High Speed, Low Noise
Video Op Amp
AD829
Data Sheet
FEATURES
GENERAL DESCRIPTION
The
is a low noise (1.7 nV/√Hz), high speed op amp with
custom compensation that provides the user with gains of 1 to 20
while maintaining a bandwidth >50 MHz. Its 0.04° differential
phase and 0.02% differential gain performance at 3.58 MHz and
4.43 MHz, driving reverse-terminated 50 Ω or 75 Ω cables, makes
it ideally suited for professional video applications. The AD829
achieves its 230 V/µs uncompensated slew rate and 750 MHz
gain bandwidth while requiring only 5 mA of current from
power supplies.
The external compensation pin of the AD829 gives it
exceptional versatility. For example, compensation can be
selected to optimize the bandwidth for a given load and power
supply voltage. As a gain-of-2 line driver, the −3 dB bandwidth
can be increased to 95 MHz at the expense of 1 dB of peaking.
Its output can also be clamped at its external compensation pin.
The AD829 exhibits excellent dc performance. It offers a minimum
open-loop gain of 30 V/mV into loads as low as 500 Ω, a low input
voltage noise of 1.7 nV/√Hz, and a low input offset voltage of 1 mV
maximum. Common-mode rejection and power supply rejection
ratios are both 120 dB.
This op amp is also useful in multichannel, high speed data
conversion where its fast (90 ns to 0.1%) settling time is important.
In such applications, the AD829 serves as an input buffer for 8-bit to
10-bit ADCs and as an output I/V converter for high speed DACs.
CONNECTION DIAGRAM
OFFSET NULL
7
+VS
+IN 3
6
OUTPUT
5
CCOMP
AD829
TOP VIEW
(Not to Scale)
–VS 4
00880-001
8
–IN 2
OFFSET NULL 1
NC
OFFSET
NULL
NC
OFFSET
NULL
NC
Figure 1. 8-Lead PDIP (N), CERDIP (Q), and SOIC (R)
3
2
1
20 19
18 NC
NC 4
–IN 5
+IN 7
17 +V
TOP VIEW
(Not to Scale)
16 NC
15 OUTPUT
14 NC
NC = NO CONNECT
NC
NC
10 11 12 13
CCOMP
9
–V
NC 8
00880-002
NC 6
AD829
NC
High speed
120 MHz bandwidth, gain = −1
230 V/µs slew rate
90 ns settling time to 0.1%
Ideal for video applications
0.02% differential gain
0.04° differential phase
Low noise
1.7 nV/√Hz input voltage noise
1.5 pA/√Hz input current noise
Excellent dc precision
1 mV maximum input offset voltage (over temperature)
0.3 µV/°C input offset drift
Flexible operation
Specified for ±5 V to ±15 V operation
±3 V output swing into a 150 Ω load
External compensation for gains 1 to 20
5 mA supply current
Available in tape and reel in accordance with EIA-481A standard
Figure 2. 20-Terminal LCC
Operating as a traditional voltage feedback amplifier, the AD829
provides many of the advantages that a transimpedance amplifier
offer. A bandwidth >50 MHz can be maintained for a range of
gains through the replacement of the external compensation
capacitor. The AD829 and the transimpedance amplifier are both
unity-gain stable and provide similar voltage noise performance
(1.7 nV/√Hz); however, the current noise of the AD829
(1.5 pA/√Hz) is less than 10% of the noise of transimpedance
amplifiers. The inputs of the AD829 are symmetrical.
PRODUCT HIGHLIGHTS
1.
2.
3.
4.
5.
The input voltage noise of 2 nV/√Hz, current noise of
1.5 pA/√Hz, and 50 MHz bandwidth for gains of 1 to 20
make the AD829 an ideal preamp.
A differential phase error of 0.04 and a 0.02% differential
gain error, at the 3.58 MHz NTSC, 4.43 MHz PAL, and
SECAM color subcarrier frequencies, make the op amp an
outstanding video performer for driving reverse-terminated
50 Ω and 75 Ω cables to ±1 V (at their terminated end).
The AD829 can drive heavy capacitive loads.
Performance is fully specified for operation from ±5 V
to ±15 V supplies.
The AD829 is available in PDIP, CERDIP, and small outline
packages. Chips and MIL-STD-883B parts are also available.
The 8-lead SOIC is available for the extended temperature
range (−40°C to +125°C).
Rev. I
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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