AD812
REV. B
–16–
Operation Using a Single Supply
The AD812 will operate with total supply voltages from 36 V
down to 2.4 V. With proper biasing (see Figure 53), it can be an
outstanding single supply video amplifier. Since the input and
output voltage ranges extend to within 1 volt of the supply rails,
it will handle a 1.3 V p-p signal on a single 3.3 V supply, or a
3 V p-p signal on a single 5 V supply. The small signal, 0.1 dB
bandwidths will exceed 10 MHz in either case, and the large
signal bandwidths will exceed 6 MHz.
The capacitively coupled cable driver in Figure 53 will achieve
outstanding differential gain and phase errors of 0.07% and 0.06
degrees respectively on a single 5 V supply. Resistor R2, in this
circuit, is selected to optimize the differential gain and phase by
operating the amplifier in its most linear region. To optimize the
circuit for a 3 V supply, a value of 8 kΩ is recommended for R2.
AD812
8
4
V
IN
R2
11.8kV
V
OUT
75V
75V
+V
S
R3
1kV
75V
CABLE
R1
9kV
C1
2mF
C3
30mF
649V
649V
C
OUT
47mF
C2
1mF
Figure 53. Biasing for Single Supply Operation
8-Lead Plastic DIP
(N-8)
8
14
5
PIN 1
SEATING
PLANE
0.060 (1.52)
0.015 (0.38)
0.165 60.01
(4.19 60.25)
0.10
(2.54)
BSC
0.325 (8.25)
0.300 (7.62)
0.015 (0.381)
0.008 (0.204)
0.195 (4.95)
0.115 (2.93)
0.39 (9.91)
0.25
(6.35)
0.125 (3.18)
MIN
0.018 60.003
(0.46 +0.08)
0.033 (0.84)
NOM
8-Lead Plastic SOIC
(SO-8)
0.1968 (5.00)
0.1890 (4.80)
85
41
0.2440 (6.20)
0.2284 (5.80)
PIN 1
0.1574 (4.00)
0.1497 (3.80)
0.0688 (1.75)
0.0532 (1.35)
SEATING
PLANE
0.0098 (0.25)
0.0040 (0.10)
0.0192 (0.49)
0.0138 (0.35)
0.0500
(1.27)
BSC
0.0098 (0.25)
0.0075 (0.19)
0.0500 (1.27)
0.0160 (0.41)
88
08
0.0196 (0.50)
0.0099 (0.25)
3 458
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
PRINTED IN U.S.A.
C1859b–0–9/98
–0.5
–3.0
1 10 1000100
–1.0
–1.5
–2.0
–2.5
0
0.5
–270
–180
–90
0
FREQUENCY – MHz
CLOSED-LOOP GAIN – dB
PHASE SHIFT – Degrees
–3.5
V
S
= 5V
90
GAIN
PHASE
Figure 54. Closed-Loop Gain and Phase vs. Frequency,
Circuit of Figure 53
10
90
100
0%
500mV
1V
50ns
V
IN
V
OUT
Figure 55. Pulse Response of the Circuit of Figure 53 with
V
S
= 5 V
