LMP8645: Voltage at input terminals

Jay Sashidharan

Part Number: LMP8645

Hi,

After I'm connecting LMP8645 with 3.3v at the V+ and 0v at V-. I can measure 1.5v at +in and -in terminals. According to my understanding I should see a small floating voltage on those terminals but not something as high as 1.5 v this is causing issues on my board. Can you please explain why I'm measuring 1.5v at those terminals, Thanks.

over 5 years ago

0 Guang Zhou over 5 years ago

TI__Mastermind 32340 points

Hi Jay,

The input pins are connected to V+ and V- through some circuitry, in the absence of external driving source, the internal circuitry takes over. The 1.5V observed is most likely due to this effect. However since the pins are high impedance, even though you can measure it, it can be easily overridden.

Can you elaborate why this poses a problem?

Regards, Guang

0 Jay Sashidharan over 5 years ago in reply to Guang Zhou

Prodigy 20 points

Hi Guang,

I'm using it in a measurement circuit which depends on the output of your device a small change in the output will cause a large error that i'm measuring and I'll hook this p as you have mentioned and let you know whether it's getting overridden or not,thanks.

0 Guang Zhou over 5 years ago in reply to Jay Sashidharan

TI__Mastermind 32340 points

Hi Jay,

Sounds good, please do post back with your finds on this.

Regards, Guang

0 Guang Zhou over 5 years ago in reply to Guang Zhou

TI__Mastermind 32340 points

Hi Jay,

Want to check if there is any update, whether your issue has been resolved?

Regards, Guang

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LMP8645: Voltage at input terminals