LM324: LMV324AIDR and LM324ADR/Query

shivangi tanwar

Prodigy 30 points

Part Number: LM324

Hey,

Please note that we're using LMV324AIDR and LM324ADR ICs in our ATL-140 Design, Please refer to our query-

Please note that we're using the OPAMP IC as Buffer.

1. Please note that Voltage at EXT_ADC1 would be around 5.5V.

2. Please refer to the Connection on OPAMP, please note that VCC is 3.3V.

Can you please help to check with your team, will there be any issue if we use the OP AMP circuit like this?

11 months ago

0 Clemens Ladisch 11 months ago

Guru 280680 points

This voltage is inside the absolute maximum ratings, so the device will not be damaged.

This voltage is outside the valid common-mode voltage range, so the behaviour of the output is not guaranteed. (In practice, it will try to go towards the positive rail; see section 2.2 of the Application Design Guidelines for LM324 and LM358 Devices.)

0 shivangi tanwar 11 months ago in reply to Clemens Ladisch

Prodigy 30 points

Hey Clemens,

Please refer to the queries mentioned below-

1. You're talking about the absolute maximum ratings- 30V, right? IC won't get damaged if input is within this range?

2. It means even if we provide 3.3V power supply at VCC, the output may increase from 3.3V to 5.5V (if we are providing 5.5V at the input of the opamp)??

0 Clemens Ladisch 11 months ago in reply to shivangi tanwar

Guru 280680 points

1. Correct.

2. No, the output will try to go towards 3.3 V, but will not reach it (see the V_OH specification).

0 Ron Michallick 11 months ago

TI__Guru**** 150296 points

Hello Shivangi,

The output range of LM324 is about 0V to 1.8V at 25C and less range at -40C. If sinking much output current then things get worse.

The output range of LM324A is better, 0V to 3.3V

For both, the valid input common mode range doesn't go up to 3.3V

Why was 5.5V chosen for EXT_ADC1?

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LM324: LMV324AIDR and LM324ADR/Query