SN99057

The TI SN99057RSBR is a power management IC used by the Vita in conjunction with the bq27520-G1 battery fuel gauge to manage the battery. There is a USB interface that is connected to a switch TS3USB31RSER with the main Kermit USB. When the device is powered off and connected to a PC, this chip is likely what the USB sees. TI has stated that “the SN99057RSBR part was a custom device manufactured for a specific company.”

The device is now obsolete nor do we have access to the datasheet.

The current hypothesis is that this IC is responsible to managing battery charging.