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a

ADG466/ADG467

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© Analog Devices, Inc., 1998

Triple and Octal

Channel Protectors

FUNCTIONAL BLOCK DIAGRAMS

ADG466

ADG467

OUTPUT CLAMPED

GENERAL DESCRIPTION

The ADG466 and ADG467 are triple and octal channel pro-

tectors, respectively. The channel protector is placed in series

with the signal path. The channel protector will protect sensitive

components from voltage transience in the signal path whether

the power supplies are present or not. Because the channel

protection works whether the supplies are present or not, the

channel protectors are ideal for use in applications where

correct power sequencing can’t always be guaranteed (e.g., hot-

insertion rack systems) to protect analog inputs. This is dis-

cussed further, and some example circuits are given in the

Applications section of this data sheet.

Each channel protector has an independent operation and con-

sists of an n-channel MOSFET, a p-channel MOSFET and an

n-channel MOSFET, connected in series. The channel protec-

tor behaves just like a series resistor during normal operation,

0 V), one of the MOSFETs will switch off, clamping the output

protection is provided in the event of an overvoltage or power

loss. The channel protectors can withstand overvoltage inputs

from –40 V to +40 V. See the Circuit Information section of

this data sheet.

The ADG466 and ADG467 can operate off both bipolar and

unipolar supplies. The channels are normally on when power is

connected and open circuit when power is disconnected. With

power supplies of

±15 V, the on-resistance of the ADG466 and

FEATURES

Fault and Overvoltage Protection up to

40 V

Signal Paths Open Circuit with Power Off

44 V Supply Maximum Ratings

Low On Resistance

ADG466/ADG467 60

typ

1 nA Max Path Current Leakage @ +25 C

max)

Low Power Dissipation 0.8

W typ

Latch-Up Proof Construction

APPLICATIONS

ATE Equipment

Sensitive Measurement Equipment

Hot-Insertion Rack Systems

ADG467 is 60

Ω typ with a leakage current of ±1 nA max.

When power is disconnected, the input leakage current is ap-

proximately

±5 nA typ.

The ADG466 is available in 8-lead DIP, SOIC and

µSOIC

packages. The ADG467 is available in an 18-lead SOIC package

and a 20-lead SSOP package.

PRODUCT HIGHLIGHTS

1. Fault Protection.

The ADG466 and ADG467 can withstand continuous volt-

age inputs from –40 V to +40 V. When a fault occurs due to

the power supplies being turned off or due to an overvoltage

being applied to the ADG466 and ADG467, the output is

clamped. When power is turned off, current is limited to the

microampere level.

2. Low Power Dissipation.

ADG466/ADG467 60

Ω typ.

4. Trench Isolation Latch-Up Proof Construction.

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

thereby preventing latch-up.