LM2904B-Q1: behaviour during no power supply

Josef Warta

Part Number: LM2904B-Q1
Other Parts Discussed in Thread: LM2904B

I have a question to the LM2904B operational amplifier, which we have in our motor current ripple module.

The OP will be supplied by charge pump voltage and works fine, if we have it in stable mode.

To reduce the current flow out of the charge pump we want to disable this supply if no motor is active.

Can there be a damage of the LM2904B, if the supply is disabled, but there will be some voltage with maximum Vbat on the input lines?

Many Thanks

Josef

9 months ago

0 Clemens Ladisch 9 months ago

Guru 264040 points

No; the absolute maximum ratings allow voltages higher than V_CCx.

0 Martin Blinzler 9 months ago in reply to Clemens Ladisch

Prodigy 130 points

Hi, so you are referring to the 7.1 Absolute Maximum Raings in which it is mentioned a MAX input voltage up to 40V. For me it was just unclear, if this is also ok, when the device is not supplied. Thank you

0 Jerry Madalvanos 9 months ago in reply to Martin Blinzler

TI__Mastermind 25951 points

Hey Martin and Josef,

The absolute maximum rating is not given relative to V+, or with a specified V+ value. Another example of this is the OPAx310.

Here we have made it more clear that there is no input diode to V+ in the footnotes of the abs max table.

Best,
Jerry

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LM2904B-Q1: behaviour during no power supply