Part Number:TPS659037
Hi,
we are working on a design with the TPS659037x PMIC and AM5728 and the question is about whether we can use POWERHOLD to turn on/off the system.
The AM5728 has an errata i862 where it needs a PORZ to have a reliable reset. The workaround describes the use of POWERHOLD.
Implementation 1: PMIC asserts porz when rstoutn is connected to PMIC
NRESWARM input
• When the rstoutn output from the SoC is connected to the external PMIC's
NRESWARM input, the PMIC companion device approved for use with the SoC can
be configured to detect the rstoutn/NRESWARM assertion and assert
porz/RESET_OUT. All PMIC companion devices which have been approved for the
SoC implement this feature. The feature is bootstrap selectable via one of the PMIC's
BOOT pin(s). Refer to PMIC User Guide for additional details. Note: This
implementation option has no added cost to the customer since the SoC must be
used with one of the approved PMIC devices.
• To implement the workaround:
– Connect the rstoutn output from the SoC to the PMIC's NRESWARM input (and to
any other components that need to reset when the SoC undergoes a reset). Note:
When the rstoutn output is operating in 3.3V mode, a 3.3 volt to 1.8 volt level
translator will be required to level shift the rstoutn output connected to the PMIC’s
NRESWARM input to 1.8 volts.
– Pull-up the appropriate PMIC BOOTx pin, to configure the PMIC’s RESET_OUT
to assert porz on warm reset.
– The PMIC’s POWERHOLD (GPIO7) input must be pulled high.
• Example use cases for this implementation include:
– A switch connected to the PMIC’s POWERHOLD input is used to turn the board
on/off.
Does POWERHOLD cause a reliable RESET_OUT signal and reliable Power Up and Down Sequences?
Is the below block diagram a sound solution for using POWERHOLD as on/off mechanism?
Thanks,
--Gunter