AD812
Operation Using a Single Supply
90
PHASE
GAIN
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.
0
V
= 5V
S
0.5
0
–90
–180
–270
–0.5
–1.0
–1.5
–2.0
–2.5
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.
–3.0
–3.5
1
10
100
1000
FREQUENCY – MHz
Figure 54. Closed-Loop Gain and Phase vs. Frequency,
Circuit of Figure 53
649⍀
649⍀
C3
30F
R3
1k⍀
+V
S
C2
1V
50ns
1F
R1
9k⍀
C
OUT
75⍀
CABLE
100
90
8
47F
75⍀
V
IN
C1
2F
V
OUT
AD812
V
IN
75⍀
4
R2
11.8k⍀
V
OUT
Figure 53. Biasing for Single Supply Operation
10
0%
500mV
Figure 55. Pulse Response of the Circuit of Figure 53 with
VS = 5 V
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
8-Lead Plastic DIP
(N-8)
8-Lead Plastic SOIC
(SO-8)
0.39 (9.91)
0.1968 (5.00)
0.1890 (4.80)
8
5
4
0.25
(6.35)
8
1
5
4
0.1574 (4.00)
0.1497 (3.80)
0.2440 (6.20)
0.2284 (5.80)
1
0.325 (8.25)
0.300 (7.62)
0.060 (1.52)
0.015 (0.38)
PIN 1
0.10
0.195 (4.95)
0.115 (2.93)
0.165 ؎0.01
(4.19 ؎0.25)
PIN 1
0.0688 (1.75)
0.0532 (1.35)
0.0196 (0.50)
0.0099 (0.25)
0.0098 (0.25)
0.0040 (0.10)
0.125 (3.18)
MIN
0.015 (0.381)
0.008 (0.204)
SEATING
PLANE
0.018 ؎0.003
0.033 (0.84)
NOM
8؇
0؇
0.0500
(1.27)
BSC
0.0192 (0.49)
0.0138 (0.35)
(0.46 +0.08) (2.54)
BSC
SEATING
PLANE
0.0098 (0.25)
0.0075 (0.19)
0.0500 (1.27)
0.0160 (0.41)
REV. B
–16–
ADI [ ADI ]
