LM2903-Q1: Question if this device operates like normally when VCC=0V

RYO

Intellectual 2000 points

Part Number: LM2903-Q1
Other Parts Discussed in Thread: TINA-TI,

Hello all,

Is it possible for LM2903-Q1 to operate when VCC=GND=0V and input differential voltage at IN+ or IN-? In the TINA-TI, it seems to output as normal operation when VCC=GND. Does this device possibly work by leakage when output impedance is very high?

Thanks,
RYO

over 6 years ago

0 Paul Grohe over 6 years ago

TI__Guru 68316 points

Hello Ryo,

No. The output will be high impedance when VCC=GND=0V. The output is a bipolar NPN so there needs to be at least 1V on the supply to even begin to turn on the output transistor.

Also note that you have the supply pins backwards (V+ is connected to GND). The symbols are "upside down". The model is being used incorrectly...

When the inputs are taken above V+, the input devices reverse bias and turn off.

For more info, please see the following application note:

Application Design Guidelines for LM339/LM393/TL331 Family Comparators

0 RYO over 6 years ago in reply to Paul Grohe

TI__Intellectual 2000 points

Thank you, Paul.

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LM2903-Q1: Question if this device operates like normally when VCC=0V