
AD8013
REV. A
–12–
C
P
2:1 Video Multiplexer
Configuring two amplifiers as unity gain followers and using the
third to set the gain results in a high performance 2:1 mux
(Figures 39 and 40). T his circuit takes advantage of the very low
crosstalk between Channels 2 and 3 to achieve the OFF channel
isolation shown in Figure 40. T his circuit can achieve
differential gain and phase of 0.03% and 0.07
°
respectively.
V
OUT
V
IN
A
R1
2k
V
IN
B
R3
10
R4
10
R2
2k
R5
845
R6
7
6
5
1
14
13
12
2
8
9
10
3
2
3
DISABLE
DISABLE
Figure 39. 2:1 Mux with High Isolation and Low
Differential Gain and Phase Errors
FREQUENCY – Hz
1G
1M
C
100M
–8
–1
–2
–3
–4
–5
–6
–7
–40
–50
–60
–70
F
–80
0
1
2
–30
10M
GAIN
FEEDTHROUGH
Figure 40. 2:1 Mux ON Channel Gain and Mux OFF Channel
Feedthrough vs. Frequency
Gain Switching
T he AD8013 can be used to build a circuit for switching between
any two arbitrary gains while maintaining a constant input
impedance. T he example of Figure 41 shows a circuit for switching
between a noninverting gain of 1 and an inverting gain of 1. T he
total time for channel switching and output voltage settling is
about 80 ns.
6
5
4
17
+5V
DIS 1
698
698
15
V
OUT
10
9
3
118
–5V
DIS 3
845
1k
845
1k
2k
13
14
12
50
100
V
IN
Figure 41. Circuit to Switch Between Gains of –1 and +1
10
0%
100
90
200ns
500mV
5V
500mV
Figure 42. Switching Characteristic for Circuit of Figure 41
OUT LINE DIME NSIONS
Dimensions shown in inches and (mm).
14-Lead Plastic DIP (N-14)
14
1
7
8
0.795 (20.19)
0.725 (18.42)
0.280 (7.11)
0.240 (6.10)
PIN 1
SEATING
PLANE
0.022 (0.558)
0.014 (0.356)
0.060 (1.52)
0.015 (0.38)
0.210 (5.33)
MAX
0.130
(3.30)
MIN
0.070 (1.77)
0.045 (1.15)
0.100
(2.54)
BSC
0.160 (4.06)
0.115 (2.93)
0.325 (8.25)
0.300 (7.62)
0.015 (0.381)
0.008 (0.204)
0.195 (4.95)
0.115 (2.93)
14-Lead SOIC (R-14)
0.3444 (8.75)
0.3367 (8.55)
14
8
7
1
0.2440 (6.20)
0.2284 (5.80)
0.1574 (4.00)
0.1497 (3.80)
PIN 1
SEATING
PLANE
0.0098 (0.25)
0.0040 (0.10)
0.0192 (0.49)
0.0138 (0.35)
0.0688 (1.75)
0.0532 (1.35)
0.0500
(1.27)
BSC
0.0098 (0.25)
0.0075 (0.19)
0.0500 (1.27)
0.0160 (0.41)
8
°
0
°
0.0196 (0.50)
°