What is the difference between LM231 LM331 and LM331A?

Hello Alvin,

National used the LM1xx, LM2xx and LM3xx to differentiate the markets:

LM1xx = Military (-55 to +125°C)

LM2xx = Industrial (various temp ranges, usually -40 to 85°C)

LM3xx = Consumer (0 to 70°C).

The "A" denotes it is tested to a tighter specification.

They are all the same die, but tested to different limits in production, as denoted in the "Parameter" column. They are interchangeable, but will have different performance, particulalrly over temperature.

In short, the different grades have different specification limits for Gain, Temperature Stability, Offset Voltage, Bias Current, reference voltages and Supply Current.

Regards,