AD829JNZ Datasheet, PDF (16/20 Pages) Analog Devices – High Speed, Low Noise Video Op Amp

AD829
HIGH GAIN VIDEO BANDWIDTH, 3-OP-AMP
INSTRUMENTATION AMPLIFIER
Figure 48 shows a 3-op-amp instrumentation amplifier circuit
that provides a gain of 100 at video bandwidths. At a circuit gain of
100, the small signal bandwidth equals 18 MHz into a FET probe.
Small signal bandwidth equals 6.6 MHz with a 50 Ω load. The
0.1% settling time is 300 ns.
Data Sheet
The input amplifiers operate at a gain of 20, while the output
op amp runs at a gain of 5. In this circuit, the main bandwidth
limitation is the gain/bandwidth product of the output amplifier.
Extra care should be taken while breadboarding this circuit
because even a couple of extra picofarads of stray capacitance at the
compensation pins of A1 and A2 will degrade circuit bandwidth.
+V_IN
R_G
210Ω
+V_IN
3pF
5 (G = 20)
3
A1
AD829 ⁶
2
2pF TO 8pF
SETTLING TIME
AC CMR ADJUST
1kΩ
2kΩ
1pF
200Ω
2
A3
1pF
200Ω
AD848
6
3
2kΩ
5 ^{(G = 5)}
3pF
970Ω
2
A2
AD829 ⁶
3
5 (G = 20)
DC CMR
ADJUST
50Ω
3pF
4000Ω
CIRCUIT GAIN = _RG + 1 5
+15V
COMM
–15V
2kΩ
INPUT
FREQUENCY CMRR
100Hz
1MHz
10MHz
64.6dB
44.7dB
23.9dB
+V_S
10µF
0.1µF
1µF
10µF
0.1µF
1µF
–V_S
Figure 48. High Gain Video Bandwidth, 3-Op-Amp In-Amp Circuit
PIN 7
0.1µF
EACH
AMPLIFIER
0.1µF
PIN 4
Rev. I | Page 16 of 20