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TPS6594-Q1: TPS6594 and LP8764 power on issues.

Carlos Barreiro
Prodigy 20 points
Part Number: TPS6594-Q1
Other Parts Discussed in Thread: DRA821U

Tool/software:

Hi,

I have a custom board with a DRA821U with PDN implemented as per slvuby7a.

Mounted devices on board are TPS6594141BRWERQ1 and LP876441B1RQKRQ1.

VSYS_SENSE and OVPGDRV have the expected behaviour and VCCA/VIO_IN are supplied to both PMICS.

TPS6594 VOUT_LDOVINT and VOUT_LDOVRTC measure 1V8 and LP8764 VOUT_LDO also measures 1V8 on VOUT_LDO.

Crystal on TPS6594 is oscillating, measured 32.76KHz on OSC32KOUT.

LP8764 ENABLE is sourced from TPS6594 VOUT_LDOVINT and TPS6594 ENABLE is pulled up to VCCA.

However none of the output voltages, neither GPIO are sequencing.

Measured residual voltages on all the outputs, all of them under 50mV.

I have ordered a TPS6594 EVK in order to be able to acess the I2C of the PMICs, but i would like to know if there are any other test that could be performed on the board.

Thanks!

 

  • 0
    TI__Guru* 78171 points

    Hi Carlos,

    A readout by I2C would be a good step when you get the EVM available. Can you capture a waveform of the VCCA and VIO_IN and other signals to show what is happening? How does the ON REQUEST to the enable pin look? Have you ensured Watchdog Disable is configured correctly with the GPIO_8?

    Regards,

    Katie