Together with the selected range, the VSET[7:0] bits in the VSET register control the output voltage setpoint of the device (see Table 9-4).
|VRANGE[1:0]||Output Voltage Setpoint|
|0b00||0.4 V + VSET[7:0] × 1.25 mV|
|0b01||0.4 V + VSET[7:0] × 2.5 mV|
|0b10||0.4 V + VSET[7:0] × 5 mV|
|0b11||0.8 V + VSET[7:0] × 10 mV|
During initialization, the device reads the state of the VSEL pin and selects the default output voltage according to Table 9-5. Note that the VSEL pin also selects the I2C target address of the device (see Table 9-10).
|VSEL Pin(1)||Device Number||VSET[7:0]||Output Voltage Setpoint|
|6.2 kΩ to GND||TPS6287x-Q1||0x5a||850 mV|
|Short-Circuit to GND||All||0x46||750 mV|
|Short-Circuit to VIN||All||0x5f||875 mV|
|47 kΩ to VIN||TPS6287x-Q1||0x78||1.0 V|
If the user programs new output voltage setpoint (VOUT[7:0]), output voltage range (VRANGE[1:0]), or soft-start time (SSTIME[1:0]) settings when the device has already begun its soft-start sequence, the device ignores the new values until the soft-start sequence is complete. If the user changes the value of VSET[7:0] during soft start, the device first ramps to the value that VSET[7:0] had when the soft-start sequence began. Then, when soft start is complete, ramps up or down to the new value.
If the user changes VOUT[7:0], VRAMP[1:0], or SSTIME[1:0] while EN is low, the device uses the new values the next time the user enables it.
During start-up, the output voltage ramps up to the target value set by the VSEL pin before ramping up or down to any new value programmed to the device over the I2C interface.