ZHCSFH8D August 2016 – January 2018 TPS25741 , TPS25741A
UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
The VAUX pin is the output of a linear regulator and the input supply for internal power management circuitry. The VAUX regulator draws power from VDD after establishing a USB Power Delivery contract unless it is not available in which case it draws from VPWR. Changes in supply voltages will result in seamless switching between supplies.
If there is a load on the DVDD pin, that current will be drawn from the VPWR pin unless the TPS25741/TPS25741A has stabilized into a USB Power Delivery contract or VPWR is below its UVLO.
The TPS25741/TPS25741A cannot function properly until VPWR is above its UVLO. However, for improved system efficiency when UFP is high-z, VPWR can be low (the high voltage power supply can be disabled) if VDD is above its UVLO.
Connect a 0.1-µF ceramic capacitor from VAUX to GND. Do not connect any external load that draws more than IVAUXEXT. Locate the bypass capacitor close to the pin and provide a low impedance ground connection from the capacitor to the ground plane.
VDD should either be grounded or be fed by a low impedance path and have input bypass capacitance. Locate the bypass capacitors close to the VDD and VPWR pins and provide a low impedance ground connection from the capacitor to the ground plane.