Low-Voltage, CMOS Analog

Multiplexers/Switches

8

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__________Applications Information

Power-Supply Considerations

Overview

The MAX4581/MAX4582/MAX4583 construction is typi-

cal of most CMOS analog switches. They have three

to drive the internal CMOS switches and set the limits of

the analog voltage on any switch. Reverse ESD-

protection diodes are internally connected between

will conduct. During normal operation, these and other

reverse-biased ESD diodes leak, forming the only cur-

Virtually all the analog leakage current comes from the

ESD diodes. Although the ESD diodes on a given signal

pin are identical and therefore fairly well balanced, they

are reverse biased differently. Each is biased by either

leakages will vary as the signal varies. The

difference in

tutes the analog-signal-path leakage current. All analog

leakage current flows between each pin and one of the

supply terminals, not to the other switch terminal. This is

why both sides of a given switch can show leakage cur-

rents of either the same or opposite polarity.

There is no connection between the analog-signal

paths and GND.

Pin Description

Note: Input and output pins are identical and interchangeable. Any may be considered an input or output; signals pass equally well

in both directions.

PIN

16

16

16

Positive Analog and Digital Supply Voltage Input

MAX4583

MAX4582

MAX4581

15

Y

—

Y0, Y1, Y2, Y3

9

C

4

Z

3

Z1

5

Z0

NAME

—

X0–X7

—

X

—

X0, X1, X2, X3

14

X

2

Y0

1

Y1

12

X0

13

X1

10

B

11

A

8

GND

7

6

Enable

—

3

Analog Switch “Y” Output

—

1, 5, 2, 4

Analog Switch “Y” Inputs 0–3

9

—

Digital Address “C” Input

—

—

Analog Switch “Z” Output

—

—

Analog Switch “Z” Normally Open Input

—

—

Analog Switch “Z” Normally Closed Input

FUNCTION

13, 14, 15,

12, 1, 5, 2, 4

—

Analog Switch Inputs 0–7

3

—

Analog Switch Output

—

12, 14, 15, 11

Analog Switch “X” Inputs 0–3

—

13

Analog Switch “X” Output

—

—

Analog Switch “Y” Normally Closed Input

—

—

Analog Switch “Y” Normally Open Input

—

—

Analog Switch “X” Normally Closed Input

—

—

Analog Switch “X” Normally Open Input

10

9

Digital Address “B” Input

11

10

Digital Address “A” Input

8

8

Ground. Connect to digital ground. (Analog signals have no

7

7

Negative Analog Supply-Voltage Input. Connect to GND for

single-supply operation.

6

6

Digital Enable Input. Normally connect to GND. Can be driven

to logic high to set all switches off.