MAX4634ETB(2003) Просмотр технического описания (PDF) - Maxim Integrated

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MAX4634ETB
(Rev.:2003)

Fast, Low-Voltage, 4Ω, 4-Channel CMOS Analog Multiplexer

Maxim Integrated 

Fast, Low-Voltage, 4Ω,

4-Channel CMOS Analog Multiplexer

Pin Description

PIN

µMAX/

THIN QFN

1

2

3

4

5

6

7

8

9

10

NAME

A0

NO1

GND

NO3

EN

V+

NO4

COM

NO2

A1

FUNCTION

Address Input

Normally Open Switch 1

Ground

Normally Open Switch 3

Enable Logic Input

Positive Supply Voltage

Normally Open Switch 4

Analog Switch Common Terminal

Normally Open Switch 2

Address Input

+5V

D1

V+

MAX4634

*

*

COM

NO

*

*

D2

GND

* INTERNAL PROTECTION DIODES

Figure 1. Overvoltage Protection Using External Blocking Diodes

Detailed Description

The MAX4634 is a low-on-resistance, low-voltage ana-

log multiplexer that operates from a +1.8V to +5.5V sin-

gle supply. CMOS switch construction allows pro-

cessing of analog signals that are within the supply volt-

age range (GND to V+).

To disable all switch channels, drive EN low. All four inputs

and COM become high impedance during this state. If the

disable feature is not needed, connect EN to V+.

Applications Information

Power-Supply Sequencing and

Overvoltage Protection

Proper power-supply sequencing is recommended for

all CMOS devices. Always apply V+ before applying

analog signals or logic inputs, especially if the analog or

logic signals are not current limited. If this sequencing is

not possible, and if the analog or logic inputs are not

current limited to < 20mA, add a small-signal diode

(D1) as shown in Figure 1. If the analog signal can dip

below GND, add D2. Adding protection diodes

reduces the analog signal range to a diode drop (about

0.7V) below V+ for D1 or to a diode drop above ground for

D2. The addition of diodes does not affect leakage. On-

resistance increases by a small amount at low supply volt-

ages. Maximum supply voltage (V+) must not exceed 6V.

Protection diodes D1 and D2 also protect against some

overvoltage situations. A fault voltage up to the

absolute maximum rating at an analog signal input

does not damage the device, even if the supply voltage

is below the signal voltage.

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