Application Hints

This device is a quad low power op amp with JFET input de-

down voltages from gate to source and drain eliminating the

need for clamps across the inputs. Therefore, large differen-

tial input voltages can easily be accommodated without a

large increase in input current. The maximum differential in-

put voltage is independent of the supply voltages. However,

neither of the input voltages should be allowed to exceed the

negative supply as this will cause large currents to flow

which can result in a destroyed unit.

Exceeding the negative common-mode limit on either input

will force the output to a high state, potentially causing a re-

versal of phase to the output. Exceeding the negative

common-mode limit on both inputs will force the amplifier

output to a high state. In neither case does a latch occur

since raising the input back within the common-mode range

again puts the input stage and thus the amplifier in a normal

operating mode.

Exceeding the positive common-mode limit on a single input

will not change the phase of the output; however, if both in-

puts exceed the limit, the output of the amplifier will be forced

to a high state.

The amplifiers will operate with a common-mode input volt-

age equal to the positive supply; however, the gain band-

width and slew rate may be decreased in this condition.

When the negative common-mode voltage swings to within

3V of the negative supply, an increase in input offset voltage

may occur.

Each amplifier is individually biased to allow normal circuit

than these may degrade the common-mode rejection and re-

strict the output voltage swing.

The amplifiers will drive a 10 k

over the full temperature range. If the amplifier is forced to

drive heavier load currents, however, an increase in input

offset voltage may occur on the negative voltage swing and

finally reach an active current limit on both positive and

negative swings.

Small Signal Inverting

DS009156-6

Small Signal Non-Inverting

DS009156-7

Large Signal Inverting

DS009156-8

Large Signal Non-Inverting

DS009156-9

www.national.com

6