High-Speed, Low-Power, Single-Supply,

Multichannel, Video Multiplexer-Amplifiers

14

______________________________________________________________________________________

The bypass capacitors should include a 100nF, ceram-

ic surface-mount capacitor between each supply pin

and the ground plane, located as close to the package

as possible. Optionally, place a 10µF tantalum capaci-

tor at the power-supply pins’ point of entry to the PC

board to ensure the integrity of incoming supplies. The

power-supply trace should lead directly from the tanta-

parasitic inductance, keep PC traces short and use sur-

face-mount components.

If input termination resistors and output back-termination

resistors are used, they should be surface-mount types,

and should be placed as close to the IC pins as possible.

Video Line Driver

The MAX4310–MAX4315 are well-suited to drive coaxial

transmission lines when the cable is terminated at both

ends, as shown in Figure 5. Cable frequency response

can cause variations in the signal’s flatness.

MAX4313

75

Ω

8

OUT

IN0

IN1

4

5

17

GND

A0

75

Ω

500

Ω

500

Ω

75

Ω CABLE

OUT

75

Ω

75

Ω

75

Ω CABLE

75

Ω CABLE

Figure 5. Video Line Driver

100M

1G

-6

4

3

2

0

-1

-2

-3

-4

-5

1

100k

1M

10M

FREQUENCY (Hz)

10pF LOAD

5pF LOAD

15pF LOAD

Figure 6. Small-Signal Gain vs. Frequency with Capacitive

Load and No Isolation Resistor

MAX4313

8

OUT

IN0

IN1

4

5

17

GND

A0

500

Ω

500

Ω

75

Ω

75

Ω

75

Ω CABLE

75

Ω CABLE

Capacitive Loads

10

15

20

25

30

0

50

100

150

200

250

CAPACITIVE LOAD (pF)

Figure 8. Optimal Isolation Resistance vs. Capacitive Load

100M

1G

-6

4

3

2

0

-1

-2

-3

-4

-5

1

100k

1M

10M

FREQUENCY (Hz)

47pF LOAD

90pF LOAD

120pF LOAD

Figure 9. Small-Signal Gain vs. Frequency with Load

Capacitance and 27

Ω Isolation Resistor