LP5024: power on

Shreenidhi Patil

Expert 4156 points

Part Number: LP5024

We are facing problem in working of LP5024 IC.

IC is not switching ON when being powered up from a valid Vcc of 3.3V

VCAP voltage is 0V

When we check Pin 31, we are getting 1.8V LDO output which is in contrast to datasheet which says pin 32 is 1.8V LDO.

Can you please let us know if are missing something .

Also find attached Schematic ..

Please let us know how we can resolve this issue.

over 6 years ago

0 Kenneth Du over 6 years ago

TI__Genius 14295 points

Hi, Shreenidhi,

Based on the schematic, PIN 32(VCAP) should be 1.8V, and PIN31(IREF) should be 0V.

Can you verify the test again? Or any open/short for these two PINs?

0 Kushagra Mittal over 6 years ago in reply to Kenneth Du

Prodigy 30 points

Kenneth Du said:
Hi, Shreenidhi,

Based on the schematic, PIN 32(VCAP) should be 1.8V, and PIN31(IREF) should be 0V.

Can you verify the test again? Or any open/short for these two PINs?

Hi Kenneth,

We have verified the shorting and open condition of the pins. It is okay. Also in practical condition, PIN 31 is behaving like VCAP and PIN 32 is behaving like IREF. In this configuration, IC is switching ON and I2C communication is also OK.

Also this configuration is against the datasheet. Could you please help to know the issue.

Regards,

Kushagra

0 Kenneth Du over 6 years ago in reply to Kushagra Mittal

TI__Genius 14295 points

You mentioned the IC is working normally?

This is quite strange, and can you double check the chip on LP5024EVM?

0 Kushagra Mittal over 6 years ago in reply to Kenneth Du

Prodigy 30 points

Hi Kenneth, IC on EVM is PLP5024T TI878AG58.This IC is functioning okay and all readings are as per data sheet.

We are using IC LP5024 TI878AG54 which we also received from TI samples directly. In this IC we are facing problem of 1.8V at Iref pin, I2C working ok and register is being set. Current sink is not working. Also in addition to this, Enable pin is pull up to 3.3V with 4.7K resistance where voltage is dropping by 0.3V which looks quite weird.