LM321MF

APPLICATION SUMMARY

The

LM321MF op amp can operate with a single or dual power supply voltage, has

true-differential inputs, and remain in the linear mode with an input common-mode voltage

change in performance characteristics. At 25°C amplifier operation is possible down to a

minimum supply voltage of 3V.

Large differential input voltages can be easily accommodated and, as input differential

voltage protection diodes are not needed, no large input currents result from large

damaging the device. Protection should be provided to prevent the input voltages from

IC input terminal can be used.

To reduce the power supply drain, the amplifier has a class A output stage for small signal

levels which converts to class B in a large signal mode. This allows the amplifiers to both

source and sink large output currents. Therefore both NPN and PNP external current boost

transistors can be used to extend the power capability of the basic amplifiers. The output

voltage needs to raise approximately 1 diode drop above ground to bias the on-chip vertical

PNP transistor for output current sinking applications.

For AC applications, where the load is capacitively coupled to the output of the amplifier, a

resistor should be used, from the output of the amplifier to ground to increase the class A

bias current and to reduce distortion.

Capacitive loads which are applied directly to the output of the amplifier reduce the loop

stability margin. Values of 50pF can be accommodated using the worst-case non-inverting

unity gain connection. Large closed loop gains or resistive isolation should be used if large

load capacitance must be driven by the amplifier.

The bias network of the

LM321MF establishes a supply current which is independent of the

Output short circuits either to ground or to the positive power supply should be of short

time duration. Units can be destroyed, not as a result of the short circuit current causing

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