_______________Detailed Description

The MAX4137/MAX4138 are 1-input/4-output video dis-

tribution amplifiers. The MAX4137 is configured for a

fixed gain of +2, while the MAX4138 features external

gain control (feedback) for closed-loop gains of 2V/V or

greater.

Each output provides sufficient current to drive five

150

Ω loads. However, distortion will increase when driving

multiple loads. The TTL/CMOS-compatible digital control

(

SEL_) enables or disables each output amplifier. When

the

SEL_ control input is low, the amplifier is enabled;

when it is high, the amplifier is disabled and presents a

high-impedance output. The enable/disable or

disable/enable time is under 25ns, which is useful

in multiplexing, pixel switching, or picture-in-picture

applications.

Each device has an input amplifier, which buffers the

input from any switching glitches that may be taking

place at the output stage, and provides a high-

impedance, low-capacitance input. The separate input

buffer allows a true high output impedance when an

amplifier is disabled.

The outputs are protected against short circuits to

ground. However, power-dissipation limits preclude

shorting all output channels to ground. See the

Power-

Dissipation Considerations section for details.

1-Input/4-Output

Video Distribution Amplifiers

_______________________________________________________________________________________

7

______________________________________________________________Pin Description

Output 4

10

10

14

14

When low, enables output channel OUT3. When high, disables output channel OUT3.

15

15

Analog Ground

4, 9, 21

4, 9, 18, 21

Output 2

5

5

Negative Supply for Output Amplifiers. Connect to -5V.

6, 7

6, 7

Output 3

8

8

Output 1

3

3

Positive Supply for Output Amplifiers. Connect to +5V.

2, 11

2, 11

FUNCTION

PIN

OUT4

SEL4

SEL3

AGND

OUT2

VEEO

OUT3

OUT1

VCCO

NAME

16

16

VCCI

Positive Supply for Input Amplifier. Connect to +5V.

—

17

RF

Output of Input Amplifier

—

18

RG

Inverting Input

19

19

VEEI

Negative Supply for Input Amplifier. Connect to -5V.

20

20

IN+

Noninverting Input

22

22

SEL2

When low, enables output channel OUT2. When high, disables output channel OUT2.

23

23

SEL1

When low, enables output channel OUT1. When high, disables output channel OUT1.

MAX4137

MAX4138

When low, enables output channel OUT4. When high, disables output channel OUT4.

No Connect. Not internally connected.

1, 12, 13,

24

1, 12, 13,

17, 24

N.C.