Datasheet

AD847
REV. F
–11–
A High Speed, Three Op-Amp In-Amp
The circuit of Figure 26 lends itself well to CCD imaging and
other video speed applications. It uses two high speed CB pro-
cess op-amps: Amplifier A3, the output amplifier, is an AD847.
The input amplifier (A1 and A2) is an AD827, which is a dual
version of the AD847. This circuit has the optional flexibility of
both dc and ac trims for common-mode rejection, plus the abil-
ity to adjust for minimum settling time.
PIN 7 AD847,
PIN 8 AD827
1µF
1µF
0.1µF
0.1µF
0.1µF
0.1µF
EACH
AMPLIFIER
+15V
–15V
COMM
+V
S
–V
S
10µF
10µF
PIN 4
AD847 & AD827
AD847
2–8pF
SETTLING TIME
AC CMR ADJUST
2kΩ
1.87kΩ
2kΩ
2kΩ
5pF
R
G
V
OUT
200Ω
DC CMR
ADJUST
2kΩ
R
L
CIRCUIT GAIN = + 1
2000Ω
G
R
IN
+V
2
3
1
A1
1/2
AD827
1kΩ
–V
IN
6
5
7
A2
1/2
AD827
1kΩ
2
3
6
A3
100Hz
1kHz
10kHz
100kHz
1MHz
88.3dB
87.4dB
86.2dB
67.4dB
47.1dB
INPUT
FREQUENCY
CMRR
THD + NOISE
BELOW INPUT
LEVEL
@ 10kHz
1
2
10
100
OPEN
2kΩ
226Ω
20Ω
2–8
2–8
2–8
2–8
16.1MHz
14.7MHz
4.5MHz
660kHz
200ns
200ns
370ns
2.5µs
82dB
82dB
81dB
71dB
GAIN R
G
SMALL
SIGNAL
BANDWIDTH
SETTLING
TIME
TO 0.1%
C
(pF)
ADJ
BANDWIDTH, SETTLING TIME AND TOTAL HARMONIC DISTORTION VS. GAIN
Figure 26. A High Speed In-Amp Circuit for Data Acquisition