JAJSTW1 August 2024 TPS55287-Q1
PRODUCTION DATA
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There are two ways to set the output voltage: changing the feedback ratio and changing the reference voltage. The TPS55287-Q1 has a 11-bit DAC to program the reference voltage from 45mV to 1.2V. The TPS55287-Q1 also can select an internal feedback resistor divider or an external resistor divider by setting the FB bit in register 04h. When the FB bit is set to 0, the output voltage feedback ratio is set in internal register 04h. When the FB bit is set to 1, the output voltage feedback ratio is set by an external resistor divider.
When using internal output voltage feedback settings, there are four feedback ratios programmable by writing the INTFB[1:0] bits of register 04h. With this function, the TPS55287-Q1 can limit the maximum output voltage to different values. In addition, the minimum step of the output voltage change is also programmed to 10mV, 7.5mV, 5mV, and 2.5mV, accordingly.
When using an external output voltage feedback resistor divider as shown in Figure 6-5, use Equation 5 to calculate the output voltage with the reference voltage at the FB/INT pin.
TI recommends using 100kΩ for the up resistor RFB_UP. The reference voltage VREF at the FB/INT pin is programmable from 45mV to 1.2V by writing a 11-bit data into register 00h and 01h.