AD8013

REV. A

–12–

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). This circuit takes advantage of the very low

crosstalk between Channels 2 and 3 to achieve the OFF channel

isolation shown in Figure 40. This circuit can achieve

differential gain and phase of 0.03% and 0.07

° respectively.

R1

2k

Ω

R3

10

Ω

R4

10

Ω

R2

2k

Ω

R5

845

Ω

R6

845

Ω

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

100M

–8

–1

–2

–3

–4

–5

–6

–7

–40

–50

–60

–70

–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

The AD8013 can be used to build a circuit for switching between

any two arbitrary gains while maintaining a constant input

impedance. The example of Figure 41 shows a circuit for switching

between a noninverting gain of 1 and an inverting gain of 1. The

total time for channel switching and output voltage settling is

about 80 ns.

6

5

4

1

7

+5V

DIS 1

698

Ω 698Ω

15

Ω

10

9

3

11

8

–5V

DIS 3

845

Ω

1k

845

Ω

1k

2k

13

14

12

50

Ω

100

Ω

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

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

14-Lead Plastic DIP (N-14)

14

17

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)

14

8

7

1

0.3444 (8.75)

0.3367 (8.55)

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)

0.0099 (0.25)

x 45

°