AD7237AAR ,LC2MOS Dual 12-Bit DACPORTsFEATURESComplete Dual 12-Bit DAC ComprisingTwo 12-Bit CMOS DACsOn-Chip Voltage ReferenceOutput Ampl ..
AD7237ABN ,LC2MOS Dual 12-Bit DACPORTsSPECIFICATIONS DGND = 0 V [AD7237A], GND = 0 V [AD7247A], REF IN = +5 V,R = 2 kΩ, C = 100 pF. All
AD7237ABR ,LC2MOS Dual 12-Bit DACPORTsSpecifications subject to change without notice.–2– REV. 0AD7237A/AD7247A3 3(V = +12 V to +15 V, V ..
AD7237KN ,LC2MOS DUAL 12-BIT DACPORT
AD7237KN ,LC2MOS DUAL 12-BIT DACPORT
AD7242JN ,LC2MOS Dual, Complete, 12-Bit/14-Bit Serial DACsSpecifications subject to change without notice.AD7242 ORDERING GUIDETemperature Integral PackageMo ..
ADCMP582BCPZ-RL7 , Ultrafast SiGe Voltage Comparators
ADCMP600BKSZ-REEL7 , Rail-to-Rail, Very Fast, 2.5 V to 5.5 V, Single-Supply TTL/CMOS Comparators
ADCMP600BRJZ-REEL7 , Rail-to-Rail, Very Fast, 2.5 V to 5.5 V, Single-Supply TTL/CMOS Comparators
ADCMP600BRJZ-REEL7 , Rail-to-Rail, Very Fast, 2.5 V to 5.5 V, Single-Supply TTL/CMOS Comparators
ADCMP601BKSZ-REEL7 , Rail-to-Rail, Very Fast, 2.5 V to 5.5 V, Single-Supply TTL/CMOS Comparators
ADCMP604BKSZ-REEL7 , Rail-to-Rail, Very Fast, 2.5 V to 5.5 V, Single-Supply LVDS Comparators
AD7237AAN-AD7237AAR-AD7237ABN-AD7237ABR-AD7247AAN-AD7247AAR-AD7247ABN-AD7247ABR-AD7247ATQ
LC2MOS Dual 12-Bit DACPORTs
FUNCTIONAL BLOCK DIAGRAMSREV.0
LC2MOS
Dual 12-Bit DACPORTs
FEATURES
Complete Dual 12-Bit DAC Comprising
Two 12-Bit CMOS DACs
On-Chip Voltage Reference
Output Amplifiers
Reference Buffer Amplifiers
Improved AD7237/AD7247:
12 V to 15 V Operation
Faster Interface –30 ns typ Data Setup Time
Parallel Loading Structure: AD7247A
(8+4) Loading Structure: AD7237A
Single or Dual Supply Operation
Low Power—165 mW typ in Single Supply
PRODUCT HIGHLIGHTSThe AD7237A/AD7247A is a dual 12-bit DACPORT® on a
single chip. This single chip design and small package size
offer considerable space saving and increased reliability over
multichip designs.The improved interface times of the parts allow easy, direct
interfacing to most modern microprocessors, whether they
have 8-bit or 16-bit data bus structures.The AD7237A/AD7247A features a wide power supply
range allowing operation from 12 V supplies.
DACPORT is a registered trademark of Analog Devices, Inc.
GENERAL DESCRIPTIONThe AD7237A/AD7247A is an enhanced version of the industry
standard AD7237/AD7247. Improvements include operation
from 12 V to 15 V supplies, faster interface times and better
reference variations with VDD. Additional features include faster
settling times.
The AD7237A/AD7247A is a complete, dual, 12-bit, voltage
output digital-to-analog converter with output amplifiers and
Zener voltage reference on a monolithic CMOS chip. No exter-
nal user trims are required to achieve full specified performance.
Both parts are microprocessor compatible, with high speed data
latches and interface logic. The AD7247A accepts 12-bit paral-
lel data which is loaded into the respective DAC latch using the
WR input and a separate Chip Select input for each DAC. The
AD7237A has a double buffered interface structure and an 8-bit
wide data bus with data loaded to the respective input latch in
two write operations. An asynchronous LDAC signal on the
AD7237A updates the DAC latches and analog outputs.
A REF OUT/REF IN function is provided which allows either
the on-chip 5 V reference or an external reference to be used as
a reference voltage for the part. For single supply operation, two
output ranges of 0 V to +5 V and 0 V to +10 V are available,
while these two ranges plus an additional ±5 V range are avail-
able with dual supplies. The output amplifiers are capable of de-
veloping +10 V across a 2 kΩ load to GND.
The AD7237A/AD7247A is fabricated in Linear Compatible
CMOS (LC2MOS), an advanced, mixed technology process
that combines precision bipolar circuits with low power CMOS
logic. Both parts are available in a 24-pin, 0.3" wide plastic and
hermetic dual-in-line package (DIP) and are also packaged in a
24-lead small outline (SOIC) package.
AD7237A/AD7247A–SPECIFICATIONS
(VDD = +12 V to +15 V,1 VSS = 0 V or –12 V to –15 V,1 AGND =
DGND = 0 V [AD7237A], GND = 0 V [AD7247A], REF IN = +5 V,STATIC PERFORMANCE
REFERENCE INPUT
ANALOG OUTPUTS
POWER REQUIREMENTS
NOTESPower Supply tolerance is ±10% for A version and ±5% for B and T versions.Temperature ranges are as follows: A, B Versions, –40°C to +85°C; T Version, –55°C to +125°C.See Terminology.With appropriate power supply tolerances.Measured with respect to REF IN and includes unipolar/bipolar offset error.Sample tested @ +25°C to ensure compliance.0 V to +10 V range is only available with VDD ≥ 14.25 V.
Specifications subject to change without notice.
RL = 2 kΩ, CL = 100 pF. All specifications TMIN to TMAX unless otherwise noted.)
TIMING CHARACTERISTICS1, 2NOTESSample tested at +25°C to ensure compliance. All input signals are specified with tr = tf = 5 ns (10% to 90% of 5 V) and timed from a voltage level of 1.6 V.See Figures 5 and 7.Power Supply tolerance is ±10% for A version and ±5% for B and T versions.If 0 ns < t2 < 10 ns, add t2 to t5. If t2 ≥ 10 ns, add 10 ns to t5.AD7237A only.
ABSOLUTE MAXIMUM RATINGS1(TA = +25°C unless otherwise noted)
VDD to GND (AD7247A) . . . . . . . . . . . . . . . .–0.3 V to +17 V
VDD to AGND, DGND (AD7237A) . . . . . . . .–0.3 V to +17 V
VDD to VSS . . . . . . . . . . . . . . . . . . . . . . . . . . . .–0.3 V to +34 V
AGND to DGND (AD7237A) . . . . . . . . .–0.3 V, VDD +0.3 V
VOUTA,2 VOUTB2 to AGND (GND) . .VSS –0.3 V to VDD +0.3 V
REF OUT to AGND (GND) . . . . . . . . . . . . . . . . .0 V to VDD
REF IN to AGND (GND) . . . . . . . . . .–0.3 V to VDD +0.3 V
Digital Inputs to DGND (GND) . . . . . .–0.3 V to VDD +0.3 V
Operating Temperature Range
Industrial (A, B Versions) . . . . . . . . . . . . .–40°C to +85°C
Extended (T Version) . . . . . . . . . . . . . . .–55°C to +125°C
Storage Temperature Range . . . . . . . . . . . .–65°C to +150°C
Lead Temperature (Soldering, 10 secs) . . . . . . . . . . . .+300°C
Power Dissipation (Any Package) to +75°C . . . . . . .1000 mW
Derates above +75°C by . . . . . . . . . . . . . . . . . . . . .10 mW/°C
NOTESStresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those listed in the
operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.Short-circuit current is typically 80 mA. The outputs may be shorted to voltages
in this range provided the power dissipation of the package is not exceeded.
ORDERING GUIDENOTESTo order MIL-STD-883, Class B processed parts, add /883B to part number.
Contact local sales office for military data sheet and availability.N = Plastic DIP; Q = Cerdip; R = Small Outline (SOIC).
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD7237A/AD7247A features proprietary ESD protection circuitry, permanent
damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper
ESD precautions are recommended to avoid performance degradation or loss of functionality.
(VDD = +12 V to +15 V,3 VSS = 0 V or –12 V to –15 V,3 AGND = DGND = 0 V [AD7237A],
GND = 0 V [AD7247A])
AD7237A/AD7247A
AD7237A PIN FUNCTION DESCRIPTION (DIP PIN NUMBERS)8-10
AD7247A PIN FUNCTION DESCRIPTION (DIP PIN NUMBERS)
AD7237A PIN CONFIGURATION
DIP and SOIC
AD7247A PIN CONFIGURATION
DIP and SOIC
AD7237A/AD7247A
TERMINOLOGY
RELATIVE ACCURACY (LINEARITY)Relative Accuracy, or endpoint linearity, is a measure of the
maximum deviation of the DAC transfer function from a
straight line passing through the endpoints of the transfer func-
tion. It is measured after allowing for zero and full-scale errors
and is expressed in LSBs or as a percentage of full-scale reading.
DIFFERENTIAL NONLINEARITYDifferential Nonlinearity is the difference between the measured
change and the ideal 1 LSB change between any two adjacent
codes. A specified differential nonlinearity of ±1 LSB or less
over the operating temperature range ensures monotonicity.
SINGLE SUPPLY LINEARITY AND GAIN ERRORThe output amplifiers of the AD7237A/AD7247A can have true
negative offsets even when the part is operated from a single
+12 V to +15 V supply. However, because the negative supply
rail (VSS) is 0 V, the output cannot actually go negative. Instead,
when the output offset voltage is negative, the output voltage
sits at 0 V, resulting in the transfer function shown in Figure 1.
This “knee” is an offset effect, not a linearity error, and the
transfer function would have followed the dotted line if the out-
put voltage could have gone negative.
Figure 1.Effect of Negative Offset (Single Supply)
Normally, linearity is measured between zero (all 0s input code)
and full scale (all 1s input code) after offset and full scale have
been adjusted out or allowed for, but this is not possible in
single supply operation if the offset is negative, due to the knee
in the transfer function. Instead, linearity of the AD7237A/
AD7247A in the unipolar mode is measured between full scale
and the lowest code which is guaranteed to produce a positive
output voltage. This code is calculated from the maximum
specification for negative offset, i.e., linearity is measured be-
tween Codes 3 and 4095.
UNIPOLAR OFFSET ERRORUnipolar Offset Error is the measured output voltage from
VOUTA or VOUTB with all zeros loaded into the DAC latches
when the DACs are configured for unipolar output. It is a com-
bination of the offset errors of the DAC and output amplifier.
BIPOLAR ZERO ERRORBipolar Zero Error is the voltage measured at VOUTA or VOUTB
when the DAC is connected in the bipolar mode and loaded
with code 2048. It is due to a combination of offset errors in the
DAC, amplifier offset and mismatch in the application resistors
around the amplifier.
FULL-SCALE ERRORFull-Scale Error is a measure of the output error when the
amplifier output is at full scale (for the bipolar output range full
scale is either positive or negative full scale). It is measured with
respect to the reference input voltage and includes the offset
errors.
DIGITAL FEEDTHROUGHDigital Feedthrough is the glitch impulse injected for the digital
inputs to the analog output when the data inputs change state,
but the data in the DAC latches is not changed.
For the AD7237A it is measured with LDAC held high. For the
AD7247A it is measured with CSA and CSB held high.
DIGITAL CROSSTALKDigital crosstalk is the glitch impulse transferred to the output
of one converter due to a change in digital code to the DAC
latch of the other converter. It is specified in nV secs.
DIGITAL-TO-ANALOG GLITCH IMPULSEThis is the voltage spike that appears at the output of the DAC
when the digital code changes before the output settles to its fi-
nal value. The energy in the glitch is specified in nV secs and is
measured for a 1 LSB change around the major carry transition
(0111 1111 1111 to 1000 0000 0000).
