The TPS546C25 device offers true differential remote sense function which is implemented between VOSNS pin and GOSNS pin. The output of the differential remote sense amplifier is internally fed into the control loop and doe not come out to a package pin.

Differential remote sense function compensates a potential voltage drop on the PCB traces thus helps maintain VOUT accuracy under steady state operation and load transient event. Connecting the VOSNS pin and GOSNS pin to the remote location allows sensing the output voltage at a remote location. The connections from VOSNS pin and GOSNS pin to the remote location must be a pair of PCB traces with at least 12 mil trace width, and must implement Kelvin sensing across a high bypass capacitor of 0.1μF or higher. The ground connection of the remote sensing signal must be connected to GOSNS pin. The VOUT connection of the remote sensing signal must be connected to VOSNS pin. To maintain stable output voltage and minimize the ripple, the pair of remote sensing lines must stay away from any noise sources such as inductor and SW node, or high frequency clock lines. TI recommends to shield the pair of remote sensing lines with ground planes above and below.

The recommended GOSNS operating range (refer to AGND pin) is −300mV to +300mV. In case of local sense (no remote sensing), short GOSNS pin to AGND.

The TPS546C25 offers two methods for determining the converter output voltage: a fully integrated, internal, precision feedback divider or an external feedback divider. The method used is determined by the selection made on the MSEL1 pin (see Pinstrapping for details). Using the external feedback divider, the output voltage is programmed with an external resistor divider from the output (VOSNS connection) to ground return (GOSNS) with the center point connected to the FB/VSEL pin. TI recommends to use 1% tolerance or better divider resistors. Starting with a fixed value for the bottom resistor, typically 10kOhm, use the equation to calculate the top resistor in the divider.

Where VREF is the internal reference DAC voltage programmed in VBOOT_NVM by default, which is 0.4V.

If MSEL1 is set to use the internal feedback divider, a resistor from VSEL/FB to AGND selects the output voltage setting (see Set Output Voltage for more details).