Equipment
PLC and Industrial Process Control
Communications
IOVDD
DGND
DVDD
AVDD
AVSS
REF-A
DAC7718
Analog Monitor
The DAC7718 features a standard, high-speed serial
peripheral interface (SPI) that operates at up to
50MHz and is 1.8V, 3V, and 5V logic compatible, to
communicate with a DSP or microprocessor. The
input data of the device are double-buffered. An
asynchronous load input (LDAC) transfers data from
the DAC data register to the DAC latch. The
asynchronous CLR input sets the output of all eight
DACs to AGND. The VMON pin is a monitor output
that connects to the individual analog outputs, the
offset DAC, the reference buffer outputs, and two
external inputs through a multiplexer (mux).
SCLK
CS
SDI
SDO
RST
RSTSEL
LDAC
CLR
USB/BTC
GPIO-0
GPIO-1
GPIO-2
Control Logic
Reference
Buffer A
OFFSET
DAC A
Command
Registers
To DAC-0, DAC-1,
DAC-2, DAC-3
(When Correction Engine Disabled)
Input Data
Register 0
Correction
Engine
VOUT-7
AIN-0
AIN-1
Ref Buffer A
Ref Buffer B
OFFSET-B
VMON
The DAC7718 is pin-to-pin and function-compatible
with the DAC8718 (16-bit) and the DAC8218 (14-bit).
OFFSET-A
DAC-0
DAC-0
Data
Mux
WAKEUP
SPI Shift Register
VOUT-0
VOUT-0
Latch-0
To DAC-0, DAC-1,
DAC-2, DAC-3
Internal Trimming
Zero/Gain; INL
LDAC
User Calibration:
Zero Register 0
Gain Regsiter 0
AGND-A
To DAC-4, DAC-5, DAC-6, DAC-7
OFFSET-B
Reference
Buffer B
(Same Function Blocks
for All Channels)
AIN-0
OFFSET
DAC B
AGND-B
Power-Up/
Power-Down
Control
VOUT-7
AIN-1
DGND
DVDD
AVDD
AVSS
REF-B
1
2
3
4
5
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
DSP is a trademark of Texas Instruments.
SPI, QSPI are trademarks of Motorola Inc.
Microwire is a trademark of National Semiconductor.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2009, Texas Instruments Incorporated
DAC7718
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ORDERING INFORMATION (1)
PRODUCT
RELATIVE
ACCURACY
(LSB)
DIFFERENTIAL
LINEARITY
(LSB)
±1
±1
DAC7718
(1)
PACKAGELEAD
PACKAGE
DESIGNATOR
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKING
±1
QFN-48
RGZ
–40°C to +105°C
DAC7718
±1
TQFP-64
PAG
–40°C to +105°C
DAC7718
For the most current package and ordering information, see the Package Option Addendum at the end of this data sheet, or see the TI
web site at www.ti.com.
ABSOLUTE MAXIMUM RATINGS (1)
Over operating free-air temperature range (unless otherwise noted).
DAC7718
UNIT
AVDD to AVSS
–0.3 to 38
V
AVDD to AGND
–0.3 to 38
V
AVSS to AGND, DGND
–19 to 0.3
V
DVDD to DGND
–0.3 to 6
V
IOVDD to DGND
–0.3 to min of (6 or DVDD + 0.3)
V
–0.3 to 0.3
V
Digital input voltage to DGND
–0.3 to IOVDD + 0.3
V
SDO to DGND
–0.3 to IOVDD + 0.3
V
VOUT-x, VMON, AIN-x to AVSS
–0.3 to AVDD + 0.3
V
–0.3 to DVDD
V
AGND-x to DGND
REF-A, REF-B to AGND
GPIO-n to DGND
–0.3 to IOVDD + 0.3
V
GPIO-n input current
5
mA
Maximum current from VMON
3
mA
Operating temperature range
–40 to +105
°C
Storage temperature range
–65 to +150
°C
Maximum junction temperature (TJ max)
+150
°C
2.5
kV
Charged device model (CDM)
1000
V
Machine model (MM)
200
V
TQFP
55
°C/W
QFN
27.5
°C/W
TQFP
21
°C/W
QFN
10.8
°C/W
(TJ max – TA) / qJA
W
Human body model (HBM)
ESD ratings
Junction-to-ambient, qJA
Thermal impedance
Junction-to-case, qJC
Power dissipation
(1)
2
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to absolute
maximum conditions for extended periods may affect device reliability.
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Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s): DAC7718
DAC7718
www.ti.com
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
ELECTRICAL CHARACTERISTICS: Dual-Supply
All specifications at TA = TMIN to TMAX, AVDD = +16.5V, AVSS = –16.5V, IOVDD = DVDD = +5V, REF-A and REF-B = +5V,
gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values (1),
unless otherwise noted.
DAC7718
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
STATIC PERFORMANCE (2)
Resolution
12
Bits
Linearity error
Measured by line passing through codes 000h and FFFh
±1
LSB
Differential linearity error
Measured by line passing through codes 000h and FFFh
±1
LSB
Bipolar zero error
TA = +25°C, gain = 4 or 6, code = 800h
±1
LSB
Bipolar zero error TC
Gain = 4 or 6, code = 800h
±2
ppm FSR/°C
TA = +25°C, gain = 6, code = 000h
±1
LSB
TA = +25°C, gain = 4, code = 000h
±1
LSB
±3
ppm FSR/°C
TA = +25°C, gain = 6
±1
LSB
TA = +25°C, gain = 4
±1
LSB
±3
ppm FSR/°C
±1
LSB
±3
ppm FSR/°C
Zero-code error
Zero-code error TC
Gain error
Gain = 4 or 6, code = 000h
±0.5
±0.5
Gain error TC
Gain = 4 or 6
Full-scale error
TA = +25°C, gain = 4 or 6, code = FFFh
Full-scale error TC
Gain = 4 or 6, code = FFFh
±0.5
Measured channel at code = 800h, full-scale change on any
other channel
0.05
DC crosstalk
(1)
(2)
(3)
(3)
±1
LSB
Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the error for symmetrical output. The default value may vary
no more than ±1 LSB from the nominal number listed in Table 7. The Offset DAC pins are not intended to drive an external load, and
must not be connected during dual-supply operation.
Gain = 4 and TC specified by design and characterization.
The DAC outputs are buffered by op amps that share common AVDD and AVSS power supplies. DC crosstalk indicates how much dc
change in one or more channel outputs may occur when the dc load current changes in one channel (because of an update). With
high-impedance loads, the effect is virtually immeasurable. Multiple AVDD and AVSS terminals are provided to minimize dc crosstalk.
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DAC7718
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
www.ti.com
ELECTRICAL CHARACTERISTICS: Dual-Supply (continued)
All specifications at TA = TMIN to TMAX, AVDD = +16.5V, AVSS = –16.5V, IOVDD = DVDD = +5V, REF-A and REF-B = +5V,
gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values (1),
unless otherwise noted.
DAC7718
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
V
ANALOG OUTPUT (VOUT-0 to VOUT-7) (4)
Voltage output (5)
Output impedance
VREF = +5V
–15
+15
VREF = +1.5V
–4.5
+4.5
V
0.5
Ω
Code = 800h
Short-circuit current (6)
Load current
Output drift vs time
±8
±3
mA
TA = +25°C, device operating for 500 hours, full-scale output
3.4
ppm of FSR
TA = +25°C, device operating for 1000 hours, full-scale output
4.3
Capacitive load stability
Settling time
Slew rate
ppm of FSR
500
pF
To 0.03% of FSR, CL = 200pF, RL= 10kΩ, code from 000h to
FFFh and FFFh to 000h
10
ms
To 1 LSB, CL = 200pF, RL = 10kΩ, code from 000h to FFFh
and FFFh to 000h
15
ms
To 1 LSB, CL = 200pF, RL = 10kΩ, code from 7F0h to 810h
and 810h to 7F0h
6
ms
6
V/ms
(7)
Power-on delay (8)
mA
See Figure 37
From IOVDD ≥ +1.8V and DVDD ≥ +2.7V to CS low
Power-down recovery time
200
ms
60
ms
4
nV-s
5
mV
Digital-to-analog glitch (9)
Code from 7FFh to 800h and 800h to 7FFh
Glitch impulse peak amplitude
Code from 7FFh to 800h and 800h to 7FFh
Channel-to-channel isolation (10)
VREF = 4VPP, f = 1kHz
88
dB
DACs in the same group
7.5
nV-s
DAC-to-DAC crosstalk (11)
1
nV-s
Digital crosstalk (12)
1
nV-s
Digital feedthrough (13)
1
Output noise
DACs among different groups
200
nV/√Hz
TA = +25°C at 10kHz, gain = 4
130
nV/√Hz
20
mVPP
0.05
LSB
0.1Hz to 10Hz, gain = 6
Power-supply rejection (14)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
4
nV-s
TA = +25°C at 10kHz, gain = 6
AVDD = ±15.5V to ±16.5V
Specified by design.
The analog output range of VOUT-0 to VOUT-7 is equal to (6 × VREF – 5 × OUTPUT_OFFSET_DAC) for gain = 6. The maximum value of
the analog output must not be greater than (AVDD – 0.5V), and the minimum value must not be less than (AVSS + 0.5V). All
specifications are for a ±16.5V power supply and a ±15V output, unless otherwise noted.
When the output current is greater than the specification, the current is clamped at the specified maximum value.
Slew rate is measured from 10% to 90% of the transition when the output changes from 0 to full-scale.
Power-on delay is defined as the time from when the supply voltages reach the specified conditions to when CS goes low, for valid
digital communication.
Digital-to-analog glitch is defined as the amount of energy injected into the analog output at the major code transition. It is specified as
the area of the glitch in nV-s. It is measured by toggling the DAC register data between 7FFh and 800h in straight binary format.
Channel-to-channel isolation refers to the ratio of the signal amplitude at the output of one DAC channel to the amplitude of the
sinusoidal signal on the reference input of another DAC channel. It is expressed in dB and measured at midscale.
DAC-to-DAC crosstalk is the glitch impulse that appears at the output of one DAC as a result of both the full-scale digital code and
subsequent analog output change at another DAC. It is measured with LDAC tied low and expressed in nV-s.
Digital crosstalk is the glitch impulse transferred to the output of one converter as a result of a full-scale code change in the DAC input
register of another converter. It is measured when the DAC output is not updated, and is expressed in nV-s.
Digital feedthrough is the glitch impulse injected to the output of a DAC as a result of a digital code change in the DAC input register of
the same DAC. It is measured with the full-scale digital code change without updating the DAC output, and is expressed in nV-s.
The output must not be greater than (AVDD – 0.5V) and not less than (AVSS + 0.5V).
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Product Folder Link(s): DAC7718
DAC7718
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
ELECTRICAL CHARACTERISTICS: Dual-Supply (continued)
All specifications at TA = TMIN to TMAX, AVDD = +16.5V, AVSS = –16.5V, IOVDD = DVDD = +5V, REF-A and REF-B = +5V,
gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values (1),
unless otherwise noted.
DAC7718
PARAMETER
OFFSET DAC OUTPUT (15)
CONDITIONS
MIN
TYP
MAX
UNIT
(16)
Voltage output
VREF = +5V
Full-scale error
TA = +25°C
0
±0.25
LSB
Zero-code error
TA = +25°C
±0.25
LSB
Linearity error
5
±0.5
Differential linearity error
V
LSB
±1
LSB
ANALOG MONITOR PIN (VMON)
Output impedance (17)
TA = +25°C
Three-state leakage current
2
kΩ
100
nA
AUXILIARY ANALOG INPUT
Input range
AVSS
Input impedance
(AIN-x to VMON)
Input capacitance
TA = +25°C
AVDD
V
2
(15)
Input leakage current
kΩ
4
pF
30
nA
REFERENCE INPUT
Reference input voltage range (18)
1.0
5.5
V
Reference input dc impedance
10
MΩ
Reference input capacitance (15)
10
pF
DIGITAL INPUT (15)
High-level input voltage, VIH
Low-level input voltage, VIL
Input current
IOVDD = +4.5V to +5.5V
3.8
0.3 + IOVDD
V
IOVDD = +2.7V to +3.3V
2.3
0.3 + IOVDD
V
IOVDD = +1.7V to 2.0V
1.5
0.3 + IOVDD
V
IOVDD = +4.5V to +5.5V
–0.3
0.8
V
IOVDD = +2.7V to +3.3V
–0.3
0.6
V
IOVDD = +1.7V to 2.0V
–0.3
0.3
V
±1
mA
±5
mA
CLR, LDAC, RST, CS, and SDI
USB/BTC, RSTSEL, and GPIO-n
CLR, LDAC, RST, CS, and SDI
Input capacitance
5
pF
USB/BTC and RSTSEL
12
pF
GPIO-n
14
pF
DIGITAL OUTPUT (15)
High-level output voltage, VOH
(SDO)
IOVDD = +2.7V to +5.5V, sourcing 1mA
IOVDD – 0.4
IOVDD
V
1.6
IOVDD
V
Low-level output voltage, VOL
(SDO)
IOVDD = +2.7V to +5.5V, sinking 1mA
0
0.4
V
IOVDD = +1.8V, sinking 200mA
0
0.2
V
GPIO-n output voltage low, VOL
1mA sink from IOVDD
GPIO-n output voltage high, VOH
10kΩ pull-up resistor to IOVDD
High-impedance leakage current
SDO and GPIO-n
High-impedance output
capacitance
SDO
IOVDD = +1.8V, sourcing 200mA
GPIO-n
0.15
V
±5
mA
5
pF
14
pF
0.99 × IOVDD
V
(15) Specified by design.
(16) Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the error for symmetrical output. The default value may vary
no more than ±1 LSB from the nominal number listed in Table 7. The Offset DAC pins are not intended to drive an external load, and
must not be connected during dual-supply operation.
(17) 8kΩ when VMON is connected to Reference Buffer A or B, and 4kΩ when VMON is connected to Offset DAC-A or -B.
(18) Reference input voltage ≤ DVDD.
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DAC7718
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
www.ti.com
ELECTRICAL CHARACTERISTICS: Dual-Supply (continued)
All specifications at TA = TMIN to TMAX, AVDD = +16.5V, AVSS = –16.5V, IOVDD = DVDD = +5V, REF-A and REF-B = +5V,
gain = 6, AGND-x = DGND = 0V, data format = straight binary, and Offset DAC A and Offset DAC B are at default values (1),
unless otherwise noted.
DAC7718
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
POWER SUPPLY
AVDD
+4.5
+18
V
AVSS
–18
–4.5
V
DVDD
+2.7
+5.5
V
IOVDD (19)
+1.8
+5.5
Normal operation, midscale code, output unloaded
AIDD
4.3
Power down, output unloaded
DIDD
IOIDD
Power dissipation
V
mA
35
mA
–2.7
mA
Power down, output unloaded
35
mA
Normal operation
78
mA
Power down
36
mA
Normal operation, VIH = IOVDD, VIL = DGND
5
mA
Power down, VIH = IOVDD, VIL = DGND
5
Normal operation, midscale code, output unloaded
AISS
6
–4
Normal operation, ±16.5V supplies, midscale code
115
mA
165
mW
+105
°C
TEMPERATURE RANGE
Specified performance
–40
(19) IOVDD ≤ DVDD.
6
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DAC7718
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
ELECTRICAL CHARACTERISTICS: Single-Supply
All specifications at TA = TMIN to TMAX, AVDD = +32V, AVSS = 0V, IOVDD = DVDD = +5V, REF-A and REF-B = +5V, gain = 6,
AGND-x = DGND = 0V, data format = straight binary, and OFFSET-A = OFFSET-B = AGND, unless otherwise noted.
DAC7718
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
STATIC PERFORMANCE (1)
Resolution
12
Bits
Linearity error
Measured by line passing through codes 010h and FFFh
±1
LSB
Differential linearity error
Measured by line passing through codes 010h and FFFh
±1
LSB
Unipolar zero error
TA = +25°C, gain = 4 or 6, code = 010h
±1
LSB
Unipolar zero error TC
Gain = 4 or 6, code = 010h
±3
ppm FSR/°C
TA = +25°C, gain = 6
±1
LSB
TA = +25°C, gain = 4
±1
LSB
±3
ppm FSR/°C
Gain error
±0.5
Gain error TC
Gain = 4 or 6
Full-scale error
TA = +25°C, gain = 4 or 6, code = FFFh
Full-scale error TC
Gain = 4 or 6, code = FFFh
±0.5
DC crosstalk (2)
Measured channel at code = 800h, full-scale change on any
other channel
0.05
ANALOG OUTPUT (VOUT-0 to VOUT-7)
Voltage output (4)
Output impedance
±1
Output drift vs time
0
+30
0
+9
V
0.5
Ω
Code = 800h
±8
mA
TA = +25°C, device operating for 500 hours, full-scale output
3.4
ppm of FSR
TA = +25°C, device operating for 1000 hours, full-scale output
4.3
10
ms
To 1 LSB, CL = 200pF, RL = 10kΩ, code from 010h to FFFh
and FFFh to 010h
15
ms
To 1 LSB, CL = 200pF, RL = 10kΩ, code from 7F0h to 810h
and 810h to 7F0h
6
ms
6
V/ms
From IOVDD ≥ +1.8V and DVDD ≥ +2.7V to CS low
Code from 7FFh to 800h and 800h to 7FFh
Channel-to-channel isolation (9)
VREF = 4VPP, f = 1kHz
(9)
pF
To 0.03% of FSR, CL = 200pF, RL= 10kΩ, code from 010h to
FFFh and FFFh to 010h
Glitch impulse peak amplitude
(8)
ppm of FSR
500
Code from 7FFh to 800h and 800h to 7FFh
(5)
(6)
(7)
mA
±3
Digital-to-analog glitch (8)
(3)
(4)
V
See Figure 84 and Figure 85
Power-down recovery time
(1)
(2)
LSB
VREF = +1.5V
Slew rate (6)
Power-on delay (7)
ppm FSR/°C
VREF = +5V
Capacitive load stability
Settling time
LSB
±3
(3)
Short-circuit current (5)
Load current
±1
200
ms
90
ms
4
nV-s
5
mV
88
dB
Gain = 4 and TC specified by design and characterization.
The DAC outputs are buffered by op amps that share common AVDD and AVSS power supplies. DC crosstalk indicates how much dc
change in one or more channel outputs may occur when the dc load current changes in one channel (because of an update). With
high-impedance loads, the effect is virtually immeasurable. Multiple AVDD and AVSS terminals are provided to minimize dc crosstalk.
Specified by design.
The analog output range of VOUT-0 to VOUT-7 is equal to (6 × VREF) for gain = 6. The maximum value of the analog output must not be
greater than (AVDD – 0.5V). All specifications are for a +32V power supply and a 0V to +30V output, unless otherwise noted.
When the output current is greater than the specification, the current is clamped at the specified maximum value.
Slew rate is measured from 10% to 90% of the transition when the output changes from 0 to full-scale.
Power-on delay is defined as the time from when the supply voltages reach the specified conditions to when CS goes low, for valid
digital communication.
Digital-to-analog glitch is defined as the amount of energy injected into the analog output at the major code transition. It is specified as
the area of the glitch in nV-s. It is measured by toggling the DAC register data between 7FFh and 800h in straight binary format.
Channel-to-channel isolation refers to the ratio of the signal amplitude at the output of one DAC channel to the amplitude of the
sinusoidal signal on the reference input of another DAC channel. It is expressed in dB and measured at midscale.
Submit Documentation Feedback
Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s): DAC7718
7
DAC7718
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
www.ti.com
ELECTRICAL CHARACTERISTICS: Single-Supply (continued)
All specifications at TA = TMIN to TMAX, AVDD = +32V, AVSS = 0V, IOVDD = DVDD = +5V, REF-A and REF-B = +5V, gain = 6,
AGND-x = DGND = 0V, data format = straight binary, and OFFSET-A = OFFSET-B = AGND, unless otherwise noted.
DAC7718
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
10
nV-s
1
nV-s
Digital crosstalk (11)
1
nV-s
Digital feedthrough (12)
1
DAC-to-DAC crosstalk (10)
Output noise
DACs in the same group
DACs among different groups
200
nV/√Hz
TA = +25°C at 10kHz, gain = 4
130
nV/√Hz
20
mVPP
0.05
LSB
0.1Hz to 10Hz, gain = 6
Power-supply rejection (13)
nV-s
TA = +25°C at 10kHz, gain = 6
AVDD = +33V to +36V
ANALOG MONITOR PIN (VMON)
Output impedance (14)
TA = +25°C
Three-state leakage current
2
kΩ
100
nA
AUXILIARY ANALOG INPUT
Input range
Input impedance
(AIN-x to VMON)
AVSS
TA = +25°C
AVDD
2
V
kΩ
Input capacitance (15)
4
pF
Input leakage current
30
nA
REFERENCE INPUT
Reference input voltage
range (16)
1.0
5.5
V
Reference input dc impedance
10
MΩ
Reference input capacitance (15)
10
pF
DIGITAL INPUT (15)
High-level input voltage, VIH
Low-level input voltage, VIL
Input current
IOVDD = +4.5V to +5.5V
3.8
0.3 + IOVDD
V
IOVDD = +2.7V to +3.3V
2.3
0.3 + IOVDD
V
IOVDD = +1.7V to 2.0V
1.5
0.3 + IOVDD
V
IOVDD = +4.5V to +5.5V
–0.3
0.8
V
IOVDD = +2.7V to +3.3V
–0.3
0.6
V
IOVDD = +1.7V to 2.0V
–0.3
0.3
V
±1
mA
±5
mA
CLR, LDAC, RST, CS, and SDI
USB/BTC, RSTSEL, and GPIO-n
CLR, LDAC, RST, CS, and SDI
Input capacitance
5
pF
USB/BTC and RSTSEL
12
pF
GPIO-n
14
pF
(10) DAC-to-DAC crosstalk is the glitch impulse that appears at the output of one DAC as a result of both the full-scale digital code and
subsequent analog output change at another DAC. It is measured with LDAC tied low and expressed in nV-s.
(11) Digital crosstalk is the glitch impulse transferred to the output of one converter as a result of a full-scale code change in the DAC input
register of another converter. It is measured when the DAC output is not updated, and is expressed in nV-s.
(12) Digital feedthrough is the glitch impulse injected to the output of a DAC as a result of a digital code change in the DAC input register of
the same DAC. It is measured with the full-scale digital code change without updating the DAC output, and is expressed in nV-s.
(13) The analog output must not be greater than (AVDD – 0.5V).
(14) 8kΩ when VMON is connected to Reference Buffer A or B, and 4kΩ when VMON is connected to Offset DAC-A or -B.
(15) Specified by design.
(16) Reference input voltage ≤ DVDD.
8
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ELECTRICAL CHARACTERISTICS: Single-Supply (continued)
All specifications at TA = TMIN to TMAX, AVDD = +32V, AVSS = 0V, IOVDD = DVDD = +5V, REF-A and REF-B = +5V, gain = 6,
AGND-x = DGND = 0V, data format = straight binary, and OFFSET-A = OFFSET-B = AGND, unless otherwise noted.
DAC7718
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
IOVDD – 0.4
IOVDD
V
1.6
IOVDD
V
DIGITAL OUTPUT (17)
High-level output voltage, VOH
(SDO)
IOVDD = +2.7V to +5.5V, sourcing 1mA
Low-level output voltage, VOL
(SDO)
IOVDD = +2.7V to +5.5V, sinking 1mA
0
0.4
V
IOVDD = +1.8V, sinking 200mA
0
0.2
V
GPIO-n output voltage low, VOL
1mA sink from IOVDD
IOVDD = +1.8V, sourcing 200mA
GPIO-n output voltage high, VOH 10kΩ pull-up resistor to IOVDD
V
±5
mA
5
pF
14
pF
0.99 × IOVDD
High-impedance leakage current SDO and GPIO-n
High-impedance output
capacitance
0.15
SDO
GPIO-n
V
POWER SUPPLY
AVDD
+9
+36
V
DVDD
+2.7
+5.5
V
IOVDD (18)
+1.8
+5.5
V
AIDD
DIDD
IOIDD
Power dissipation
Normal operation, midscale code, output unloaded
4.5
Power down, output unloaded
35
µA
Normal operation
70
mA
Power down
36
mA
Normal operation, VIH = IOVDD, VIL = DGND
5
mA
Power down, VIH = IOVDD, VIL = DGND
5
Normal operation
140
7
mA
mA
225
mW
+105
°C
TEMPERATURE RANGE
Specified performance
–40
(17) Specified by design.
(18) IOVDD ≤ DVDD.
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FUNCTIONAL BLOCK DIAGRAM
IOVDD
DGND
DVDD
AVDD
AVSS
REF-A
DAC7718
Analog Monitor
SCLK
CS
SDI
SDO
RST
RSTSEL
LDAC
CLR
USB/BTC
GPIO-0
GPIO-1
GPIO-2
Control Logic
Reference
Buffer A
OFFSET
DAC A
Command
Registers
To DAC-0, DAC-1,
DAC-2, DAC-3
(When Correction Engine Disabled)
Input Data
Register 0
Correction
Engine
DAC-0
Data
VMON
OFFSET-A
DAC-0
VOUT-0
Latch-0
To DAC-0, DAC-1,
DAC-2, DAC-3
LDAC
User Calibration:
Zero Register 0
Gain Regsiter 0
VOUT-7
AIN-0
AIN-1
Ref Buffer A
Ref Buffer B
OFFSET-B
Mux
WAKEUP
SPI Shift Register
VOUT-0
Internal Trimming
Zero/Gain; INL
AGND-A
To DAC-4, DAC-5, DAC-6, DAC-7
OFFSET-B
Reference
Buffer B
(Same Function Blocks
for All Channels)
OFFSET
DAC B
AIN-0
AGND-B
Power-Up/
Power-Down
Control
VOUT-7
AIN-1
DGND
DVDD
AVDD
AVSS
REF-B
Figure 1. Functional Block Diagram
10
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PIN CONFIGURATIONS
VOUT-3
REF-A
4
45
5
44
DGND
NC
RSTSEL
USB/BTC
39
38
37
IOVDD
41
40
SCLK
DVDD
AIN-1
42
46
CS
3
44
NC
AIN-0
43
AVDD
47
SDO
48
2
SDI
1
NC
45
AVDD
LDAC
49
46
50
WAKEUP
51
48
52
47
USB/BTC
53
NC
54
NC
55
RSTSEL
56
DGND
57
RGZ PACKAGE
QFN-48
(TOP VIEW)
NC
58
IOVDD
59
SCLK
60
DVDD
61
SDI
62
CS
63
SDO
LDAC
64
NC
NC
WAKEUP
PAG PACKAGE
TQFP-64
(TOP VIEW)
AVDD
1
36
AVDD
AIN-0
2
35
AIN-1
VOUT-3
3
34
VOUT-4
REF-A
4
33
REF-B
VOUT-4
REF-B
VOUT-2
6
43
VOUT-5
VOUT-1
7
42
VOUT-6
VOUT-2
5
32
VOUT-5
AGND-A
8
41
AGND-B
VOUT-1
6
31
VOUT-6
AGND-A
9
40
AGND-B
AGND-A
7
30
AGND-B
OFFSET-A 10
39
OFFSET-B
AGND-A
8
29
AGND-B
OFFSET-A
9
28
OFFSET-B
10
27
VOUT-7
DAC7718
VOUT-0 11
38
AVSS 12
37
DAC7718
VOUT-7
AVSS
(1)
20
21
22
23
24
NC
DGND
GPIO-1
GPIO-0
32
DGND
31
19
30
NC
29
17
28
18
27
NC
26
DVDD
25
16
24
NC
23
15
22
RST
21
13
20
14
19
CLR
18
GPIO-2
17
NC
NC
NC
33
GPIO-1
NC
NC 16
GPIO-0
25
DGND
12
NC
VMON
NC
NC
DVDD
34
DGND
AVSS
NC 15
NC
26
NC
11
RST
AVSS
CLR
NC
GPIO-2
NC
35
NC
36
VMON 14
NC
NC 13
VOUT-0
The thermal pad is internally connected to
the substrate. This pad can be connected
to AVSS or left floating. Keep the thermal
pad separate from the digital ground, if
possible.
PIN DESCRIPTIONS
(1)
PIN NO.
PIN
NAME
QFN-48
TQFP-64
I/O
AVDD
1
1
I
Positive analog power supply
DESCRIPTION
AIN-0
2
3
I
Auxiliary analog input 0, directly routed to the analog mux
VOUT-3
3
4
O
DAC-3 output
REF-A
4
5
I
Group A (1) reference input
VOUT-2
5
6
O
DAC-2 output
VOUT-1
6
7
O
DAC-1 output
AGND-A
7
8
I
Group A analog ground and the ground of REF-A. This pin must be tied to AGND-B and DGND.
AGND-A
8
9
I
Group A analog ground and the ground of REF-A. This pin must be tied to AGND-B and DGND.
OFFSET-A
9
10
O
OFFSET DAC-A analog output. Must be connected to AGND-A during single power-supply
operation (AVSS = 0V). This pin is not intended to drive an external load.
VOUT-0
10
11
O
DAC-0 output
AVSS
11
12
I
Negative analog power supply
VMON
12
14
O
Analog monitor output. This pin is either in Hi-Z status, connected to one of the eight DAC outputs,
reference buffer outputs, offset DAC outputs, or one of the auxiliary analog inputs, depending on
the content of the Monitor Register. See the Monitor Register, Table 12, for details.
GPIO-2
13
19
I/O
General-purpose digital input/output 2. This pin is a bidirectional digital input/output, open-drain and
requires an external pull-up resistor. See the GPIO Pins section for details.
CLR
14
20
I
Clear input, level triggered. When the CLR pin is logic '0', all VOUT-X pins connect to AGND-x
through switches and internal low-impedance. When the CLR pin is logic '1', all VOUT-X pins
connect to the amplifier outputs.
RST
15
21
I
Reset input (active low). Logic low on this pin resets the DAC registers and DACs to the values
defined by the RSTSEL pin. CS must be logic high when RST is active.
Group A consists of DAC-0, DAC-1, DAC-2, and DAC-3. Group B consists of DAC-4, DAC-5, DAC-6, and DAC-7.
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PIN DESCRIPTIONS (continued)
PIN
NAME
QFN-48
TQFP-64
I/O
DVDD
17
24
I
Digital power supply
DGND
20
25
I
Digital ground
DGND
22
28
I
Digital ground
GPIO-1
23
29
I/O
General-purpose digital input/output 1. This pin is a bidirectional digital input/output, open-drain and
requires an external resistor. See the GPIO Pins section for details.
GPIO-0
24
30
I/O
General-purpose digital input/output 0. This pin is a bidirectional digital input/output, open-drain and
requires an external resistor. See the GPIO Pins section for details.
DESCRIPTION
AVSS
26
37
I
Negative analog power supply
VOUT-7
27
38
O
DAC-7 output
OFFSET-B
28
39
O
OFFSET DAC-B analog output. Must be connected to AGND-B during single-supply operation
(AVSS = 0V).
AGND-B
29
40
I
Group B (1) analog ground and the ground of REF-B. This pin must be tied to AGND-A and DGND.
AGND-B
30
41
I
Group B analog ground and the ground of REF-B. This pin must be tied to AGND-A and DGND.
VOUT-6
31
42
O
DAC-6 output
VOUT-5
32
43
O
DAC-5 output
REF-B
33
44
I
Group B reference input
VOUT-4
34
45
O
DAC-4 output
AIN-1
35
46
I
Auxiliary analog input 1, directly routed to the analog mux
AVDD
36
48
I
Positive analog power supply
USB/BTC
37
50
I
Data format selection of Input DAC data and Offset DAC data. Data are in straight binary format
when connected to DGND or in twos complement format when connected to IOVDD. The command
data are always in straight binary format. Refer to Input Data Format section for details.
RSTSEL
38
51
I
Output reset selection. Selects the output voltage on the VOUT pin after power-on or hardware reset.
Refer to the Power-On Reset section for details.
DGND
40
54
I
Digital ground
IOVDD
41
55
I
Interface power
DVDD
42
56
I
Digital power supply
SCLK
43
57
I
SPI bus serial clock input
CS
44
58
I
SPI bus chip select input (active low). Data are not clocked into SDI unless CS is low. When CS is
high, SDO is in a high-impedance state and the SCLK and SDI signals are blocked from the device.
SDI
45
59
I
SPI bus serial data input
SDO
46
61
O
SPI bus serial data output.
When the DSDO bit = '0', the SDO pin works as an output in normal operation.
When the DSDO bit = '1', SDO is always in a Hi-Z state, regardless of the CS pin status. Refer to
the Timing Diagrams section for details.
LDAC
47
62
I
Load DAC latch control input (active low). When LDAC is low, the DAC latch is transparent and the
contents of the DAC Data Register are transferred to it. The DAC output changes to the
corresponding level simultaneously when the DAC latch is updated. See the Updating the DAC
Outputs section for details. If asynchronous mode is desired, LDAC must be permanently tied low
before power is applied to the device. If synchronous mode is desired, LDAC must be logic high
during power-on.
WAKEUP
48
63
I
Wake-up input (active low). Restores the SPI from sleep to normal operation. See the Daisy-Chain
Operation section for details.
16, 18, 19,
21, 25, 39
2, 13,
15-18, 22,
23, 26, 27,
31-36, 47,
49, 52, 53,
60, 64
—
NC
12
PIN NO.
Not connected
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TIMING DIAGRAMS
Case 1: Standalone mode: Update without LDAC pin; LDAC pin tied to logic low.
t8
t4
CS
t7
t1
Input Data Register and
DAC Latch Updated
When Correction Completes(1)
SCLK
t2
t3
t5
LDAC
t6
BIT 22
BIT 23 (MSB)
SDI
BIT 1
BIT 0
Low
NOTE: (1) If the correction engine is off, the DAC latch is reloaded immediately after the DAC Data Register is updated.
Case 2: Standalone mode: Update with LDAC pin.
t8
t4
CS
t7
t1
Input Data Register Updated,
but DAC Latch is Not Updated
SCLK
t2
t3
t5
BIT 23 (MSB)
SDI
LDAC
t6
BIT 22
BIT 1
BIT 0
t9
High
DAC Latch Updated
t10
(2)
NOTE: (2) The DAC latch is updated when LDAC goes low, as long as the timing requirement of t9 is satisfied.
= Don’t Care
Bit 23 = MSB
Bit 0 = LSB
Figure 2. SPI Timing for Standalone Mode
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TIMING DIAGRAMS (continued)
Case 3: Daisy-Chain Mode: Update without LDAC pin; LDAC pin tied to logic low.
t8
t4
Input Data Register and
DAC Latch Updated
When Correction Completes(1)
CS
t7
t1
SCLK
t2
t3
t5
BIT 23 (N)
SDI
t6
BIT 22 (N)
BIT 0 (N)
t13
LDAC
BIT 0 (N+1)
t12
t11
Hi-Z
SDO
BIT 23 (N+1)
BIT 23 (N)
Hi-Z
BIT 0 (N)
Low
NOTE: (1) If the correction engine is off, the DAC latch is reloaded immediately after the DAC Data Register is updated.
Case 4: Daisy-Chain Mode: Update with LDAC pin.
t8
t4
CS
Input Data Register Updated,
but DAC Latch is Not Updated
t7
t1
SCLK
t2
t3
t5
BIT 23 (N)
SDI
t6
BIT 22 (N)
BIT 0 (N)
t13
BIT 0 (N+1)
t12
t11
Hi-Z
BIT 23 (N)
SDO
LDAC
BIT 23 (N+1)
Hi-Z
BIT 0 (N)
t9
High
t10
DAC Latch Updated(2)
NOTE: (2) The DAC latch is updated when LDAC goes low. The proper data are loaded if the t9 timing requirement is satisfied.
Otherwise, invalid data are loaded.
Case 5: Daisy-Chain Mode: Sleeping.
CS
SCLK
First Word
DB23
SDI
Last Word
DB23
DB0
DB0
t14
Hi-Z
SDO
DB23
DB0
= Don’t Care
Hi-Z
DB23
DB0
Hi-Z
Bit 23 = MSB
Bit 0 = LSB
Figure 3. SPI Timing for Daisy-Chain Mode
14
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TIMING DIAGRAMS (continued)
Case 6: Readback for Standalone mode.
t8
t4
t7
CS
Internal Register Updated
t1
SCLK
t2
t3
t5
BIT 23 (= 1)
SDI
t6
BIT 22
BIT 0
BIT 23 (= 1)
t13
Input Word Specifies Register to be Read
SDO
LDAC
Hi-Z
Hi-Z
t11
BIT 23
BIT 22
BIT 1
BIT 0
NOP Command (write ‘1’ to NOP bit)
BIT 22
BIT 1
BIT 0
Hi-Z
Data from the Selected Register
Low
= Don’t Care
Bit 23 = MSB
Bit 0 = LSB
Figure 4. SPI Timing for Readback Operation in Standalone Mode
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TIMING CHARACTERISTICS: IOVDD = +5V (1) (2) (3) (4)
At –40°C to +105°C, DVDD = +5V, and IOVDD = +5V, unless otherwise noted.
PARAMETER
MIN
MAX
UNIT
50
MHz
fSCLK
Clock frequency
t1
SCLK cycle time
20
ns
t2
SCLK high time
10
ns
t3
SCLK low time
7
ns
t4
CS falling edge to SCLK falling edge setup time
8
ns
t5
SDI setup time before falling edge of SCLK
5
ns
t6
SDI hold time after falling edge of SCLK
5
ns
t7
SCLK falling edge to CS rising edge
5
ns
t8
CS high time
10
ns
t9
CS rising edge to LDAC falling edge
5
ns
t10
LDAC pulse duration
t11
Delay from SCLK rising edge to SDO valid
t12
Delay from CS rising edge to SDO Hi-Z
t13
Delay from CS falling edge to SDO valid
t14
SDI to SDO delay during sleep mode
(1)
(2)
(3)
(4)
10
3
2
ns
8
ns
5
ns
6
ns
5
ns
Specified by design. Not production tested.
Sample tested during the initial release and after any redesign or process changes that may affect these parameters.
All input signals are specified with tR = tF = 2ns (10% to 90% of IOVDD) and timed from a voltage level of IOVDD/2.
SDO loaded with 10Ω series resistance and 10pF load capacitance for SDO timing specifications.
BLANKSPACE
TIMING CHARACTERISTICS: IOVDD = +3V (1) (2) (3) (4)
At –40°C to +105°C, DVDD = +3V/+5V, and IOVDD = +3V, unless otherwise noted.
PARAMETER
MIN
MAX
UNIT
25
MHz
fSCLK
Clock frequency
t1
SCLK cycle time
40
ns
t2
SCLK high time
19
ns
t3
SCLK low time
7
ns
t4
CS falling edge to SCLK falling edge setup time
15
ns
t5
SDI setup time before falling edge of SCLK
5
ns
t6
SDI hold time after falling edge of SCLK
5
ns
t7
SCLK falling edge to CS rising edge
10
ns
t8
CS high time
19
ns
t9
CS rising edge to LDAC falling edge
5
ns
t10
LDAC pulse duration
t11
Delay from SCLK rising edge to SDO valid
t12
t13
t14
SDI to SDO delay during sleep mode
(1)
(2)
(3)
(4)
16
10
3
ns
15
ns
Delay from CS rising edge to SDO Hi-Z
7
ns
Delay from CS falling edge to SDO valid
10
ns
10
ns
2
Specified by design. Not production tested.
Sample tested during the initial release and after any redesign or process changes that may affect these parameters.
All input signals are specified with tR = tF = 3ns (10% to 90% of IOVDD) and timed from a voltage level of IOVDD/2.
SDO loaded with 10Ω series resistance and 10pF load capacitance for SDO timing specifications.
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TIMING CHARACTERISTICS: IOVDD = +1.8V (1) (2) (3) (4)
At –40°C to +105°C, DVDD = +3V/+5V, and IOVDD = +1.8V, unless otherwise noted.
PARAMETER
MIN
MAX
UNIT
16.6
MHz
fSCLK
Clock frequency
t1
SCLK cycle time
60
ns
t2
SCLK high time
28
ns
t3
SCLK low time
7
ns
t4
CS falling edge to SCLK falling edge setup time
28
ns
t5
SDI setup time before falling edge of SCLK
10
ns
t6
SDI hold time after falling edge of SCLK
5
ns
t7
SCLK falling edge to CS rising edge
10
ns
t8
CS high time
28
ns
t9
CS rising edge to LDAC falling edge
5
ns
t10
LDAC pulse duration
t11
Delay from SCLK rising edge to SDO valid
t12
Delay from CS rising edge to SDO Hi-Z
t13
Delay from CS falling edge to SDO valid
t14
SDI to SDO delay during sleep mode
(1)
(2)
(3)
(4)
10
3
2
ns
25
ns
15
ns
23
ns
25
ns
Specified by design. Not production tested.
Sample tested during the initial release and after any redesign or process changes that may affect these parameters.
All input signals are specified with tR = tF = 6ns (10% to 90% of IOVDD) and timed from a voltage level of IOVDD/2.
SDO loaded with 10Ω series resistance and 10pF load capacitance for SDO timing specifications.
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TYPICAL CHARACTERISTICS: Bipolar
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 Channels)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 Channels)
1.0
1.0
All Eight Channels Shown
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
All Eight Channels Shown
0.8
0.2
0
-0.2
-0.4
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
1024
1536 2048 2560
Digital Input Code
3072
Figure 6.
LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
3584
4096
1.0
Typical Channel Shown
Gain = 4
0.8
0.4
DNL Error (LSB)
0.6
0.4
0.2
0
-0.2
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
Typical Channel Shown
Gain = 4
0.8
0.6
-0.4
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
Figure 7.
18
512
Figure 5.
1.0
INL Error (LSB)
0.2
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
Figure 8.
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DAC7718
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs DIGITAL INPUT CODE (–40°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (–40°C)
1.0
1.0
Typical Channel Shown
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
Typical Channel Shown
0.8
0.2
0
-0.2
-0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
512
1024
1536 2048 2560
Digital Input Code
Figure 9.
Figure 10.
LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
1.0
4096
Typical Channel Shown
0.8
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
3584
1.0
Typical Channel Shown
0.2
0
-0.2
-0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
512
1024
1536 2048 2560
Digital Input Code
3072
Figure 11.
Figure 12.
LINEARITY ERROR
vs DIGITAL INPUT CODE (+105°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+105°C)
1.0
3584
4096
1.0
Typical Channel Shown
Typical Channel Shown
0.8
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
3072
0.2
0
-0.2
-0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
Figure 13.
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
Figure 14.
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
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TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs TEMPERATURE
DIFFERENTIAL LINEARITY ERROR
vs TEMPERATURE
1.0
1.0
0.8
0.8
0.6
0.4
INL Max
DNL Error (LSB)
INL Error (LSB)
0.6
0.2
0
-0.2
INL Min
-0.4
-0.2
-0.8
20 35 50 65
Temperature (°C)
80
DNL Min
-0.4
-0.8
5
DNL Max
0
-0.6
-55 -40 -25 -10
-1.0
95 110 125
-55 -40 -25 -10
20 35 50 65
Temperature (°C)
80
Figure 16.
LINEARITY ERROR
vs TEMPERATURE
DIFFERENTIAL LINEARITY ERROR
vs TEMPERATURE
95 110 125
1.0
Gain = 4
0.8
Gain = 4
0.8
0.6
0.6
0.4
DNL Error (LSB)
INL Max
0.2
0
-0.2
INL Min
-0.4
0.4
0.2
-0.2
-0.6
-0.8
5
20 35 50 65
Temperature (°C)
80
DNL Min
-0.4
-0.8
-55 -40 -25 -10
DNL Max
0
-0.6
-1.0
-1.0
95 110 125
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
Figure 17.
Figure 18.
LINEARITY ERROR
vs REFERENCE VOLTAGE
DIFFERENTIAL LINEARITY ERROR
vs REFERENCE VOLTAGE
1.0
95 110 125
1.0
AVDD = +18V
AVSS = -18V
0.8
AVDD = +18V
AVSS = -18V
0.8
0.6
0.6
0.4
DNL Error (LSB)
INL Max
0.2
0
-0.2
-0.4
INL Min
0.4
0.2
DNL Max
0
-0.2
DNL Min
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
1.0
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
1.0
Figure 19.
20
5
Figure 15.
1.0
INL Error (LSB)
0.2
-0.6
-1.0
INL Error (LSB)
0.4
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
Figure 20.
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DAC7718
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs AVDD AND AVSS
DIFFERENTIAL LINEARITY ERROR
vs AVDD AND AVSS
1.0
1.0
DVDD = IOVDD = 4.5V
VREF = 2.048V
Gain = 4
0.8
0.4
INL Max
0.2
0
-0.2
INL Min
-0.4
0.6
DNL Error (LSB)
INL Error (LSB)
0.6
0.2
DNL Max
0
DNL Min
-0.2
-0.4
-0.6
-0.8
-0.8
-1.0
6.0
7.5
9.0 10.5 12.0 13.5
AVDD = -AVSS (V)
15.0
16.5
18.0
4.5
6.0
7.5
9.0 10.5 12.0 13.5
AVDD = -AVSS (V)
Figure 21.
Figure 22.
BIPOLAR ZERO ERROR
vs AVDD AND AVSS
BIPOLAR GAIN ERROR
vs AVDD AND AVSS
5
DVDD = IOVDD = 4.5V
VREF = 2.048V
Gain = 4
4
3
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
Ch4
Ch5
Ch6
Ch7
5
3
16.5
18.0
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
-5
15.0
DVDD = IOVDD = 4.5V
VREF = 2.048V
Gain = 4
4
Bipolar Gain Error (mV)
4.5
Bipolar Zero Error (mV)
0.4
-0.6
-1.0
Ch4
Ch5
Ch6
Ch7
-5
4.5
6.0
7.5
9.0 10.5 12.0 13.5
AVDD = -AVSS (V)
15.0
16.5
18.0
4.5
6.0
7.5
9.0 10.5 12.0 13.5
AVDD = -AVSS (V)
Figure 23.
Figure 24.
BIPOLAR ZERO ERROR
vs REFERENCE VOLTAGE
BIPOLAR ZERO ERROR
vs REFERENCE VOLTAGE
5
15.0
16.5
18.0
5
AVDD = +18V
AVSS = -18V
4
3
2
1
0
-1
-2
Ch4
Ch5
Ch6
Ch7
Ch0
Ch1
Ch2
Ch3
-3
-4
AVDD = +18V
AVSS = -18V
Gain = 4
4
Bipolar Zero Error (mV)
Bipolar Zero Error (mV)
DVDD = IOVDD = 4.5V
VREF = 2.048V
Gain = 4
0.8
3
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
-5
Ch4
Ch5
Ch6
Ch7
-5
1.0
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
1.0
Figure 25.
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
Figure 26.
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DAC7718
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
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TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
BIPOLAR GAIN ERROR
vs REFERENCE VOLTAGE
BIPOLAR GAIN ERROR
vs REFERENCE VOLTAGE
5
5
AVDD = +18V
AVSS = -18V
3
2
1
0
-1
-2
Ch4
Ch5
Ch6
Ch7
Ch0
Ch1
Ch2
Ch3
-3
-4
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-4
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
1.0
5.5
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
Figure 27.
Figure 28.
BIPOLAR ZERO ERROR
vs TEMPERATURE
BIPOLAR ZERO ERROR
vs TEMPERATURE
5
4
4
3
3
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-5
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
Ch4
Ch5
Ch6
Ch7
Bipolar Zero Error (mV)
5
-4
5.0
5.5
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-5
95 110 125
4.5
Gain = 4
-4
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
Figure 29.
Figure 30.
BIPOLAR GAIN ERROR
vs TEMPERATURE
BIPOLAR GAIN ERROR
vs TEMPERATURE
5
80
Ch4
Ch5
Ch6
Ch7
95 110 125
5
3
2
Ch4
Ch5
Ch6
Ch7
1
0
-1
-2
-3
-4
Gain = 4
4
Bipolar Gain Error (mV)
Ch0
Ch1
Ch2
Ch3
4
3
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
-5
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
95 110 125
-5
-55 -40 -25 -10
Figure 31.
22
Ch4
Ch5
Ch6
Ch7
-5
1.0
Bipolar Zero Error (mV)
3
-3
-5
Bipolar Gain Error (mV)
AVDD = +18V
AVSS = -18V
Gain = 4
4
Bipolar Gain Error (mV)
Bipolar Gain Error (mV)
4
5
20 35 50 65
Temperature (°C)
80
Ch4
Ch5
Ch6
Ch7
95 110 125
Figure 32.
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
ANALOG POWER-SUPPLY CURRENT
vs TEMPERATURE
ANALOG POWER-SUPPLY CURRENT
vs REFERENCE VOLTAGE
8
Analog Power-Supply Current (mA)
Analog Power-Supply Current (mA)
8
7
6
IAVDD
5
4
-IAVSS
3
2
1
0
5
20 35 50 65
Temperature (°C)
80
95 110 125
5
IAVDD
4
3
2
-IAVSS
1
1.0
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
Figure 33.
Figure 34.
ANALOG POWER-SUPPLY CURRENT
vs DIGITAL INPUT CODE
DIGITAL POWER-SUPPLY CURRENT
vs LOGIC INPUT VOLTAGE
8
250
All DACs Loaded with Same Code
Digital Power-Supply Current (mA)
Analog Power-Supply Current (mA)
6
0
-55 -40 -25 -10
6
4
IAVDD
2
0
IAVSS
-2
-4
-6
5.5
One Digital Input Swept, All Others at GND or IOVDD
200
Sweep From
0V to 5.5V
Sweep From
5.5V to 0V
150
100
50
0
-8
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
0.5
1.0
1.5
2.0 2.5 3.0 3.5 4.0
Logic Input Voltage (V)
Figure 35.
Figure 36.
DELTA OUTPUT VOLTAGE
vs SOURCE AND SINK CURRENTS
DAC OUTPUT NOISE DENSITY
vs FREQUENCY
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
2000
FFFh
C00h
800h
400h
000h
4.5
5.0
5.5
DAC Loaded with Midscale Code
1800
1600
Noise (nV/ÖHz)
DVOUT (mV)
All DACs Loaded with Midscale Code
AVDD = +18V
AVSS = -18V
7
1400
1200
1000
800
600
Gain = 6
400
Gain = 4
200
0
-15 -12
-9
-6
-3
0
3
6
Current Output IOUT (mA)
9
12
15
1
Figure 37.
10
100
1k
Frequency (Hz)
10k
100k
Figure 38.
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DAC7718
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
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TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
SETTLING TIME
–15V TO +15V TRANSITION
SETTLING TIME
+15V TO –15V TRANSITION
Large-Signal VOUT
5V/div
From Code: FFFh
To Code: 000h
Load: 10kW || 240pF
5V/div
Small-Signal Error
Small-Signal Error
1 LSB/div
5V/div
Trigger Pulse: LDAC
From Code: 000h
To Code: FFFh
Load: 10kW || 240pF
1 LSB/div
Large-Signal VOUT
5V/div
Trigger Pulse: LDAC
Time (10ms/div)
Time (10ms/div)
Figure 39.
Figure 40.
SETTLING TIME
1/4 TO 3/4 FULL-SCALE TRANSITION
SETTLING TIME
3/4 TO 1/4 FULL-SCALE TRANSITION
Large-Signal VOUT
5V/div
Small-Signal Error
Small-Signal Error
1 LSB/div
1 LSB/div
Large-Signal VOUT
5V/div
5V/div
Trigger Pulse: LDAC
From Code: 400h
To Code: C00h
Load: 10kW || 240pF
5V/div
Trigger Pulse: LDAC
From Code: C00h
To Code: 400h
Load: 10kW || 240pF
Time (10ms/div)
Time (10ms/div)
Figure 41.
Figure 42.
GLITCH ENERGY
1 LSB STEP, RISING EDGE
GLITCH ENERGY
1 LSB STEP, FALLING EDGE
Glitch Impulse
Trigger Pulse 5V/div
From Code: 7FFh
To Code: 800h
Channel 0 as Example
Load: 10kW || 200pF
VOUT (3mV/div)
VOUT (3mV/div)
From Code: 800h
To Code: 7FFh
Channel 0 as Example
Load: 10kW || 200pF
Time (2ms/div)
Trigger Pulse 5V/div
Time (2ms/div)
Figure 43.
24
Glitch Impulse
Figure 44.
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
BIPOLAR ZERO ERROR
HISTOGRAM
60
55
55
50
50
45
45
40
40
25
Bipolar Zero Error (LSB)
1.0
0.8
0.6
0.2
-1.0
1.0
0.8
0.6
0.4
0.2
-0.8
0
0
-0.2
5
0
-0.4
10
5
-0.6
15
10
0.4
20
15
0
20
30
-0.2
25
35
-0.4
30
-0.8
35
Gain = 4
-0.6
Population (%)
60
-1.0
Population (%)
BIPOLAR ZERO ERROR
HISTOGRAM
Bipolar Zero Error (LSB)
Figure 45.
Figure 46.
BIPOLAR GAIN ERROR
HISTOGRAM
BIPOLAR GAIN ERROR
HISTOGRAM
40
40
35
35
30
30
20
Bipolar Gain Error (LSB)
1.0
0.8
0.6
0.4
0.2
0
1.0
0.6
0.2
-0.4
-0.8
-1.0
0
0.8
0
0.4
5
0
5
-0.2
10
-0.6
10
-0.2
15
-0.4
15
25
-0.8
20
-0.6
Population (%)
25
-1.0
Population (%)
Gain = 4
Bipolar Gain Error (LSB)
Figure 47.
Figure 48.
NEGATIVE ANALOG POWER SUPPLY
HISTOGRAM
POSITIVE ANALOG POWER SUPPLY
HISTOGRAM
55
45
50
40
45
35
Population (%)
Population (%)
40
35
30
25
20
30
25
20
15
15
AISS (mA)
Figure 49.
6.0
5.6
5.8
5.4
5.0
5.2
4.8
4.4
4.6
4.0
4.2
3.8
3.6
3.2
3.4
2.8
-1.0
-1.2
-1.6
-1.4
-1.8
-2.2
-2.0
-2.4
-2.8
-2.6
-3.0
-3.4
-3.2
-3.6
0
-4.0
5
0
-3.8
5
3.0
10
10
AIDD (mA)
Figure 50.
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DAC7718
SBAS361A – MAY 2009 – REVISED DECEMBER 2009
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TYPICAL CHARACTERISTICS: Bipolar (continued)
At TA = 25°C, AVDD = 16.5V, AVSS = –16.5V, VREF = IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
VOUT (5mV/div)
DAC OUTPUT NOISE
0.1Hz TO 10Hz
VOUT (5mV/div)
DAC OUTPUT NOISE
0.1Hz TO 10Hz
DAC Code = 800h
No Load
Gain = 6
Channel 0 as Example
Time (2ms/div)
Time (2ms/div)
Figure 51.
26
DAC Code = 800h
No Load
Gain = 4
Channel 0 as Example
Figure 52.
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
TYPICAL CHARACTERISTICS: Unipolar
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 Channels)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 Channels)
1.0
1.0
All Eight Channels Shown
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
All Eight Channels Shown
0.8
0.2
0
-0.2
-0.4
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
512
1024
1536 2048 2560
Digital Input Code
3072
Figure 53.
Figure 54.
LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
1.0
3584
4096
1.0
Typical Channel Shown
Gain = 4
0.8
0.6
0.6
0.4
0.4
0.2
0
-0.2
-0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
Typical Channel Shown
Gain = 4
0.8
DNL Error (LSB)
INL Error (LSB)
0.2
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
Figure 55.
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
Figure 56.
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TYPICAL CHARACTERISTICS: Unipolar (continued)
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs DIGITAL INPUT CODE (–40°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (–40°C)
1.0
1.0
Typical Channel Shown
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
Typical Channel Shown
0.8
0.2
0
-0.2
-0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
512
1024
1536 2048 2560
Digital Input Code
Figure 57.
Figure 58.
LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
1.0
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
4096
Typical Channel Shown
0.8
0.2
0
-0.2
-0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
512
1024
1536 2048 2560
Digital Input Code
3072
Figure 59.
Figure 60.
LINEARITY ERROR
vs DIGITAL INPUT CODE (+105°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+105°C)
1.0
3584
4096
1.0
Typical Channel Shown
Typical Channel Shown
0.8
0.8
0.6
0.6
0.4
0.4
DNL Error (LSB)
INL Error (LSB)
3584
1.0
Typical Channel Shown
0.2
0
-0.2
-0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
0
Figure 61.
28
3072
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
Figure 62.
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TYPICAL CHARACTERISTICS: Unipolar (continued)
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs TEMPERATURE
DIFFERENTIAL LINEARITY ERROR
vs TEMPERATURE
1.0
1.0
Gain = 4
0.8
0.8
0.6
0.4
INL Max
DNL Error (LSB)
INL Error (LSB)
0.6
0.2
0
-0.2
INL Min
-0.4
DNL Max
0
-0.2
DNL Min
-0.4
-0.6
-0.8
-0.8
-1.0
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
95 110 125
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
Figure 63.
Figure 64.
LINEARITY ERROR
vs TEMPERATURE
DIFFERENTIAL LINEARITY ERROR
vs TEMPERATURE
1.0
95 110 125
1.0
Gain = 4
0.8
Gain = 4
0.8
0.6
0.6
0.4
INL Max
DNL Error (LSB)
INL Error (LSB)
0.2
-0.6
-1.0
0.2
0
-0.2
INL Min
-0.4
0.4
0.2
DNL Max
0
-0.2
DNL Min
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
-1.0
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
95 110 125
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
Figure 65.
Figure 66.
LINEARITY ERROR
vs REFERENCE VOLTAGE
DIFFERENTIAL LINEARITY ERROR
vs REFERENCE VOLTAGE
1.0
95 110 125
1.0
AVDD = +36V
0.8
AVDD = +36V
0.8
0.6
0.6
0.4
INL Max
DNL Error (LSB)
INL Error (LSB)
0.4
0.2
0
-0.2
-0.4
INL Min
0.4
0.2
-0.2
DNL Min
-0.4
-0.6
-0.6
-0.8
-0.8
-1.0
DNL Max
0
-1.0
1.0
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
1.0
Figure 67.
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
Figure 68.
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TYPICAL CHARACTERISTICS: Unipolar (continued)
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
LINEARITY ERROR
vs ANALOG SUPPLY VOLTAGE
DIFFERENTIAL LINEARITY ERROR
vs ANALOG SUPPLY VOLTAGE
1.0
1.0
DVDD = IOVDD = 4.5V
VREF = 2.048V
Gain = 4
0.8
0.4
INL Max
0.2
0
-0.2
INL Min
-0.4
0.6
DNL Error (LSB)
INL Error (LSB)
0.6
0.2
DNL Max
0
-0.2
DNL Min
-0.4
-0.6
-0.8
-0.8
-1.0
9
12
15
18
21
24
AVDD (V)
27
30
33
36
9
15
18
21
24
AVDD (V)
27
30
Figure 70.
ZERO-SCALE ERROR
vs ANALOG SUPPLY VOLTAGE
UNIPOLAR GAIN ERROR
vs ANALOG SUPPLY VOLTAGE
33
36
5
3
2
1
0
-1
-2
Ch4
Ch5
Ch6
Ch7
Ch0
Ch1
Ch2
Ch3
-3
-4
DVDD = IOVDD = 4.5V
VREF = 2.048V
Gain = 4
4
Unipolar Gain Error (mV)
DVDD = IOVDD = 4.5V
VREF = 2.048V
Code = 010h
Gain = 4
4
3
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
-5
Ch4
Ch5
Ch6
Ch7
-5
9
12
15
18
21
24
AVDD (V)
27
30
33
36
9
12
15
18
21
24
AVDD (V)
27
30
Figure 71.
Figure 72.
ZERO-SCALE ERROR
vs REFERENCE VOLTAGE
ZERO-SCALE ERROR
vs REFERENCE VOLTAGE
5
33
36
5
AVDD = +36V
Code = 010h
4
AVDD = +36V
Code = 010h
Gain = 4
4
3
Zero-Scale Error (mV)
3
2
1
0
-1
-2
Ch4
Ch5
Ch6
Ch7
Ch0
Ch1
Ch2
Ch3
-3
-4
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
-5
Ch4
Ch5
Ch6
Ch7
-5
1.0
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
1.0
Figure 73.
30
12
Figure 69.
5
Zero-Scale Error (mV)
0.4
-0.6
-1.0
Zero-Scale Error (mV)
DVDD = IOVDD = 4.5V
VREF = 2.048V
Gain = 4
0.8
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
Figure 74.
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TYPICAL CHARACTERISTICS: Unipolar (continued)
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
UNIPOLAR GAIN ERROR
vs REFERENCE VOLTAGE
UNIPOLAR GAIN ERROR
vs REFERENCE VOLTAGE
5
5
AVDD = +36V
3
2
1
0
-1
-2
Ch4
Ch5
Ch6
Ch7
Ch0
Ch1
Ch2
Ch3
-3
-4
2
1
0
-1
-2
Ch4
Ch5
Ch6
Ch7
Ch0
Ch1
Ch2
Ch3
-3
-5
1.0
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
4.5
5.0
1.0
5.5
1.5
2.0
2.5
3.0
3.5
VREF (V)
4.0
Figure 75.
Figure 76.
ZERO-SCALE ERROR
vs TEMPERATURE
ZERO-SCALE ERROR
vs TEMPERATURE
5
4.5
5.0
5.5
5
Code = 010h
4
Code = 010h
Gain = 4
4
3
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
Ch4
Ch5
Ch6
Ch7
Zero-Scale Error (mV)
3
Zero-Scale Error (mV)
3
-4
-5
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
-5
Ch4
Ch5
Ch6
Ch7
-5
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
95 110 125
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
Figure 77.
Figure 78.
UNIPOLAR GAIN ERROR
vs TEMPERATURE
UNIPOLAR GAIN ERROR
vs TEMPERATURE
5
95 110 125
5
3
2
Ch4
Ch5
Ch6
Ch7
1
0
-1
-2
-3
-4
Gain = 4
4
Unipolar Gain Error (mV)
Ch0
Ch1
Ch2
Ch3
4
Unipolar Gain Error (mV)
AVDD = +36V
Gain = 4
4
Unipolar Gain Error (mV)
Unipolar Gain Error (mV)
4
3
2
1
0
-1
-2
Ch0
Ch1
Ch2
Ch3
-3
-4
-5
Ch4
Ch5
Ch6
Ch7
-5
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
95 110 125
-55 -40 -25 -10
Figure 79.
5
20 35 50 65
Temperature (°C)
80
95 110 125
Figure 80.
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TYPICAL CHARACTERISTICS: Unipolar (continued)
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
ANALOG POWER-SUPPLY CURRENT
vs TEMPERATURE
ANALOG POWER-SUPPLY CURRENT
vs REFERENCE VOLTAGE
8
Analog Power-Supply Current (mA)
Analog Power-Supply Current (mA)
8
7
6
5
4
3
2
1
0
All DACs Loaded with Midscale Code
AVDD = +36V
7
6
5
IAVDD
4
3
2
1
0
-55 -40 -25 -10
5
20 35 50 65
Temperature (°C)
80
95 110 125
1.0
1.5
2.0
2.5
Figure 81.
3.0
3.5
VREF (V)
4.0
4.5
5.0
5.5
Figure 82.
ANALOG POWER-SUPPLY CURRENT
vs DIGITAL INPUT CODE
Analog Power-Supply Current (mA)
8
All DACs Loaded with Same Code
7
6
IAVDD
5
4
3
2
1
0
0
512
1024
1536 2048 2560
Digital Input Code
3072
3584
4096
Figure 83.
OUTPUT VOLTAGE
vs SOURCE CURRENT CAPABILITY
OUTPUT VOLTAGE
vs SINK CURRENT CAPABILITY
30.5
2.5
Output Voltage VOUT (V)
30.0
29.5
Output Voltage VOUT (V)
FFFh
FF0h
FE0h
FC0h
F80h
29.0
28.5
28.0
000h
010h
020h
040h
080h
2.0
1.5
1.0
0.5
27.5
0
3
6
9
12
15
0 -15
ISOURCE (mA)
-9
-6
-3
0
ISINK (mA)
Figure 84.
32
-12
Figure 85.
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TYPICAL CHARACTERISTICS: Unipolar (continued)
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
SETTLING TIME
0V TO 30V TRANSITION
SETTLING TIME
30V TO 0V TRANSITION
Large-Signal VOUT
5V/div
From Code: FFFh
To Code: 010h
Load: 10kW || 240pF
5V/div
Small-Signal Error
Small-Signal Error
1 LSB/div
1 LSB/div
5V/div
Trigger Pulse: LDAC
From Code: 010h
To Code: FFFh
Load: 10kW || 240pF
Large-Signal VOUT
5V/div
Trigger Pulse: LDAC
Time (10ms/div)
Time (10ms/div)
Figure 86.
Figure 87.
SETTLING TIME
1/4 TO 3/4 TRANSITION
SETTLING TIME
3/4 TO 1/4 TRANSITION
Large-Signal VOUT
5V/div
Small-Signal Error
Small-Signal Error
1 LSB/div
1 LSB/div
Large-Signal VOUT
5V/div
5V/div
Trigger Pulse: LDAC
From Code: 400h
To Code: C00h
Load: 10kW || 240pF
5V/div
Trigger Pulse: LDAC
From Code: C00h
To Code: 400h
Load: 10kW || 240pF
Time (10ms/div)
Time (10ms/div)
Figure 88.
Figure 89.
GLITCH ENERGY
1 LSB STEP, RISING EDGE
GLITCH ENERGY
1 LSB STEP, FALLING EDGE
Glitch Impulse
Trigger Pulse 5V/div
From Code: 7FFh
To Code: 800h
Channel 0 as Example
Load: 10kW || 200pF
VOUT (3mV/div)
VOUT (3mV/div)
From Code: 800h
To Code: 7FFh
Channel 0 as Example
Load: 10kW || 200pF
Time (2ms/div)
Glitch Impulse
Trigger Pulse 5V/div
Time (2ms/div)
Figure 90.
Figure 91.
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TYPICAL CHARACTERISTICS: Unipolar (continued)
At TA = 25°C, AVDD = 32V, AVSS = 0V, VREF = 5V, IOVDD = DVDD = 5V, gain = 6, data format=USB, unless otherwise noted.
ZERO-SCALE ERROR
HISTOGRAM
ZERO-SCALE ERROR
HISTOGRAM
-1.0
1.0
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
0
Zero-Scale Error (LSB)
1.0
5
0.8
10
0.6
15
0.4
20
0.2
25
0
30
-0.2
35
Population (%)
Population (%)
40
Code = 010h
Gain = 4
-0.4
45
60
55
50
45
40
35
30
25
20
15
10
5
0
-0.6
Code = 010h
-0.8
50
Zero-Scale Error (LSB)
Figure 92.
Figure 93.
UNIPOLAR GAIN ERROR
HISTOGRAM
UNIPOLAR GAIN ERROR
HISTOGRAM
35
40
30
35
Gain = 4
30
Population (%)
20
15
10
25
20
15
Unipolar Gain Error (LSB)
1.0
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-1.0
1.0
0.8
0.6
0.4
0.2
0
-0.2
-0.4
0
-0.6
0
-0.8
5
-1.0
5
-0.6
10
-0.8
Population (%)
25
Unipolar Gain Error (LSB)
Figure 94.
Figure 95.
ANALOG POWER-SUPPLY CURRENT
HISTOGRAM
45
40
Population (%)
35
30
25
20
15
10
5
7.0
6.6
6.2
5.8
5.4
5.0
4.6
4.2
3.8
3.4
3.0
2.6
0
AIDD (mA)
Figure 96.
34
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SBAS361A – MAY 2009 – REVISED DECEMBER 2009
THEORY OF OPERATION
GENERAL DESCRIPTION
The DAC7718 contains eight DAC channels and eight output amplifiers in a single package. Each channel
consists of a resistor-string DAC followed by an output buffer amplifier. The resistor-string section is simply a
string of resistors, each with a value of R, from REF-x to AGND, as shown in Figure 97. This type of architecture
provides DAC monotonicity. The 12-bit binary digital code loaded to the DAC latch determines at which node on
the string the voltage is tapped off before being fed into the output amplifier. The output amplifier multiplies the
DAC output voltage by a gain of six or four. Using a gain of 6 and power supplies allowing for at least 0.5V
headroom, the output span is 9V with a 1.5V reference, 18V with a 3V reference, and 30V with a 5V reference.
REF-x
R
R
R
To Output
Amplifier
R
R
Figure 97. Resistor String
CHANNEL GROUPS
The eight DAC channels and two Offset DACs are arranged into two groups (A and B) with four channels and
one Offset DAC per group. Group A consists of DAC-0, DAC-1, DAC-2, DAC-3, and Offset DAC-A. Group B
consists of DAC-4, DAC-5, DAC-6, DAC-7, and Offset DAC-B. Group A derives its reference voltage from
REF-A, and Group B derives its reference voltage from REF-B.
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USER-CALIBRATION FOR ZERO-CODE ERROR AND GAIN ERROR
The DAC7718 implements a digital user-calibration function that allows for trimming gain and zero errors on the
entire signal chain. This function can eliminate the need for external adjustment circuits. Each DAC channel has
a Zero Register and Gain Register. Using the correction engine, the data from the Input Data Register are
operated on by a digital adder and multiplier controlled by the contents of the Zero and Gain registers,
respectively. The calibrated DAC data are then stored in the DAC Data Register where they are finally
transferred into the DAC latch and set the DAC output. Each time the data are written to the Input Data Register
(or to the Gain or Zero registers), the data in the Input Data Register are corrected, and the results automatically
transferred to the DAC Data Register.
The range of the gain adjustment coefficient is 0.5 to 1.5. The range of the zero adjustment is –2048 LSB to
+2047 LSB, or ±50% of full scale.
There is only one correction engine in the DAC7718, which is shared among all channels.
If the user-calibration function is not needed, the correction engine can be turned off. Setting the SCE bit in the
Configuration Register to '0' turns off the correction engine. Setting SCE to '1' enables the correction engine.
When SCE = '0', the data are directly transferred to the DAC Data Register. In this case, writing to the Gain
Register or Zero Register updates the Gain and Zero registers but does not start a math engine calculation.
Reading these registers returns the written values.
36
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ANALOG OUTPUTS (VOUT-0 to VOUT-7, with reference to the ground of REF-x)
When the correction engine is off (SCE = '0'):
VOUT = VREF ´ Gain ´
INPUT_CODE
OFFSETDAC_CODE
- VREF ´ (Gain - 1) ´
4096
4096
(1)
SPACE
When the correction engine is on (SCE = '1'):
VOUT = VREF ´ Gain ´
DAC_DATA_CODE
OFFSETDAC_CODE
- VREF ´ (Gain - 1) ´
4096
4096
(2)
SPACE
Where:
DAC_DATA_CODE =
INPUT_CODE ´ (USER_GAIN + 211)
212
+ USER_ZERO
Gain = the DAC gain defined by the GAIN bit in the Configuration Register.
INPUT_CODE = data written into the Input Data Register (SCE = '1') or DAC Data Register (SCE = '0').
OFFSETDAC_CODE = the data written into the Offset DAC Register.
USER_GAIN = the code of the Gain Register.
USER_ZERO = the code of the Zero Register.
For single-supply operation, the OFFSET-A pin must be connected to the AGND-A pin and the OFFSET-B pin
must be connected to the AGND-B pin through low-impedance connections (see the Layout section for details).
Offset DAC-A and Offset DAC-B are in a power-down state.
For dual-supply operation, the OFFSET-A and OFFSET-B default codes for a gain of 6 are 2458 with a ±1 LSB
variation, depending on the linearity of the Offset DACs. The default code for a gain of 4 is 2731 with a ±1 LSB
variation. The default codes of OFFSET-A and OFFSET-B are independently factory trimmed for both gains of 6
and 4.
The power-on default value of the Gain Register is 2048, and the default value of the Zero Register is '0'. The
DAC input registers are set to a default value of 000h.
Note that the maximum output voltage must not be greater than (AVDD – 0.5V) and the minimum output voltage
must not be less than (AVSS + 0.5V); otherwise, the output may be saturated.
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INPUT DATA FORMAT
The USB/BTC pin defines the input data format and the Offset DAC format. When this pin is connected to
DGND, the Input DAC data and Offset DAC data are straight binary, as shown in Table 1 and Table 3. When this
pin is connected to IOVDD, the Input DAC data and Offset DAC data are in twos complement format, as shown in
Table 2 and Table 4.
Table 1. Bipolar Output vs Straight Binary Code Using Dual Power Supplies with Gain = 6
USB CODE
NOMINAL OUTPUT
DESCRIPTION
FFFh
+3 × VREF × (2047/2048)
+Full-Scale – 1 LSB
••• •••
••• •••
••• •••
801h
+3 × VREF × (1/2048)
+1 LSB
800h
0
Zero
7FFh
–3 × VREF × (1/2048)
–1 LSB
••• •••
••• •••
••• •••
000h
–3 × VREF × (2048/2048)
–Full-Scale
Table 2. Bipolar Output vs Twos Complement Code Using Dual Power Supplies with Gain = 6
BTC CODE
NOMINAL OUTPUT
DESCRIPTION
7FFh
+3 × VREF × (2047/2048)
+Full-Scale – 1 LSB
••• •••
••• •••
••• •••
001h
+3 × VREF × (1/2048)
+1 LSB
000h
0
Zero
FFFh
–3 × VREF × (1/2048)
–1 LSB
••• •••
••• •••
••• •••
800h
–3 × VREF × (2048/2048)
–Full-Scale
Table 3. Unipolar Output vs Straight Binary Code Using Single Power Supply with Gain = 6
USB CODE
NOMINAL OUTPUT
DESCRIPTION
FFFh
+6 × VREF × (4095/4096)
+Full-Scale – 1 LSB
••• •••
••• •••
••• •••
801h
+6 × VREF × (2049/4096)
Midscale + 1 LSB
800h
+6 × VREF × (2048/4096)
Midscale
7FFh
+6 × VREF × (2047/4096)
Midscale – 1 LSB
••• •••
••• •••
••• •••
000h
0
0
Table 4. Unipolar Output vs Twos Complement Code Using Single Power Supply with Gain = 6
BTC CODE
NOMINAL OUTPUT
DESCRIPTION
7FFh
+6 × VREF × (4095/4096)
+Full-Scale – 1 LSB
••• •••
••• •••
••• •••
001h
+6 × VREF × (2049/4096)
Midscale + 1 LSB
000h
+6 × VREF × (2048/4096)
Midscale
FFFh
+6 × VREF × (2047/4096)
Midscale – 1 LSB
••• •••
••• •••
••• •••
800h
0
0
The data written to the Gain Register are always in straight binary, data to the Zero Register are in twos
complement, and data to all other control registers are as specified in the definitions, regardless of the USB/BTC
pin status.
In reading operation, the read-back data are in the same format as written.
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OFFSET DACS
There are two 12-bit Offset DACs: one for Group A, and one for Group B. The Offset DACs allow the entire
output curve of the associated DAC groups to be shifted by introducing a programmable offset. This offset allows
for asymmetric bipolar operation of the DACs or unipolar operation with bipolar supplies. Thus, subject to the
limitations of headroom, it is possible to set the output range of Group A and/or Group B to be unipolar positive,
unipolar negative, symmetrical bipolar, or asymmetrical bipolar, as shown in Table 5 and Table 6. Increasing the
digital input codes for the offset DAC shifts the outputs of the associated channels in the negative direction. The
default codes for the Offset DACs in the DAC7718 are factory trimmed to provide optimal offset and gain
performance for the default output range and span of symmetric bipolar operation. When the output range is
adjusted by changing the value of the Offset DAC, an extra offset is introduced as a result of the linearity and
offset errors of the Offset DAC. Therefore, the actual shift in the output span may vary slightly from the ideal
calculations. For optimal offset and gain performance in the default symmetric bipolar operation, the Offset DAC
input codes should not be changed from the default power-on values. The maximum allowable offset depends on
the reference and the power supply. If INPUT_CODE from Equation 1 or DAC_DATA_CODE from Equation 2 is
set to 0, then these equations simplify to Equation 3:
VOUT = -VREF ´ (Gain - 1) ´
OFFSETDAC_CODE
4096
(3)
This equation shows the transfer function of the Offset DAC to the output of the DAC channels. In any case, the
analog output must not go beyond the specified range shown in the Analog Outputs section. After power-on or
reset, the Offset DAC is set to the value defined by the selected data format and the selected analog output
voltage. If the DAC gain setting is changed, the offset DAC code is reset to the default value corresponding to
the new DAC gain setting. Refer to the Power-On Reset and Hardware Reset sections for details.
For single-supply operation (AVSS = 0V), the Offset DAC is turned off, and the output amplifier is in a Hi-Z state.
The OFFSET-x pin must be connected to the AGND-x pin through a low-impedance connection (see the Layout
section for details). For dual-supply operation, this pin provides the output of the Offset DAC. The OFFSET-x pin
is not intended to drive an external load. See Figure 98 for the internal Offset DAC and output amplifier
configuration.
Table 5. Example of Offset DAC Codes and Output Ranges with Gain = 6 and VREF = 5V
(1)
(2)
OFFSET DAC
CODE
OFFSET DAC
VOLTAGE
DAC CHANNELS MFS (1)
VOLTAGE
DAC CHANNELS PFS (1)
VOLTAGE
99Ah (2)
3.0V
–15V
+15V – 1 LSB
+30V – 1 LSB
000h
0V
0V
FFFh
~5.0V
–25V
+5V – 1 LSB
666h
~2.0V
–10V
+20V – 1 LSB
CCDh
~4.0V
–20V
+10V – 1 LSB
MFS = minus full-scale; PFS = plus full-scale.
This is the default code for symmetric bipolar operation; actual codes may vary ±1 LSB. Codes are in straight binary format.
Table 6. Example of Offset DAC Codes and Output Ranges with Gain = 4 and VREF = 5V
(1)
(2)
OFFSET DAC
CODE
OFFSET DAC
VOLTAGE
DAC CHANNELS MFS (1)
VOLTAGE
DAC CHANNELS PFS (1)
VOLTAGE
AABh (2)
~3.33333V
–10V
+10V – 1 LSB
000h
0V
0V
+20V – 1 LSB
FFFh
~5.0V
–15V
+5V – 1 LSB
555h
~1.666V
–5V
+15V – 1 LSB
800h
2.5V
–7.5V
+12.5V – 1 LSB
D55h
~4.1666V
–12.5V
+7.5V – 1 LSB
MFS = minus full-scale; PFS = plus full-scale.
This is the default code for symmetric bipolar operation; actual codes may vary ±1 LSB. Codes are in straight binary format.
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VOUT = GAIN x V1 - (GAIN - 1) x VOFF
DAC
Channel
V1
VOUT
AGND-x
Offset
DAC
VOFF
OFFSET
Figure 98. Output Amplifier and Offset DAC
OUTPUT AMPLIFIERS
The output amplifiers can swing to 0.5V below the positive supply and 0.5V above the negative supply. This
condition limits how much the output can be offset for a given reference voltage. The maximum range of the
output for ±17V power and a +5.5V reference is –16.5V to +16.5V for gain = 6.
Each output amplifier is implemented with individual over-current protection. The amplifier is clamped at 8mA,
even if the output current goes over 8mA.
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GENERAL-PURPOSE INPUT/OUTPUT PINS (GPIO-0 to GPIO-2)
The GPIO pins are general-purpose, bidirectional, digital input/outputs, as shown in Figure 99. When a GPIO pin
acts as an output, the pin status is determined by the corresponding GPIO bit in the GPIO Register. The pin
output is high-impedance when the GPIO bit is set to '1', and is logic low when the GPIO bit is cleared to '0'.
Note that a pull-up resistor to IOVDD is required when using a GPIO pin as an output. When a GPIO pin acts as
an input, the digital value on the pin is acquired by reading the corresponding GPIO bit. After power-on reset, or
any forced hardware or software reset, the GPIO bits are set to '1', and the GPIO pins are in a high-impedance
state. If not used, the GPIO pins must be tied to either DGND or to IOVDD through a pull-up resistor. Leaving the
GPIO pins floating can cause high IOVDD supply currents.
+V
GPIO-n
Enable
Bit GPIO-n (when writing)
Bit GPIO-n (when reading)
Figure 99. GPIO-n Pin
ANALOG OUTPUT PIN (CLR)
The CLR pin is an active low input that should be high for normal operation. When this pin is in logic '0', all VOUT
outputs connect to AGND-x through internal 15kΩ resistors and are cleared to 0V, and the output buffer is in a
Hi-Z state. While CLR is low, all LDAC pulses are ignored. When CLR is taken high again while the LDAC is
high, the DAC outputs remain cleared until LDAC is taken low. However, if LDAC is tied low, taking CLR back to
high sets the DAC output to the level defined by the value of the DAC latch. The contents of the Zero Registers,
Gain Registers, Input Data Registers, DAC Data Registers, and DAC latches are not affected by taking CLR low.
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POWER-ON RESET
The DAC7718 contains a power-on reset circuit that controls the output during power-on and power down. This
feature is useful in applications where the known state of the DAC output during power-on is important. The
Offset DAC Registers, DAC Data Registers, and DAC latches are loaded with the value defined by the RSTSEL
pin, as shown in Table 7. The Gain Registers and Zero Registers are loaded with default values. The Input Data
Register is reset to 000h, independent of the RSTSEL state.
Table 7. Bipolar Output Reset Values for Dual Power-Supply Operation
(1)
RSTSEL PIN
USB/BTC PIN
INPUT FORMAT
VALUE OF DAC
DATA REGISTER
AND DAC LATCH
VALUE OF OFFSET
DAC REGISTER
FOR GAIN = 6 (1)
DGND
DGND
Straight Binary
000h
99Ah
–Full-Scale
VOUT
IOVDD
DGND
Straight Binary
800h
99Ah
0V
DGND
IOVDD
Twos Complement
800h
19Ah
–Full-Scale
IOVDD
IOVDD
Twos Complement
000h
19Ah
0V
Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the error for symmetrical output. The default value may vary
no more than ±1 LSB from the nominal number listed in this table.
In single-supply operation, the Offset DAC is turned off and the output is unipolar. The power-on reset is defined
as shown in Table 8.
Table 8. Unipolar Output Reset Values for Single Power-Supply Operation
RSTSEL PIN
USB/BTC PIN
INPUT FORMAT
VALUE OF DAC DATA
REGISTER AND DAC
LATCH
DGND
DGND
Straight Binary
000h
0V
IOVDD
DGND
Straight Binary
800h
Midscale
DGND
IOVDD
Twos Complement
800h
0V
IOVDD
IOVDD
Twos Complement
000h
Midscale
VOUT
HARDWARE RESET
When the RST pin is low, the device is in hardware reset. All the analog outputs (VOUT-0 to VOUT-7), the DAC
registers, and the DAC latches are set to the reset values defined by the RSTSEL pin as shown in Table 7 and
Table 8. In addition, the Gain and Zero Registers are loaded with default values, communication is disabled, and
the signals on CS and SDI are ignored (note that SDO is in a high-impedance state). The Input Data Register is
reset to 000h, independent of the RSTSEL state. On the rising edge of RST, the analog outputs (VOUT-0 to
VOUT-7) maintain the reset value as defined by the RSTSEL pin until a new value is programmed. After RST
goes high, the serial interface returns to normal operation. CS must be set to a logic high whenever RST is used.
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UPDATING THE DAC OUTPUTS
Depending on the status of both CS and LDAC, and after data have been transferred into the DAC Data
registers, the DAC outputs can be updated either in asynchronous mode or synchronous mode. This update
mode is established at power-on. If asynchronous mode is desired, the LDAC pin must be permanently tied low
before power is applied to the device. If synchronous mode is desired, LDAC must be logic high before and
during power-on.
The DAC7718 updates a DAC latch only if it has been accessed since the last time LDAC was brought low or if
the LD bit is set to '1', thereby eliminating any unnecessary glitch. Any DAC channels that were not accessed are
not loaded again. When the DAC latch is updated, the corresponding output changes to the new level
immediately.
Asynchronous Mode
In this mode, the LDAC pin is set low at power-up. This action places the DAC7718 into Asynchronous mode,
and the LD bit and LDAC signal are ignored. When the correction engine is off (SCE bit = '0'), the DAC Data
Registers and DAC latches are updated immediately when CS goes high. When the correction engine is on (SCE
bit = '1'), each DAC latch is updated individually when the correction engine updates the corresponding DAC
Data Register.
Synchronous Mode
To use this mode, set LDAC high before CS goes low, and then take LDAC low or set the LD bit to '1' after CS
goes high. If LDAC goes low or if the LD bit is set to '1' when SCE = '0', all DAC latches are updated
simultaneously. If LDAC goes low or if the LD bit is set to '1' when SCE = '1', all DAC latches are updated
simultaneously after the correction engine has updated the corresponding DAC register.
In this mode, when LDAC stays high, the DAC latch is not updated; therefore, the DAC output does not change.
The DAC latch is updated by taking LDAC low (or by setting the LD bit in the Configuration Register to '1') any
time after the delay of t9 from the rising edge of CS. If the timing requirement of t9 is not satisfied, invalid data are
loaded. Refer to the Timing Diagrams and the Configuration Register (Table 11) for details.
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MONITOR OUTPUT PIN (VMON)
The VMON pin is the channel monitor output. It can be either high-impedance or monitor any one of the DAC
outputs, auxiliary analog inputs, offset DAC outputs, or reference buffer outputs. The channel monitor function
consists of an analog multiplexer addressed via the serial interface, allowing any channel output, reference buffer
output, auxiliary analog inputs, or offset DAC output to be routed to the VMON pin for monitoring using an external
ADC. The monitor function is controlled by the Monitor Register, which allows the monitor output to be enabled
or disabled. When disabled, the monitor output is high-impedance; therefore, several monitor outputs may be
connected in parallel with only one enabled at a time.
Note that the multiplexer is implemented as a series of analog switches. Care should be taken to ensure the
maximum current from the VMON pin must not be greater than the given specification because this could
conceivably cause a large amount of current to flow from the input of the multiplexer (that is, from VOUT-X) to the
output of the multiplexer (VMON). Refer to the Monitor Register section and Table 12 for more details.
ANALOG INPUT PINS (AIN-0 and AIN-1)
Pins AIN-0 and AIN-1 are two analog inputs that directly connect to the analog mux of the analog monitor output.
When AIN-0 or AIN-1 is accessed, it is routed via the mux to the VMON pin. Thus, one external ADC channel can
monitor eight DACs plus two extra external analog signals, AIN-0 and AIN-1.
POWER-DOWN MODE
The DAC7718 is implemented with a power-down function to reduce power consumption. Either the entire device
or each individual group can be put into power-down mode. If the proper power-down bit (PD-x) in the
Configuration Register is set to '1', the individual group is put into power down mode. During power-down mode,
the analog outputs (VOUT-0 to VOUT-7) connect to AGND-X through an internal 15kΩ resistor, and the output
buffer is in Hi-Z status. When the entire device is in power-down, the bus interface remains active in order to
continue communication and receive commands from the host controller, but all other circuits are powered down.
The host controller can wake the device from power-down mode and return to normal operation by clearing the
PD-x bit; it takes 200ms or less for recovery to complete.
POWER-ON RESET SEQUENCING
The DAC7718 permanently latches the status of some of the digital pins at power-on. These digital levels should
be well-defined before or while the digital supply voltages are applied. Therefore, it is advised to have a pull up
resistor to IOVDD for the digital initialization pins (LDAC, CLR, RST, CS, and RSTSEL) to ensure that these levels
are set correctly while the digital supplies are raised.
For proper power-on initialization of the device, IOVDD and the digital pins must be applied before or at the same
time as DVDD. If possible, it is preferred that IOVDD and DVDD can be connected together in order to simplify the
supply sequencing requirements. Pull-up resistors should go to either supply. AVDD should be applied after the
digital supplies (IOVDD and DVDD) and digital initialization pins (LDAC, CLR, RST, CS, and RSTSEL). AVSS can
be applied at the same time as or after AVDD. The REF-x pins must be applied last.
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SERIAL INTERFACE
The DAC7718 is controlled over a versatile, three-wire serial interface that operates at clock rates of up to
50MHz and is compatible with SPI, QSPI™, Microwire™, and DSP™ standards.
SPI Shift Register
The SPI Shift Register is 24 bits wide. Data are loaded into the device MSB first as a 24-bit word under the
control of the serial clock input, SCLK. The SPI Shift Register consists of a read/write bit, five register address
bits, 12 data bits, and six reserve bits for future devices, as shown in Table 9. The falling edge of CS starts the
communication cycle. The data are latched into the SPI Shift Register on the falling edge of SCLK while CS is
low. When CS is high, the SCLK and SDI signals are blocked and the SDO pin is in a high-impedance state. The
contents of the SPI shifter register are decoded and transferred to the proper internal registers on the rising edge
of CS. The timing for this operation is shown in the Timing Diagrams section.
The serial interface works with both a continuous and non-continuous serial clock. A continuous SCLK source
can only be used if CS is held low for the correct number of clock cycles. In gated clock mode, a burst clock
containing the exact number of clock cycles must be used and CS must be taken high after the final clock in
order to latch the data.
The serial interface requires CS to be logic high during the power-on sequencing; therefore, it is advised to have
a pullup resistor to IOVDD on the CS pin. Refer to the Power-On Reset Sequencing section for further details.
Stand-Alone Operation
The serial clock can be a continuous or a gated clock. The first falling edge of CS starts the operation cycle.
Exactly 24 falling clock edges must be applied before CS is brought back high again. If CS is brought high before
the 24th falling SCLK edge, then the data written are not transferred into the internal registers. If more than 24
falling SCLK edges are applied before CS is brought high, then the last 24 bits are used. The device internal
registers are updated from the Shift Register on the rising edge of CS. In order for another serial transfer to take
place, CS must be brought low again.
When the data have been transferred into the chosen register of the addressed DAC, all DAC latches and analog
outputs can be updated by taking LDAC low.
Daisy-Chain Operation
For systems that contain more than one device, the SDO pin can be used to daisy-chain multiple devices
together. Daisy-chain operation can be useful in system diagnostics and in reducing the number of serial
interface lines. Note that before daisy-chain operation can begin, the SDO pin must be enabled by setting the
SDO disable bit (DSDO) in the Configuration Register to '0'; this bit is cleared by default.
The DAC7718 provides two modes for daisy-chain operation: normal and sleep. The SLEEP bit in the SPI Mode
register determines which mode is used.
In Normal mode (SLEEP bit = '0'), the data clocked into the SDI pin are transferred into the Shift Register. The
first falling edge of CS starts the operating cycle. SCLK is continuously applied to the SPI Shift Register when CS
is low. If more than 24 clock pulses are applied, the data ripple out of the Shift Register and appear on the SDO
line. These data are clocked out on the rising edge of SCLK and are valid on the falling edge. By connecting the
SDO pin of the first device to the SDI input of the next device in the chain, a multiple-device interface is
constructed. Each device in the system requires 24 clock pulses. Therefore, the total number of clock cycles
must equal 24 × N, where N is the total number of DAC7718s in the chain. When the serial transfer to all devices
is complete, CS is taken high. This action latches the data from the SPI Shift Registers to the device internal
registers for each device in the daisy-chain, and prevents any further data from being clocked in. The serial clock
can be a continuous or a gated clock. Note that a continuous SCLK source can only be used if CS is held low for
the correct number of clock cycles. For gated clock mode, a burst clock containing the exact number of clock
cycles must be used and CS must be taken high after the final clock in order to latch the data.
In Sleep mode (SLEEP bit = '1'), the data clocked into SDI are routed to the SDO pin directly; the Shift Register
is bypassed. The first falling edge of CS starts the operating cycle. When SCLK is continuously applied with CS
low, the data clocked into the SDI pin appear on the SDO pin almost immediately (with approximately a 5 ns
delay; see the Timing Diagrams section); there is no 24 clock delay, as there is in normal operting mode. While
in Sleep mode, no data bits are clocked into the Shift Register, and the device does not receive any new data or
commands. Putting the device into Sleep mode eliminates the 24 clock delay from SDI to SDO caused by the
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Shift Register, thus greatly speeding up the data transfer. For example, consider three DAC7718s (A, B, and C)
in a daisy-chain configuration. The data from the SPI controller are transferred first to A, then to B, and finally to
C. In normal daisy-chain operation, a total of 72 clocks are needed to transfer one word to C. However, if A and
B are placed into Sleep mode, the first 24 data bits are directly transferred to C (through A and B); therefore, only
24 clocks are needed.
To wake the device up from sleep mode and return to normal operation, either one of following methods can be
used:
1. Pull the WAKEUP pin low, which forces the SLEEP bit to '0' and returns the device to normal operating
mode.
2. Use the W2 bit and the CS pin.
When the W2 bit = '1', if CS is applied with no more than one falling edge of SCLK, then the rising edge of CS
wakes the device from sleep mode back to normal operation. However, the device will not wake-up if more than
one falling edge of SCLK exists while CS is low.
Read-Back Operation
The READ command is used to start read-back operation. However, before read-back operation can be initiated,
the SDO pin must be enabled by setting the DSDO bit in the Configuration Register to '0'; this bit is cleared by
default. Read-back operation is then started by executing a READ command (R/W bit = '1', see Table 9). Bits A4
to A0 in the READ command select the register to be read. The remaining data in the command are don’t care
bits. During the next SPI operation, the data appearing on the SDO output are from the previously addressed
register. For a read of a single register, a NOP command can be used to clock out the data from the selected
register on SDO. Multiple registers can be read if multiple READ commands are issued. The readback diagram
in Figure 100 shows the read-back sequence.
Single Reading
CS
SCLK
R/W = ‘1’
R/W = ‘0’
DB0
DB23
SDI
DB0
DB23
READ Command Specifies
Register to be Read
NOP Command
(write ‘1’ to NOP bit)
DB0
DB23
SDO
DB0
DB23
Undefined
Data from
Selected Register
Multiple Readings
CS
SCLK
R/W = ‘1’
SDI
R/W = ‘1’
DB23
DB0
Command to Read
Register A
SDO
DB23
DB0
R/W = ‘1’
DB23
DB0
Command to Read
Register B
DB23
Undefined
R/W = ‘0’
DB23
DB0
DB23
Command to Read
Register C
DB0
DB23
Data from
Register A
DB0
DB23
NOP Command
(write ‘1’ to NOP bit)
DB23
Data from
Register B
= Don’t Care
DB0
Command
DB0
Data from
Register C
DB0
DB23
DB0
Undefined
Bit 23 = MSB
Bit 0 = LSB
Figure 100. Read-Back Operation
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SPI SHIFT REGISTER
The SPI Shift Register is 24 bits wide, as shown in Table 9. The register mapping is shown in Table 10; X = don't
care—writing to it has no effect, reading it returns '0'.
Table 9. Shift Register Format
MSB
DB23
DB22
DB21
DB20
DB19
DB18
DB17
DB16
DB15:DB4
DB3:DB0
R/W
X
X
A4
A3
A2
A1
A0
DATA
X
R/W
Indicates a read from or a write to the addressed register.
R/W = '0' sets a write operation and the data are written to the specified register.
R/W = '1' sets a read-back operation. Bits A4 to A0 select the register to be read. The remaining bits
are don’t care bits. During the next SPI operation, the data appearing on SDO pin are from the
previously addressed register.
A4:A0
Address bits that specify which register is accessed.
DATA
12 data bits
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Table 10. Register Map
ADDRESS BITS
DATA BITS
A4 A3 A2 A1 A0
D15
D14
D13
A/B
LD
RST
GPIO-2
GPIO-1
GPIO-0
D12
PD-A
D11
PD-B
D10
SCE
D9
X
D8
D7
GAIN-A GAIN-B
D6
DSDO
D5
REGISTER
X (1)
Configuration
Register
X (1)
Monitor Register
0
0
0
0
0
0
0
0
1
0
0
0
1
0
0
0
0
1
1
OS11:OS0, X, X, X, X (2)
Offset DAC-A
Data
0
0
1
0
0
OS11:OS0, X, X, X, X (2)
Offset DAC-B
Data
0
0
1
0
1
Reserved (3)
0
0
1
1
0
0
0
1
1
0
1
0
0
0
1
0
0
1
0
X (1)
W2
D3:D0
0
Analog Monitor Select
NOP
D4
GPIO Register
Reserved
Reserved (3)
SPI MODE
1
DB11:DB0, X, X, X, X
Broadcast
0
DB11:DB0, X, X, X, X
DAC-0
0
1
DB11:DB0, X, X, X, X
DAC-1
0
1
0
DB11:DB0, X, X, X, X
DAC-2
1
0
1
1
DB11:DB0, X, X, X, X
DAC-3
0
1
1
0
0
DB11:DB0, X, X, X, X
DAC-4
0
1
1
0
1
DB11:DB0, X, X, X, X
DAC-5
0
1
1
1
0
DB11:DB0, X, X, X, X
DAC-6
0
1
1
1
1
DB11:DB0, X, X, X, X
DAC-7
1
0
0
0
0
Z11:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-0
1
1
0
0
0
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-0
1
0
0
0
1
Z11:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-1
1
1
0
0
1
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-1
1
0
0
1
0
Z11:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-2
1
1
0
1
0
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-2
1
0
0
1
1
Z11:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-3
1
1
0
1
1
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-3
1
0
1
0
0
Z11:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-4
1
1
1
0
0
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-4
1
0
1
0
1
Z1:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-5
1
1
1
0
1
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-5
1
0
1
1
0
Z11:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-6
1
1
1
1
0
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-6
1
0
1
1
1
Z11:Z0, X, X, X, X, default = 0 (000h), twos complement
Zero Register-7
1
1
1
1
1
G11:G0, X, X, X, X, default = 2048 (800h), straight binary
Gain Register-7
(1)
(2)
(3)
48
SLEEP
X = don't care—writing to this bit has no effect; reading the bit returns '0'.
Table 7 lists the default values for a dual power supply. Offset DAC A and Offset DAC B are trimmed in manufacturing to minimize the
error for symmetrical output. The default value may vary no more than ±1 LSB from the nominal number listed in Table 7. For a single
power supply, the Offset DACs are turned off.
Writing to a reserved bit has no effect; reading the bit returns '0'.
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INTERNAL REGISTERS
The DAC7718 internal registers consist of the Configuration Register, the Monitor Register, the DAC Input Data
Registers, the Zero Registers, the DAC Data Registers, and the Gain Registers, and are described in the
following section.
The Configuration Register specifies which actions are performed by the device. Table 11 shows the details.
Table 11. Configuration Register (Default = 800h)
BIT
D15
NAME
A/B
DEFAULT
VALUE
DESCRIPTION
1
A/B bit.
When A/B = '0', reading DAC-x returns the value in the Input Data Register.
When A/B = '1', reading DAC-x returns the value in the DAC Data Register.
When the correction engine is enabled, the data returned from the Input Data Register is the original data written to the
bus, and the value in the DAC Data Register is the corrected data.
D14
LD
0
Synchronously update DACs bit.
When LDAC is tied high, setting LD = '1' at any time after the write operation and the correction process complete
synchronously updates all DAC latches with the content of the corresponding DAC Data Register, and sets VOUT to a new
level. The DAC7718 updates the DAC latch only if it has been accessed since the last time LDAC was brought low or the
LD bit was set to '1', thereby eliminating unnecessary glitch. Any DACs that were not accessed are not reloaded. After
updating, the bit returns to '0'. When the correction engine is turned off, bit LD can be set to '1' any time after the writing
operation is complete; the DAC latch is immediately updated when bit LD is set. When the LDAC pin is tied low, this bit is
ignored.
D13
RST
0
Software reset bit.
Set the RST bit to '1' to reset the device; functions the same as a hardware reset. After reset completes, the RST bit
returns to '0'.
0
Power-down bit for Group A (DAC-0, DAC-1, DAC-2, and DAC-3).
Setting the PD-A bit to '1' places Group A (DAC-0, DAC-1, DAC-2, and DAC-3) into power-down operation. All output
buffers are in Hi-Z and all analog outputs (VOUT-X) connect to AGND-A through an internal 15-kΩ resistor. The interface is
still active.
Setting the PD-A bit to '0' returns group A to normal operation.
0
Power-down bit for Group B (DAC-4, DAC-5, DAC-6, and DAC-7).
Setting the PD-B bit to '1' places Group B (DAC-4, DAC-5, DAC-6, and DAC-7) into power-down operation. All output
buffers are in Hi-Z and all analog outputs (VOUT-X) connect to AGND-B through an internal 15-kΩ resistor. The interface is
still active.
Setting the PD-B bit to '0' returns group B to normal operation.
D12
D11
PD-A
PD-B
D10
SCE
0
System-calibration enable bit.
Set the SCE bit to '1' to enable the correction engine. When the engine is enabled, the input data are adjusted by the
correction engine according to the contents of the corresponding Gain Register and Zero Register. The results are
transferred to the corresponding DAC Data Register, and finally loaded into the DAC latch, which sets the VOUT-x pin
output level.
Set the SCE bit to '0' to turn off the correction engine. When the engine is turned off, the input data are transferred to the
corresponding DAC Data Register immediately, and then loaded into the DAC latch, which sets the output voltage. Refer
to the User Calibration for Zero-Code Error and Gain Error section for details.
D9
—
0
Reserved. Writing to this bit has no effect; reading this bit returns '0'.
D8
GAIN-A
0
Gain bit for Group A (DAC-0, DAC-1, DAC-2, and DAC-3). Updating this bit to a new value automatically resets the Offset
DAC-A Register to the factory-trimmed value for the new gain setting.
Set the GAIN-A bit to '0' for an output span = 6 × REF-A.
Set the GAIN-A bit to '1' for an output span = 4 × REF-A.
D7
GAIN-B
0
Gain bit for Group B (DAC-4, DAC-5, DAC-6, and DAC-7). Updating this bit to a new value automatically resets the Offset
DAC-B Register to the factory-trimmed value for the new gain setting.
Set the GAIN-B bit to '0' for an output span = 6 × REF-B.
Set the GAIN-B bit to '1' for an output span = 4 × REF-B.
D6
DSDO
0
Disable SDO bit.
Set the DSDO bit to '0' to enable the SDO pin (default). The SDO pin works as a normal SPI output.
Set the DSDO bit to '1' to disable the SDO pin. The SDO pin is always in a Hi-Z state no matter what the status of the CS
pin is.
D5
NOP
0
No operation bit.
During a write operation, setting the NOP bit to '1' has no effect (the bit returns to '0' when the write operation completes).
Setting the NOP bit to '0', returns the device to normal operation.
During a read operation, the bit always returns “0”
D4
W2
0
Second wake-up operation bit.
If the WAKEUP pin is high, an alternative method to wake-up the device from sleep in SPI is by using the CS pin. When
W2 = '1', the rising edge of CS restores the device from sleep mode to normal operation, if no more than one falling edge
of SCLK exists while CS is low. However, the device will not wake up if more than one falling edge of SCLK exists. Setting
the W2 bit to '0' disables this function, and the rising edge of CS does not wake up the device.
If the WAKEUP is low, this bit is ignored and the device is always in normal mode.
D3:D0
—
0
Reserved. Writing to these bits has no effect; reading these bits returns '0'.
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Monitor Register (default = 000h).
The Monitor Register selects one of the DAC outputs, auxiliary analog inputs, reference buffer outputs, or offset
DAC outputs to be monitored through the VMON pin. When bits [D15:D4] = '0', the monitor is disabled and VMON is
in a Hi-Z state.
Note that if any value is written other than those specified in Table 12, the Monitor Register stores the invalid
value; however, the VMON pin is forced into a Hi-Z state.
Table 12. Monitor Register (Default = 000h)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3:D0
VMON CONNECTS TO
0
0
0
0
0
0
0
0
0
0
0
1
X (1)
Reference buffer B output
0
0
0
0
0
0
0
0
0
0
1
0
X
Reference buffer A output
0
0
0
0
0
0
0
0
0
1
0
1
X
Offset DAC B output
0
0
0
0
0
0
0
0
0
1
1
0
X
Offset DAC A output
0
0
0
0
0
0
0
0
0
1
0
0
X
AIN-0
0
0
0
0
0
0
0
0
1
0
0
0
X
AIN-1
0
0
0
0
0
0
0
1
0
0
0
0
X
DAC-0
0
0
0
0
0
0
1
0
0
0
0
0
X
DAC-1
0
0
0
0
0
1
0
0
0
0
0
0
X
DAC-2
0
0
0
0
1
0
0
0
0
0
0
0
X
DAC-4
0
0
0
1
0
0
0
0
0
0
0
0
X
DAC-4
0
0
1
0
0
0
0
0
0
0
0
0
X
DAC-5
0
1
0
0
0
0
0
0
0
0
0
0
X
DAC-6
1
0
0
0
0
0
0
0
0
0
0
0
X
DAC-7
0
0
0
0
0
0
0
0
0
0
0
0
X
Monitor function disabled, Hi-Z (default)
(1)
X = don't care.
BLANKSPACE
GPIO Register (default = E00h).
The GPIO Register determines the status of each GPIO pin.
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
GPIO-2
GPIO-1
GPIO-0
X
X
X
X
X
X
X
X
X
X
X
X
X
GPIO-2:0
For write operations, the GPIO-n pin operates as an output. Writing a '1' to the GPIO-n bit sets the
GPIO-n pin to high impedance, and writing a '0' sets the GPIO-n pin to logic low. An external
pull-up resistor is required when using the GPIO-n pin as an output.
For read operations, the GPIO-n pin operates as an input. Read the GPIO-n bit to receive the
status of the corresponding GPIO-n pin. Reading a '0' indicates that the GPIO-n pin is low, and
reading a '1' indicates that the GPIO-n pin is high.
After power-on reset, or any forced hardware or software reset, all GPIO-n bits are set to '1', and
the GPIO pins are in a high impedance state.
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Offset DAC-A/B Registers (default = 99Ah for dual supplies or 000h for single supplies).
The Offset DAC-A and Offset DAC-B registers contain, by default, the factory-trimmed Offset DAC code
providing optimal offset and span for symmetric bipolar operation when dual supplies are detected, and contain
code 000h when a single supply is detected.
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
OS11
OS10
OS9
OS8
OS7
OS6
OS5
OS4
OS3
OS2
OS1
OS0
X
X
X
X
OS11:0
For dual-supply operation, the default code for a gain of 6 is 99Ah with a ±1 LSB variation,
depending on the linearity of each Offset DAC. The default code for a gain of 4 is AABh with a ±1
LSB variation. The default codes of Offset DAC-A and Offset DAC-B registers are independently
factory trimmed for both gains of 6 and 4.
When single-supply operation is present, writing to these registers is ignored and reading returns
000h. When dual-supply operation is present, updating the GAIN-A (GAIN-B) bit on the
configuration register automatically reloads the factory-trimmed code into the Offset DAC-A (Offset
DAC-B) register for the new GAIN-A (GAIN-B) setting. See the Offset DACs for further details.
BLANKSPACE
SPI MODE Register (default = 000h).
The SPI Mode Register is used to put the device into SPI sleep mode.
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
SLEEP
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
SLEEP
Set the SLEEP bit to '1' to put the device into SPI sleep mode.
When the SLEEP bit = '0', the SPI is in normal mode. The bit is cleared ('0') after a hardware reset
(through the RST pin) or if the WAKEUP pin is low.
For normal SPI operation, the data entering the SDI pin is transferred into the Shift Register.
However, for SPI sleep mode, the Shift Register is bypassed. The data entering into the SDI pin
are directly transferred to the SDO pin instead of the Shift Register.
BLANKSPACE
Broadcast Register.
The DAC7718 broadcast register can be used to update all eight DAC register channels simultaneously using
data bits D15:D4. This write-only register uses address A4:A0 = 07h, and is only available when the SCE bit = '0'
(default). If the SCE bit = '1', this register is ignored. Reading this register always returns 000h.
BLANKSPACE
Input Data Register for DAC-n, where n = 0 to 7 (default = 000h).
This register stores the DAC data written to the device when the SCE bit = '1' and is controlled by the correction
engine. When the SCE bit = '0' (default), the DAC Data Register stores the DAC data written to the device. When
the data are loaded into the corresponding DAC latch, the DAC output changes to the new level defined by the
DAC latch. The default value after power-on or reset is 000h.
Table 13. DAC-n (1) Input Data Register
MSB
D15
DB11
(1)
(2)
(2)
LSB
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
X
X
X
X
n = 0, 1, 2, 3, 4, 5, 6, or 7.
DB11:DB0 are the DAC data bits.
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Zero Register n, where n = 0 to 7 (default = 000h).
The Zero Register stores the user-calibration data that are used to eliminate the offset error. The data are 12 bits
wide, 1 LSB/step, and the total adjustment is –2048 LSB to +2047 LSB, or ±50% of full-scale range. The Zero
Register uses a twos complement data format.
Table 14. Zero Register
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Z11
Z10
Z9
Z8
Z7
Z6
Z5
Z4
Z3
Z2
Z1
Z0
X
X
X
X
Z11:Z0—OFFSET BITS
ZERO ADJUSTMENT
7FFh
+2047 LSB
7FEh
+2046 LSB
••• ••• •••
••• ••• •••
001h
+1 LSB
000h
0 LSB (default)
FFFh
–1 LSB
••• ••• •••
••• ••• •••
801h
–2047 LSB
800h
–2048 LSB
BLANKSPACE
Gain Register n, where n = 0 to 7 (default = 800h).
The Gain Register stores the user-calibration data that are used to eliminate the gain error. The data are 12 bits
wide, 0.0015% FSR/step, and the total adjustment range 0.5 to 1.5. The Gain Register uses a straight binary
data format.
Table 15. Gain Register
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
G11
G10
G9
G8
G7
G6
G5
G4
G3
G2
G1
G0
X
X
X
X
52
G11:G0—GAIN-CODE BITS
GAIN ADJUSTMENT COEFFICIENT
FFFh
1.499985
FFEh
1.499969
••• ••• •••
••• ••• •••
801h
1.000015
800h
1 (default)
7FFh
0.999985
••• ••• •••
••• ••• •••
001h
0.500015
000h
0.5
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APPLICATION INFORMATION
BASIC OPERATION
SDI
CS
SCLK
54
53
52
51
50
49
NC
NC
55
USB/BTC
SDO
2 NC
RSTSEL
LDAC
1 AVDD
56
RSTSEL
57
NC
SCLK
58
NC
CS
59
10kW
DGND
SDI
60
DVDD
SDO
61
1 mF
DVDD
LDAC
62
1mF
IOVDD
WAKEUP
10mF
63
WAKEUP
AVDD
64
NC
IOVDD
The DAC7718 is a highly-integrated device with high-performance reference buffers and output buffers, greatly
reducing the printed circuit board (PCB) area and production cost. On-chip reference buffers eliminate the need
for a negative external reference. Figure 101 shows a basic application for the DAC7718.
AVDD 48
AVDD
10mF
NC 47
AIN-0
3 AIN-0
VOUT-3
4 VOUT-3
VOUT-4 45
VOUT-4
REF-A
5 REF-A
REF-B 44
REF-B
VOUT-2
6 VOUT-2
VOUT-5 43
VOUT-5
VOUT-1
7 VOUT-1
VOUT-6 42
VOUT-6
AIN-1 46
8 AGND-A
AIN-1
AGND-B 41
DAC7718
9 AGND-A
OFFSET-A
10 OFFSET-A
OFFSET-B 39
11 VOUT-0
VOUT-7 38
12 AVSS
24
NC
23
NC
22
GPIO-0
21
GPIO-1
20
DGND
19
NC
18
DGND
17
16 NC
NC
DVDD
NC 34
NC
15 NC
NC
NC 35
RST
14 VMON
CLR
NC 36
GPIO-2
VMON
13 NC
NC
AVSS
OFFSET-B
VOUT-7
AVSS 37
NC
10mF
VOUT-0
AGND-B 40
25
26
27
28
29
30
31
32
10mF
AVSS
NC 33
DVDD
10kW
RST
CLR
1mF
10kW
10kW
NOTES: AVDD = +15V, AVSS = -15V, DVDD = +5V, IOVDD = +1.8V to +5V, REF-A = +5V, and REF-B = +2.5V.
NOTES: The OFFSET-A and OFFSET-B pins must be connected to the AGND pin when used in unipolar operation.
Figure 101. Basic Application Example
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PRECISION VOLTAGE REFERENCE SELECTION
To achieve the optimum performance from the DAC7718 over the full operating temperature range, a precision
voltage reference must be used. Careful consideration should be given to the selection of a precision voltage
reference. The DAC7718 has two reference inputs, REF-A and REF-B. The voltages applied to the reference
inputs are used to provide a buffered positive reference for the DAC cores. Therefore, any error in the voltage
reference is reflected in the outputs of the device. There are four possible sources of error to consider when
choosing a voltage reference for high-accuracy applications: initial accuracy, temperature coefficient of the output
voltage, long-term drift, and output voltage noise. Initial accuracy error on the output voltage of an external
reference can lead to a full-scale error in the DAC. Therefore, to minimize these errors, a reference with low
initial accuracy error specification is preferred. Long-term drift is a measure of how much the reference output
voltage drifts over time. A reference with a tight, long-term drift specification ensures that the overall solution
remains relatively stable over its entire lifetime. The temperature coefficient of a reference output voltage affects
the output drift when the temperature changes. Choose a reference with a tight temperature coefficient
specification to reduce the dependence of the DAC output voltage on ambient conditions. In high-accuracy
applications, which have a relatively low noise budget, the reference output voltage noise also must be
considered. Choosing a reference with as low an output noise voltage as practical for the required system
resolution is important. Precision voltage references such as TI's REF50xx (2V to 5V) and REF32xx (1.25V to
4V) provide a low-drift, high-accuracy reference voltage.
POWER-SUPPLY NOISE
The DAC7718 must have ample supply bypassing of 1mF to 10mF in parallel with 0.1mF on each supply, located
as close to the package as possible; ideally, immediately next to the device. The 1mF to 10mF capacitors must be
the tantalum-bead type. The 0.1mF capacitor must have low effective series resistance (ESR) and low effective
series inductance (ESI), such as common ceramic types, which provide a low-impedance path to ground at high
frequencies to handle transient currents because of internal logic switching. The power-supply lines must be as
large a trace as possible to provide low-impedance paths and reduce the effects of glitches on the power-supply
line. Apart from these considerations, the wideband noise on the AVDD, AVSS, DVDD and IOVDD supplies should
be filtered before feeding to the DAC to obtain the best possible noise performance.
LAYOUT
Precision analog circuits require careful layout, adequate bypassing, and a clean, well-regulated power supply to
obtain the best possible dc and ac performance. Careful consideration of the power-supply and ground-return
layout helps to meet the rated performance. DGND is the return path for digital currents and AGND is the power
ground for the DAC. For the best ac performance, care should be taken to connect DGND and AGND with very
low resistance back to the supply ground. The PCB must be designed so that the analog and digital sections are
separated and confined to certain areas of the board. If multiple devices require an AGND-to-DGND connection,
the connection is to be made at one point only. The star ground point is established as close as possible to the
device.
The power-supply traces must be as large as possible to provide low impedance paths and reduce the effects of
glitches on the power-supply line. Fast switching signals must never be run near the reference inputs. It is
essential to minimize noise on the reference inputs because it couples through to the DAC output. Avoid
crossover of digital and analog signals. Traces on opposite sides of the board must run at right angles to each
other. This configuration reduces the effects of feedthrough on the board. A microstrip technique may be
considered, but is not always possible with a double-sided board. In this technique, the component side of the
board is dedicated to the ground plane, and signal traces are placed on the solder-side.
Each DAC group has a ground pin, AGND-x, which is the ground of the output from the DACs in the group. It
must be connected directly to the corresponding reference ground in low-impedance paths to get the best
performance. AGND-A must be connected with REFGND-A and AGND-B must be connected with REFGND-B.
AGND-A and AGND-B must be tied together and connected to the analog power ground and DGND.
During single-supply operation, the OFFSET-x pins must be connected to AGND-x with a low-impedance path
because these pins carry DAC-code-dependent current. Any resistance from OFFSET-x to AGND-x causes a
voltage drop by this code-dependent current. Therefore, it is very important to minimize routing resistance to
AGND-x or to any ground plane that AGND-x is connected to.
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
DAC7718SPAG
ACTIVE
TQFP
PAG
64
160
RoHS & Green
NIPDAU
Level-4-260C-72 HR
-40 to 85
DAC7718S
DAC7718SPAGR
ACTIVE
TQFP
PAG
64
1500
RoHS & Green
NIPDAU
Level-4-260C-72 HR
-40 to 85
DAC7718S
DAC7718SRGZR
ACTIVE
VQFN
RGZ
48
2500
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-40 to 85
DAC7718S
DAC7718SRGZT
ACTIVE
VQFN
RGZ
48
250
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-40 to 85
DAC7718S
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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