AD712SQ ,Dual Precision, Low Cost, High Speed, BiFET Op Ampapplications such as DAC and ADC buffers which re-The AD712 is pinned out in a standard op amp conf ..
AD712SQ/883B ,Dual Precision, Low Cost, High Speed, BiFET Op AmpCHARACTERISTICSVoltage +13, –12.5 +13.9, –13.3 +13, –12.5 +13.9, –13.3 +13, –12.5 +13.9, –13.3 V±12 ..
AD712TQ ,Dual Precision, Low Cost, High Speed, BiFET Op Ampapplications such as DAC and ADC buffers which re-The AD712 is pinned out in a standard op amp conf ..
AD712TQ/883B ,Dual Precision, Low Cost, High Speed, BiFET Op AmpCHARACTERISTICSVoltage +13, –12.5 +13.9, –13.3 +13, –12.5 +13.9, –13.3 +13, –12.5 +13.9, –13.3 V±12 ..
AD712TQ883B ,Dual Precision, Low Cost, High Speed, BiFET Op Ampapplications. With a slew rate of 16 V/μsand a settling time of 1 μs to ±0.01%, the AD712 is ideal ..
AD713AQ ,Quad Precision, Low Cost, High Speed, BiFET Op AmpSpecifications subject to change without notice.–2– REV. BAD7131, 2ABSOLUTE MAXIMUM RATINGS ORDERIN ..
ADC71JG ,Brown Corporation - 16-Bit ANALOG-TO-DIGITAL CONVERTER
ADC71KG ,Brown Corporation - 16-Bit ANALOG-TO-DIGITAL CONVERTER
ADC71KG ,Brown Corporation - 16-Bit ANALOG-TO-DIGITAL CONVERTER
ADC7802BN ,Brown Corporation - Autocalibrating, 4-Channel, 12-Bit ANALOG-TO-DIGITAL CONVERTER
ADC78H89CIMT ,7-Channel, 500 KSPS, 12-Bit A/D Converter
ADC78H89CIMT ,7-Channel, 500 KSPS, 12-Bit A/D Converter
AD712AH-AD712AQ-AD712BQ-AD712CH-AD712JN-AD712JN.-AD712JR-AD712JR-REEL-AD712JR-REEL7-AD712JR--REEL7-AD712KN-AD712KR-AD712SQ-AD712SQ/883B-AD712TQ-AD712TQ/883B-AD712TQ883B
Dual Precision, Low Cost, High Speed, BiFET Op Amp
REV.B
CONNECTION DIAGRAMS
TO-99
(H) Package
OUTPUT
INVERTING
OUTPUT
NONINVERTING
OUTPUT
OUTPUT
INVERTING
INPUT
NONINVERTING
INPUT
–VS
+VSAMPLIFIER NO. 2AMPLIFIER NO. 1
AD712
Plastic Mini-DIP (N) Package
SOIC (R) Package and Cerdip (Q) Package
OUTPUT
INVERTING
OUTPUT
NONINVERTING
OUTPUT
OUTPUT
INVERTING
INPUT
NONINVERTING
INPUTV–
AMPLIFIER NO. 2AMPLIFIER NO. 1
FEATURES
Enhanced Replacements for LF412 and TL082
AC PERFORMANCE
Settles to 60.01% in 1.0 ms
16 V/ms min Slew Rate (AD712J)
3 MHz min Unity Gain Bandwidth (AD712J)
DC PERFORMANCE
0.30 mV max Offset Voltage: (AD712C)
5 mV/8C max Drift: (AD712C)
200 V/mV min Open-Loop Gain (AD712K)
4 mV p-p max Noise, 0.1 Hz to 10 Hz (AD712C)
Surface Mount Available in Tape and Reel in Accor-
dance with EIA-481A Standard
MIL-STD-883B Parts Available
Single Version Available: AD711
Quad Version: AD713
Available in Plastic Mini-DIP, Plastic SOIC, Hermetic
Cerdip, Hermetic Metal Can Packages and Chip Form
Dual Precision, Low Cost,
High Speed, BiFET Op Amp
PRODUCT DESCRIPTIONThe AD712 is a high speed, precision monolithic operational
amplifier offering high performance at very modest prices. Its
very low offset voltage and offset voltage drift are the results of
advanced laser wafer trimming technology. These performance
benefits allow the user to easily upgrade existing designs that use
older precision BiFETs and, in many cases, bipolar op amps.
The superior ac and dc performance of this op amp makes it
suitable for active filter applications. With a slew rate of 16 V/μs
and a settling time of 1 μs to ±0.01%, the AD712 is ideal as a
buffer for 12-bit D/A and A/D Converters and as a high-speed
integrator. The settling time is unmatched by any similar IC
amplifier.
The combination of excellent noise performance and low input
current also make the AD712 useful for photo diode preamps.
Common-mode rejection of 88 dB and open loop gain of
400 V/mV ensure 12-bit performance even in high-speed unity
gain buffer circuits.
The AD712 is pinned out in a standard op amp configuration
and is available in seven performance grades. The AD712J and
AD712K are rated over the commercial temperature range of
0°C to +70°C. The AD712A, AD712B and AD712C are rated
over the industrial temperature range of –40°C to +85°C. The
AD712S and AD712T are rated over the military temperature
range of –55°C to +125°C and are available processed to MIL-
STD-883-B, Rev. C.
Extended reliability PLUS screening is available, specified over
the commercial and industrial temperature ranges. PLUS
screening includes 168-hour burn-in, as well as other environ-
mental and physical tests.
The AD712 is available in an 8-lead plastic mini-DIP, SOIC,
cerdip, TO-99 metal can, or in chip form.
PRODUCT HIGHLIGHTSThe AD712 offers excellent overall performance at very
competitive prices.Analog Devices’ advanced processing technology and with
100% testing guarantees a low input offset voltage (0.3 mV
max, C grade, 3 mV max, J grade). Input offset voltage is
specified in the warmed-up condition. Analog Devices’ laser
wafer drift trimming process reduces input offset voltage
drifts to 5 μV/°C max on the AD712C.Along with precision dc performance, the AD712 offers
excellent dynamic response. It settles to ±0.01% in 1 μs and
has a minimum slew rate of 16 V/μs. Thus this device is ideal
for applications such as DAC and ADC buffers which re-
quire a combination of superior ac and dc performance.The AD712 has a guaranteed and tested maximum voltage
noise of 4 μV p-p, 0.1 Hz to 10 Hz (AD712C).Analog Devices’ well-matched, ion-implanted JFETs ensure
a guaranteed input bias current (at either input) of 50 pA
max (AD712C) and an input offset current of 10 pA max
(AD712C). Both input bias current and input offset current
are guaranteed in the warmed-up condition.
NOTES
1Input Offset Voltage specifications are guaranteed after 5 minutes of operation at TA = +25°C.Bias Current specifications are guaranteed maximum at either input after 5 minutes of operation at TA = +25°C. For higher temperatures, the current doubles every 10°C.
AD712–SPECIFICATIONS
(VS = 615 V @ TA = +258C unless otherwise noted)
ABSOLUTE MAXIMUM RATINGS1Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .±18 V
Internal Power Dissipation2
Input Voltage3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .±18 V
Output Short Circuit Duration . . . . . . . . . . . . . . . . .Indefinite
Differential Input Voltage . . . . . . . . . . . . . . . . . .+VS and –VS
Storage Temperature Range (Q, H) . . . . . . .–65°C to +150°C
Storage Temperature Range (N, R) . . . . . . . .–65°C to +125°C
Operating Temperature Range
AD712J/K . . . . . . . . . . . . . . . . . . . . . . . . . . .0°C to +70°C
AD712A/B/C . . . . . . . . . . . . . . . . . . . . . . . .–40°C to +85°C
AD712S/T . . . . . . . . . . . . . . . . . . . . . . . . .–55°C to +125°C
Lead Temperature Range (Soldering 60 sec) . . . . . . . .+300°C
NOTESStresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.Thermal Characteristics:
8-Lead Plastic Package:θJA = 165°C/Watt
8-Lead Cerdip Package:θJC = 22°C/Watt; θJA = 110°C/Watt
8-Lead Metal Can Package:θJC = 65°C/Watt; θJA = 150°C/Watt
8-Lead SOIC Package:θJA = 100°CFor supply voltages less than ±18 V, the absolute maximum input voltage is equal
to the supply voltage.
ORDERING GUIDE
METALIZATION PHOTOGRAPHDimensions shown in inches and (mm).
Contact factory for latest dimensions.
AD712
SUPPLY VOLTAGE 6 Volts
INPUT VOLTAGE SWING – Volts05201015Figure 1.Input Voltage Swing vs.
Supply Voltage
SUPPLY VOLTAGE 6 Volts
QUIESCENT CURRENT – mA5201015Figure 4.Quiescent Current vs.
Supply Voltage
COMMON MODE VOLTAGE – Volts
INPUT BIAS CURRENT – pA
–10Figure 7.Input Bias Current vs.
Common Mode Voltage
–Typical Performance Characteristics
SUPPLY VOLTAGE 6 Volts
OUTPUT VOLTAGE SWING – Volts05201015Figure 2.Output Voltage Swing vs.
Supply Voltage
TEMPERATURE – 8C
INPUT BIAS CURRENT (V
= 0) – Amps12
10109876Figure 5.Input Bias Current vs.
Temperature
AMBIENT TEMPERATURE – 8C
SHORT CIRCUIT CURRENT LIMIT – mA
–40–20020406080100120140Figure 8.Short Circuit Current
Limit vs. Temperature
LOAD RESISTANCE – V
OUTPUT VOLTAGE SWING – Volts p–p1010010k1kFigure 3.Output Voltage Swing
vs. Load Resistance
FREQUENCY – Hz
OUTPUT IMPEDANCE –
0.011k
10k100k1M10MFigure 6.Output Impedance vs.
Frequency
TEMPERATURE – 8C
UNITY GAIN BANDWIDTH – MHz
5.0Figure 9.Unity Gain Bandwidth vs.
Temperature
Figure 10.Open-Loop Gain and
Phase Margin vs. Frequency
FREQUENCY – Hz
CMR – dB10
1001k10k100k1MFigure 13.Common Mode Rejec-
tion vs. Frequency
FREQUENCY – Hz
THD – dB
10010k1k
100kFigure 16.Total Harmonic Distor-
tion vs. Frequency
SUPPLY VOLTAGE 6 Volts
OPEN LOOP GAIN – dB
100Figure 11.Open-Loop Gain vs.
Supply Voltage
Figure 14.Large Signal Frequency
Response
Figure 17.Input Noise Voltage
Spectral Density
SUPPLY MODULATION FREQUENCY – Hz
POWER SUPPLY REJECTION – dB
1001k10k100k1MFigure 12.Power Supply Rejection
vs. Frequency
Figure 15.Output Swing and Error
vs. Settling Time
Figure 18.Slew Rate vs. Input
Error Signal
AD712
TEMPERATURE – 8C
SLEW RATE – V/Figure 19.Slew Rate vs. Temperature
Figure 20.T.H.D. Test Circuit
Figure 21.Crosstalk Test Circuit
Figure 22b.Unity Gain Follower
Pulse Response (Large Signal)
Figure 22c.Unity Gain Follower
Pulse Response (Small Signal)
Figure 22a.Unity Gain Follower
–VS
VIN
SQUARE
WAVE
INPUT
5kV
OPTIMIZING SETTLING TIMEMost bipolar high-speed D/A converters have current outputs;
therefore, for most applications, an external op amp is required
for current-to-voltage conversion. The settling time of the con-
verter/op amp combination depends on the settling time of the
DAC and output amplifier. A good approximation is:
The settling time of an op amp DAC buffer will vary with the
noise gain of the circuit, the DAC output capacitance, and with
the amount of external compensation capacitance across the
DAC output scaling resistor.
Settling time for a bipolar DAC is typically 100 ns to 500 ns.
Previously, conventional op amps have required much longer
settling times than have typical state-of-the-art DACs; therefore,
the amplifier settling time has been the major limitation to a
high-speed voltage-output D-to-A function. The introduction of
the AD711/AD712 family of op amps with their 1 μs (to ±0.01%
of final value) settling time now permits the full high-speed
capabilities of most modern DACs to be realized.
In addition to a significant improvement in settling time, the
low offset voltage, low offset voltage drift, and high open-loop
gain of the AD711/AD712 family assures 12-bit accuracy over
the full operating temperature range.
The excellent high-speed performance of the AD712 is shown in
the oscilloscope photos of Figure 25. Measurements were taken
using a low input capacitance amplifier connected directly to the
summing junction of the AD712 – both photos show the worst
case situation: a full-scale input transition. The DAC’s 4 kΩ
[10 kΩ||8 kΩ = 4.4 kΩ] output impedance together with a
10 kΩ feedback resistor produce an op amp noise gain of 3.25.
The current output from the DAC produces a 10 V step at the
op amp output (0 to –10 V Figure 25a, –10 V to 0 V Figure
25b.)
Therefore, with an ideal op amp, settling to ±1/2 LSB (±0.01%)
requires that 375 μV or less appears at the summing junction.
This means that the error between the input and output (that
voltage which appears at the AD712 summing junction) must be
less than 375 μV. As shown in Figure 25, the total settling time
for the AD712/AD565 combination is 1.2 microseconds.
OUTPUT
–10V TO +10V
–15V
0.1mFGAIN
ADJUSTFigure 24.±10 V Voltage Output Bipolar DAC
–10V(Full-Scale Negative Transition)(Full-Scale Positive Transition)
AD712
OP AMP SETTLING TIME -
A MATHEMATICAL MODELThe design of the AD712 gives careful attention to optimizing
individual circuit components; in addition, a careful trade-off
was made: the gain bandwidth product (4 MHz) and slew rate
(20 V/μs) were chosen to be high enough to provide very fast
settling time but not too high to cause a significant reduction in
phase margin (and therefore stability). Thus designed, the
AD712 settles to ±0.01%, with a 10 V output step, in under
1 μs, while retaining the ability to drive a 250 pF load capaci-
tance when operating as a unity gain follower.
If an op amp is modeled as an ideal integrator with a unity gain
crossover frequency of ωο/2π, Equation 1 will accurately de-
scribe the small signal behavior of the circuit of Figure 26a,
consisting of an op amp connected as an I-to-V converter at the
output of a bipolar or CMOS DAC. This equation would com-
pletely describe the output of the system if not for the op amp’s
finite slew rate and other nonlinear effects.
Equation 1.
where
GN = “noise” gain of circuit
This equation may then be solved for Cf:
Equation 2.
In these equations, capacitor CX is the total capacitor appearing
the inverting terminal of the op amp. When modeling a DAC
buffer application, the Norton equivalent circuit of Figure 26a
can be used directly; capacitance CX is the total capacitance of
the output of the DAC plus the input capacitance of the op amp
(since the two are in parallel).
VOUTFigure 26a.Simplified Model of the AD712 Used as a
Current-Out DAC Buffer
When RO and IO are replaced with their Thevenin VIN and RIN
equivalents, the general purpose inverting amplifier of Figure
26b is created. Note that when using this general model, capaci-
tance CX is EITHER the input capacitance of the op amp if a
simple inverting op amp is being simulated OR it is the com-
bined capacitance of the DAC output and the op amp input if
the DAC buffer is being modeled.
VOUT
VINFigure 26b.Simplified Model of the AD712
Used as an Inverter
In either case, the capacitance CX causes the system to go from
a one-pole to a two-pole response; this additional pole increases
settling time by introducing peaking or ringing in the op amp
output. Since the value of CX can be estimated with reasonable
accuracy, Equation 2 can be used to choose a small capacitor,
CF, to cancel the input pole and optimize amplifier response.
Figure 27 is a graphical solution of Equation 2 for the AD712
with R = 4 kΩ.
030405060Figure 27.Value of Capacitor CF vs. Value of CX
