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FEATURES
Wide Bandwidth: 60 MHz at Gain of –1
Wide Bandwidth: 33 MHz at Gain of –10
Very High Output Slew Rate: Up to 2000 V/s
20 MHz Full Power Bandwidth, 20 V pk-pk, RL = 500 ⍀
Fast Settling: 100 ns to 0.1% (10 V Step)
Differential Gain Error: 0.03% at 4.4 MHz
Differential Phase Error: 0.15؇ at 4.4 MHz
High Output Drive: ؎50 mA into 50 Ω Load
Low Offset Voltage: 150 V max (B Grade)
Low Quiescent Current: 6.5 mA
Available in Tape and Reel in Accordance with
EIA-481A Standard
60 MHz, 2000 V/s
Monolithic Op Amp
AD844
CONNECTION DIAGRAMS
8-Pin Plastic (N),
and Cerdip (Q) Packages
16-Pin SOIC
(R) Package
APPLICATIONS
Flash ADC Input Amplifiers
High Speed Current DAC Interfaces
Video Buffers and Cable Drivers
Pulse Amplifiers
PRODUCT DESCRIPTION
The AD844 is a high speed monolithic operational amplifier fabricated using Analog Devices’ junction isolated complementary
bipolar (CB) process. It combines high bandwidth and very fast
large signal response with excellent dc performance. Although
optimized for use in current to voltage applications and as an
inverting mode amplifier, it is also suitable for use in many noninverting applications.
The AD844 can be used in place of traditional op amps, but its
current feedback architecture results in much better ac performance, high linearity and an exceptionally clean pulse response.
This type of op amp provides a closed-loop bandwidth which is
determined primarily by the feedback resistor and is almost independent of the closed-loop gain. The AD844 is free from the
slew rate limitations inherent in traditional op amps and other
current-feedback op amps. Peak output rate of change can be
over 2000 V/µs for a full 20 V output step. Settling time is typically 100 ns to 0.1%, and essentially independent of gain. The
AD844 can drive 50 Ω loads to ± 2.5 V with low distortion and
is short circuit protected to 80 mA.
The AD844 is available in four performance grades and three
package options. In the 16-pin SOIC (R) package, the AD844J
is specified for the commercial temperature range of 0°C to
+70°C. The AD844A and AD844B are specified for the industrial temperature range of –40°C to +85°C and are available in
the cerdip (Q) package. The AD844A is also available in an 8-pin
plastic mini-DIP (N). The AD844S is specified over the military
temperature range of –55°C to +125°C. It is available in the
8-pin cerdip (Q) package. “A” and “S” grade chips and devices
processed to MIL-STD-883B, REV. C are also available.
PRODUCT HIGHLIGHTS
1. The AD844 is a versatile, low cost component providing an
excellent combination of ac and dc performance. It may be
used as an alternative to the EL2020 and CLC400/1.
2. It is essentially free from slew rate limitations. Rise and fall
times are essentially independent of output level.
3. The AD844 can be operated from ± 4.5 V to ± 18 V power
supplies and is capable of driving loads down to 50 Ω, as
well as driving very large capacitive loads using an external
network.
4. The offset voltage and input bias currents of the AD844 are
laser trimmed to minimize dc errors; VOS drift is typically
1 µV/°C and bias current drift is typically 9 nA/°C.
5. The AD844 exhibits excellent differential gain and differential phase characteristics, making it suitable for a variety of
video applications with bandwidths up to 60 MHz.
6. The AD844 combines low distortion, low noise and low drift
with wide bandwidth, making it outstanding as an input amplifier for flash A/D converters.
REV. C
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.
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Tel: 617/329-4700
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