Analog Devices AD644 Datasheet
OUTPUT
NONINVERTING
INPUT
OUTPUT
INVERTING
INPUT
INVERTING
INPUT
NONINVERTING
INPUT
–V
3
4
5
6
7
8
1
2
+V
TOP
VIEW
NOTE:
PIN 4 CONNECTED TO CASE
AMPLIFIER NO. 1 AMPLIFIER NO. 2
Dual High Speed,
a
FEATURES
Matched Offset Voltage
Matched Offset Voltage Over Temperature
Matched Bias Currents
Crosstalk –124 dB at 1 kHz
Low Bias Current: 35 pA max Warmed Up
Low Offset Voltage: 500 mV max
Low Input Voltage Noise: 2 mV p-p
High Slew Rate: 13 V/ms
Low Quiescent Current: 4.5 mA max
Fast Settling to 60.01%: 3 ms
Low Total Harmonic Distortion: 0.0015% at 1 kHz
Standard Dual Amplifier Pinout
Available in Hermetic Metal Can Package
and Chip Form
MIL-STD-883B Processing Available
Single Version Available: AD544
PRODUCT DESCRIPTION
The AD644 is a pair of matched high speed monolithic FET input operational amplifiers fabricated with the most advanced bipolar, JFET and laser-trimming technologies. The AD644 offers
matched bias currents that are significantly lower than currently
available monolithic dual BiFET operational amplifiers: 35 pA
max, matched to 25 pA for the AD644K and L, 75 pA max
matched to 35 pA for the AD644J and S. In addition, the offset
voltage is laser trimmed to less than 0.5 mV, and matched to
0.25 mV for the AD644L, 1.0 mV and matched to 0.5 mV for
the AD644K, utilizing Analog Devices’ laser-wafer trimming
(LWT) process.
The tight matching and temperature tracking between the operational amplifiers is achieved by ion-implanted JFETs and
laser-wafer trimming. Ion-implantation permits the fabrication
of precision, matched JFETs on a monolithic bipolar chip. This
process optimizes the ability to produce matched amplifiers
which have lower initial bias currents than other popular BiFET
op amps. Laser-wafer trimming each amplifier’s input offset
voltage assures tight initial match and superior IC processing
guarantees offset voltage tracking over the temperature range.
The AD644 is recommended for applications in which both
excellent ac and dc performance is required. The matched amplifiers provide a low cost solution to true wideband instrumentation amplifiers, low dc drift active filters and output amplifiers
for four quadrant multiplying D/A converters such as the
AD7541, 12-bit CMOS DAC.
The AD644 is available in four versions: the “J”, “K” and “L”
are specified over the 0°C to +70°C temperature range and the
“S” over the –55°C to +125°C operating temperature range.
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Implanted BiFET Op Amp
AD644
PIN CONFIGURATION
All devices are packaged in the hermetically sealed, TO-99
metal can or available in chip form.
PRODUCT HIGHLIGHTS
1. The AD644 has tight side to side matching specifications to
ensure high performance without matching individual devices.
2. Analog Devices, unlike some manufacturers, specifies each
device for the maximum bias current at either input in the
warmed-up condition, thus assuring the user that the AD644
will meet its published specifications in actual use.
3. Laser-wafer-trimming reduces offset voltage to as low as
0.5 mV max matched side to side to 0.25 mV (AD644L),
thus eliminating the need for external nulling.
4. Improved bipolar and JFET processing on the AD644 result
in the lowest matched bias current available in a high speed
monolithic FET op amp.
5. Low voltage noise (2 µV p-p) and high open loop gain
enhance the AD644’s performance as a precision op amp.
6. The high slew rate (13.0 V/µs) and fast settling time to
0.01% (3.0 µs) make the AD644 ideal for D/A, A/D, sample-
hold circuits and dual high speed integrators.
7. Low harmonic distortion (0.0015%) and low crosstalk
(–124 dB) make the AD644 an ideal choice for stereo audio
applications.
8. The standard dual amplifier pin out allows the AD644 to
replace lower performance duals without redesign.
9. The AD644 is available in chip form.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
AD644–SPECIFICA TIONS
(@ +258C and VS = 615 V dc)
Model AD644J AD644K AD644L AD644S
Min Typ Max Min Typ Max Min Typ Max Min Typ Max Units
OPEN LOOP GAIN
VO = ± 10 V, RL ≥ 2 kΩ 30,000 50,000 50,000 50,000 V/V
T
to T
MIN
, RL = 2 kΩ 20,000 40,000 40,000 20,000 V/V
MAX
OUTPUT CHARACTERISTICS
Voltage @ R
Voltage @ R
Short Circuit Current 25 25 25 25 mA
= 2 kΩ, T
L
= 10 kΩ, T
L
MIN
MIN
to T
to T
610 ±12 610 ±12 610 ±12 610 ±12 V
MAX
612 ±13 612 ±13 612 ±13 612 ±13 V
MAX
FREQUENCY RESPONSE
Unity Gain Small Signal 2.0 2.0 2.0 2.0 MHz
Full Power Response 200 200 200 200 kHz
Slew Rate, Unity Gain 8.0 13.0 8.0 13.0 8.0 13.0 8.0 13.0 V/µs
Total Harmonic Distortion 0.0015 0.0015 0.0015 0.0015 %
INPUT OFFSET VOLTAGE
1
Initial Offset 2.0 1.0 0.5 1.0 mV
Input Offset Voltage T
Input Offset Voltage vs. Supply,
T
to T
MIN
MAX
INPUT BIAS CURRENT
MIN
2
to T
MAX
3.5 2.0 1.0 3.5 mV
200 100 100 100 µV/V
Either Input 10 75 10 35 10 35 10 35 pA
Offset Current 10 5 5 5 pA
MATCHING CHARACTERISTICS
3
Input Offset Voltage 1.0 0.5 0.25 0.5 mV
Input Offset Voltage T
Input Bias Current 35 25 25 35 pA
MIN
to T
MAX
3.5 2.0 1.0 3.5 mV
Crosstalk –124 –124 –124 –124 dB
INPUT IMPEDANCE
Differential 10
Common Mode 1012i310
INPUT VOLTAGE RANGE
Differential
4
12
i610
12
i610
12
i310
12
i610
12
i310
12
i6MΩipF
12
i3MΩipF
±20 ±20 ±20 ±20 V
Common Mode ± 10 ±12 ± 10 ±12 ±10 ±12 ± 10 ± 12 V
Common-Mode Rejection 76 80 80 80 dB
INPUT NOISE
Voltage 0.1 Hz to 10 Hz 2222µV p-p
f = 10 Hz 35 35 35 35 nV/√
f = 100 Hz 22 22 22 22 nV/√
f = 1 kHz 18 18 18 18 nV/√
Hz
Hz
Hz
f = 10 kHz 16 16 16 16 nV/√Hz
POWER SUPPLY
Rated Performance ± 15 ±15 ± 15 ±15 V
Operating ± 5 ±18 ±5 ±18 ±5 ± 18 ± 5 ±18 V
Quiescent Current 3.5 4.5 3.5 4.5 3.5 4.5 3.5 4.5 mA
TEMPERATURE RANGE
Operating, Rated Performance 0 +70 0 +70 0 +70 –55 +125 °C
Storage –65 +150 –65 +150 –65 +150 –65 +150 °C
PACKAGE OPTION
TO-99 Style (H-08B) AD644JH AD644KH AD644LH AD644SH
Chips AD644JChips AD644KChips AD644SChips
NOTES
1
Input Offset Voltage specifications are guaranteed after 5 minutes of operation at TA = +25°C.
2
Bias Current specifications are guaranteed at maximum at either input after 5 minutes of operation at TA = +25°C. For higher temperatures, the current doubles every 10°C.
3
Matching is defined as the difference between parameters of the two amplifiers.
4
Defined as voltage between inputs, such that neither exceeds ±10 V from ground.
Specifications shown in boldface are tested on all production units at final electrical test. Results from those tests are used to calculate outgoing quality levels. All min and max specifications
are guaranteed, although only those shown in boldface are tested on all production units.
Specifications subject to change without notice.
METALIZATION PHOTOGRAPH
Dimensions shown in inches and (mm).
Contact factory for latest dimensions.
–2–
REV. A
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