8-Channel Fault-Protected

Analog Multiplexer

ADG528F

Rev. F

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FEATURES

Low on resistance (300 Ω typical)

Fast switching times

Low power dissipation (3.3 mW maximum)

Fault and overvoltage protection (−40 V to +55 V)

All switches off with power supply off

Analog output of on channel clamped within power

supplies if an overvoltage occurs

Latch-up proof construction

Break-before-make construction

TTL and CMOS compatible inputs

APPLICATIONS

Existing multiplexer applications (both fault-protected and

nonfault-protected)

New designs requiring multiplexer functions

FUNCTIONAL BLOCK DIAGRAM

S1

S8

A0

D

ADG528F

A1 A2 EN

1 OF 8

DECODER

WR

RS

Figure 1.

GENERAL DESCRIPTION

comprising eight single channels. This multiplexer provides

fault protection. Using a series n-channel, p-channel, n-channel

MOSFET structure, both device and signal source protection is

provided in the event of an overvoltage or power loss. The

multiplexer can withstand continuous overvoltage inputs

from −40 V to +55 V. During fault conditions, the multiplexer

input (or output) appears as an open circuit and only a few

nanoamperes of leakage current will flow. This protects not

only the multiplexer and the circuitry driven by the multiplexer,

but also protects the sensors or signal sources that drive the

multiplexer.

The ADG528F switches one of eight inputs to a common output

as determined by the 3-bit binary address lines A0, A1, and A2.

The ADG528F has on-chip address and control latches that

facilitate microprocessor interfacing. An EN input on the device

is used to enable or disable the device. When disabled, all channels

are switched off.

PRODUCT HIGHLIGHTS

1.

Fault protection.

The ADG528F can withstand continuous voltage inputs

from −40 V to +55 V. When a fault occurs due to the

power supplies being turned off, all the channels are turned

off and only a leakage current of a few nanoamperes flows.

2.

On channel turns off while fault exists.

3.

4.

Fast switching times.

5.

Break-before-make switching.

Switches are guaranteed break-before-make so that input

signals are protected against momentary shorting.

6.

Trench isolation eliminates latch-up.

A dielectric trench separates the p-channel and n-channel

MOSFETs thereby preventing latch-up.