LP2985: 3.3V is not going down to zero, even when the shut down pin is connected to a low pulse

Sandeep NS

Part Number: LP2985
Other Parts Discussed in Thread: ADS131E06

Hi,

I want to control the 3.3V output with the help of ON/OFF pin.

So i have use below circuit. Transistor BC817

Vin -12 V, Vout =3.3V

But i am getting below waveform

3.3 is not touching 0V . What can be the issue of this

Thanks and regards

Sandeep

0 Sandeep NS over 3 years ago

0 Jason Song over 3 years ago in reply to Sandeep NS

Hi Sandeep,

What do you have on the output side? The voltage on the output pin when the LDO is off could be due to the leakage that pulls up the output pin.

Regards,
Jason Song

0 Sandeep NS over 3 years ago in reply to Jason Song

LDO output is connected to TI ADC ADS131E06 and to the crystal oscillator

Thanks and regards

Sandeep

0 Jason Song over 3 years ago in reply to Sandeep NS

Hi Sandeep,

To confirm the issue, will you completely remove any load on the output side and see if you have the correct voltage on the output side?

Regards,
Jason

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