60 MHz 2000 V/μs
Monolithic Op Amp
AD844
Rev. F
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FEATURES
Wide bandwidth
60 MHz at gain of −1
33 MHz at gain of −10
Slew rate: 2000 V/μs
20 MHz full power bandwidth, 20 V p-p, R
L
= 500 Ω
Fast settling: 100 ns to 0.1% (10 V step)
Differential gain error: 0.03% at 4.4 MHz
Differential phase error: 0.16° at 4.4 MHz
Low offset voltage: 150 μV maximum (B Grade)
Low quiescent current: 6.5 mA
Available in tape and reel in accordance with
EIA-481-A standard
APPLICATIONS
Flash ADC input amplifiers
High speed current DAC interfaces
Video buffers and cable drivers
Pulse amplifiers
FUNCTIONAL BLOCK DIAGRAMS
NULL
1
–IN
2
+IN
3
–V
S
4
NULL
8
+V
S
7
OUTPUT
6
TZ
5
AD844
TOP VIEW
(Not to Scale)
00897-001
Figure 1. 8-Lead PDIP (N) and 8-Lead CERDIP (Q) Packages
NC
OFFSETNULL
–IN
NC
+IN
NC
V–
NC
NC
OFFSETNULL
V+
NC
OUTPUT
TZ
NC
NC
1
2
3
4
16
15
14
13
5 12
6 11
7 10
8 9
NC = NO CONNECT
AD844
TOP VIEW
(Not to Scale)
00897-002
Figure 2. 16-Lead SOIC (R) Package
GENERAL DESCRIPTION
The AD844 is a high speed monolithic operational amplifier
fabricated using the Analog Devices, Inc., junction isolated
complementary bipolar (CB) process. It combines high band-
width 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 perfor-
mance, high linearity, and an exceptionally clean pulse response.
This type of op amp provides a closed-loop bandwidth that 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-lead SOIC (RW) 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-lead
PDIP (N). The AD844S is specified over the military temperature
range of −55°C to +125°C. It is available in the 8-lead 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.
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; V
OS
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 analog-to-digital converters (ADCs).
