High Voltage OpAmp PR2201 / PR2202

Application Notes

FREQUENCY DEPENDENCE

At very high slew rates, especially at the supply

voltage, but also at all other pins, integrated

circuits can latch, leading to a high current flow

and usually fast destruction of the IC and its

environment.

Although during IC design precautions were

taken to suppress latch-up, this can become

critical for high-voltage ICs, especially at

voltages above 60 V. The slew rate of the

supply voltage should limited e.g. by means of

an RC-combination.

All other signals should be blocked by

capacitors to avoid sharp transients.

Safety note: Latching circuits can draw very

high currents. To avoid consequential damage

of the power supply and the danger of fire in

case of a failure, it is necessary to limit the

current by resistors, active current limiting

circuits, or fuses.

Differential voltages in excess to the specified

value can damage the input stage.

Note that in a feedback circuit, if at input signals

with high slew rates the output cannot follow

the input, transients with high differential

voltages may occur. This can happen e.g. if the

input signal is connected over a bouncing

mechanical contact.

If such situations cannot be avoided, the input

differential voltage must be limited by an

external protection circuit, e.g. fast Zener

diodes.

OFFSET COMPENSATION (PR2201)

Pins Comp1 and Comp2 allow to compensate

the input offset of the amplifier by means of an

external potentiometer or two trimmable

resistors.

OVERTEMPERATURE PROTECTION

To avoid overheating of the operational

amplifiers, there is a built-in overtemperature

protection. If this is activated, the output will go

to a high-resistance state.

The design of your circuit must consider this

situation. E.g. a feedback loop would be opened

if the opamp shuts down, which in certain

situations may lead to an excess differential

input voltage.

The opamp switches on again when the

temperature has dropped. This usually leads to

intermittent

operation

until

the

overload

condition is resolved.

Generally,

the

overtemperature

shutdown

should be avoided by means of proper thermal

design and avoiding overload situations.

© PREMA Semiconductor GmbH 2006-2014 I rev. 1014

Page 4/8