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LM2903: Electrical Characteristics Test Circuits

Part Number: LM2903
Other Parts Discussed in Thread: TLC393

I'm trying to test the Electrical Characteristics of the LM2903 on page 10 of the product's datasheet. Some of the parameters I am trying to test (Input Offset Voltage, Large-Signal Differential Voltage Amplification, etc.) are giving me trouble. I would like to know how to correctly test these characteristics or if there are any test circuits for this part that were specifically used to get these parameters. 

  • Hello John,

    The actual test systems we use to measure these are considered intellectual property...so we cannot give you exact circuits. Measuring comparators is more challenging than op-amps as the output is not linear and needs to be converted from the digital to analog domain when testing in the "op amp loop" - and adds some error.

    But some of the old datasheets, such as the TLC393 (p 7-9), give examples of how the measurements are done. The most basic is to apply an accurate triangle wave to the input and find where the trip points are on both the rising and falling ramps.

    The average of the two trip points from zero is the offset. The difference between the two trip points is the hysteresis.

    This TI Labs presentation may help you interpret the specifiations

     TI Precision Labs - Comparators

    Measuring "Large Signal Differential Voltage" is the most difficult of all as it requires accurate (repeatable) measurement of offset voltage, as you are looking for a small percentage shift of the offset voltage.