TLH6744

February 1995

LM9044 Lambda Sensor Interface Amplifier

General Description

The LM9044 is a precision differential amplifier specifically

designed for operation in the automotive environment Gain

accuracy is guaranteed over the entire automotive tempera-

to package assembly The input circuitry has been specifi-

cally designed to reject common-mode signals as much as

3V below ground on a single positive power supply This

facilitates the use of sensors which are grounded at the

engine block while the LM9044 itself is grounded at chassis

potential An external capacitor sets the maximum operating

frequency of the amplifier thereby filtering high frequency

transients Both inputs are protected against accidental

shorting to the battery and against load dump transients

The input impedance is typically 1 MX

The output op amp is capable of driving capacitive loads

and is fully protected Also internal circuitry has been pro-

vided to detect open circuit conditions on either or both in-

puts and force the output to a ‘‘home’’ position (a ratio of

the external reference voltage)

Features

Y

Normal circuit operation guaranteed with inputs up to

3V below ground on a single supply

Y

Gain factory trimmed and guaranteed over temperature

Y

Low power consumption (typically 1 mA)

Y

Fully protected inputs

Y

Input open circuit detection

Y

Operation guaranteed over the entire automotive tem-

Y

Single supply operation

Schematic and Connection Diagrams

TLH6744 – 1

Plastic Chip Carrier Package

Pins 1 3 4 6 8 9 10 11 13 14 16 18 19 are

trim pins and should be left floating

TLH6744 – 6

Top View

Order Number LM9044V

See NS Package Number V20A

C1995 National Semiconductor Corporation

RRD-B30M115Printed in U S A