AD818_15 Datasheet, PDF (13/15 Pages) Analog Devices – Low Cost, Low Power Video Op Amp

DIFFERENTIAL LINE RECEIVER
The differential receiver circuit of Figure 9 is useful for many
applications—from audio to video. It allows extraction of a low
level signal in the presence of common-mode noise, as shown in
Figure 10.
1k⍀
V_B
2pF
1k⍀
+5V
0.01␮F
2.2␮F
DIFFERENTIAL
INPUT
1k⍀
V_A
AD818
V_OUT
0.01␮F
–5V
1k⍀
2pF
2.2␮F
OUTPUT
Figure 9. Differential Line Receiver
100
90 ^1V
V_A
20ns
AD818
A HIGH SPEED, 3-OP AMP IN AMP
The circuit of Figure 11 uses three high speed op amps: two
AD818s and an AD817. This high speed circuit lends itself well
to CCD imaging and other video speed applications. It has the
optional flexibility of both dc and ac trims for common-mode
rejection, plus the ability to adjust for minimum settling time.
+15V
10␮F
COMMON
10␮F
–15V
EACH AMPLIFIER
+V_S
0.1␮F 1␮F
PIN 7
EACH
AMPLIFIER
0.1␮F
0.1␮F ^1␮F
–V_S
0.1␮F
PIN 4
EACH
AMPLIFIER
–V_IN
A1
AD818
1k⍀
5pF
2pF
R_G
5pF
1k⍀
A2
AD818
+V_IN
SETTLING
2pF–8pF
TIME AC
CMR ADJUST
1k⍀
1k⍀
A3
1k⍀
AD818
3pF
970⍀
50⍀
DC CMR
ADJUST
V_OUT
R_L
2k⍀
2V
10
0%
OUTPUT
Figure 10. Performance of Line Receiver, R_L = 150 W,
G = +2
BANDWIDTH, SETTLING TIME, AND TOTAL HARMONIC DISTORTION VS. GAIN
GAIN
3
10
100
SMALL
CADJ SIGNAL
R_G (pF) BANDWIDTH
1k⍀ 2–8
222⍀ 2–8
20⍀ 2–8
14.7MHz
4.5MHz
960kHz
SETTLING
TIME
TO 0.1%
200ns
370ns
2.5␮s
THD + NOISE
BELOW INPUT LEVEL
@ 10kHz
82dB
81dB
71dB
Figure 11. High Speed 3-Op Amp In Amp
REV. D
–13–