LM324B: Input voltage with no power supply

aurelienr

Intellectual 360 points

Part Number: LM324B
Other Parts Discussed in Thread: LM324,

Hello,

The datasheet indicates that input voltage can be within -0.3V to +40V, without relation to VCC power supply.

Can you please confirm that :

- the device will not damaged by an input voltage on the IN+/- inputs when it is not powered (VCC=0V) ?

- if a voltage is present on the input before a voltage is applied on power supply, the part will start and run without problem

Thank you

Aurelien

10 months ago

+1 Clemens Ladisch 10 months ago

Guru 265250 points

Correct. Section 2.2 of the Application Design Guidelines for LM324 and LM358 Devices says:

Because the inputs have no internal diodes to V_CC, the input voltage can exceed the V_CC voltage. If this occurs, the input will block current flow due to a reverse biased diode forming in the input PNP transistor. Current flow is blocked even if V_CC equals 0 V.

0 aurelienr 10 months ago in reply to Clemens Ladisch

Intellectual 360 points

Thank you I missed this document :)

0 Clemens Ladisch 10 months ago in reply to aurelienr

Guru 265250 points

… because it's linked to from the LM324 page, but not from the LM324B page.

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LM324B: Input voltage with no power supply