ISL28325, ISL28345

6

September 27, 2011

FN7854.0

Applications Information

Functional Description

The ISL28325 and ISL28345 are dual and quad general purpose

amplifiers featuring low noise vs power consumption. They are

offered in industry standard pinouts in 8 Ld SOIC, 8 Ld MSOP and

14 Ld SOIC packages. Applications for this amplifier include

active filters, medical and analytical instrumentation, power

supply controls, and industrial controls..

Operating Voltage Range

The devices are designed to operate over the 4.5V (±2.25V) to

40V (±20V) range over the -40°C to +125°C temperature range.

For best amplifier performance, decouple the power supply with

a 0.01µF or larger capacitors by placing them close to the supply

pins of the amplifier.

Input ESD Diode Protection

The input terminals (IN+ and IN-) have internal ESD protection

diodes to the positive and negative supply rails, series connected

500

Ω current limiting resistors and an anti-parallel diode pair

across the inputs.

The series resistors limit the high feed-through currents that can

occur in pulse applications when the input dV/dT exceeds the

0.4V/µs slew rate of the amplifier. Without the series resistors, the

input can forward-bias the anti-parallel diodes causing current to

flow to the output resulting in severe distortion and possible diode

failure.

In applications where one or both amplifier input terminals are at

risk of exposure to high voltages beyond the power supply rails,

current limiting resistors may be needed at the input terminal to

limit the current through the power supply ESD diodes to 20mA

max.