TLH7758

December 1994

LM108LM208LM308 Operational Amplifiers

General Description

The LM108 series are precision operational amplifiers hav-

ing specifications a factor of ten better than FET amplifiers

g

20V and have sufficient supply rejection to use unregulat-

ed supplies Although the circuit is interchangeable with and

uses the same compensation as the LM101A an alternate

compensation scheme can be used to make it particularly

insensitive to power supply noise and to make supply by-

pass capacitors unnecessary

The low current error of the LM108 series makes possible

many designs that are not practical with conventional ampli-

fiers In fact it operates from 10 MX source resistances

introducing less error than devices like the 709 with 10 kX

sources Integrators with drifts less than 500 mVsec and

analog time delays in excess of one hour can be made us-

ing capacitors no larger than 1 mF

a

70 C

Features

Y

Maximum input bias current of 30 nA over temperature

Y

Offset current less than 400 pA over temperature

Y

Supply current of only 300 mA even in saturation

Y

Guaranteed drift characteristics

Compensation Circuits

Standard Compensation Circuit

TLH7758 – 1

Alternate Frequency Compensation

TLH7758 – 2

Improves rejection of power supply noise by a factor of ten

Feedforward Compensation

TLH7758 – 3

C1995 National Semiconductor Corporation

RRD-B30M115Printed in U S A