We currently utilize the MP8860 in one of our designs. We now have an application that requires a higher output current than the 1A rating of the MP8860 device. While the MP8862 seems like the logical replacement device, it is not in stock anywhere. Therefore, I am looking at the MP28167-A device. I would like to configure the MP28167-A device to have the same 10mV Vout resolution as the MP8860 device. This can be achieved with the following feedback resistors R1 = 115k and R2 = 10k. The series resistance of these resistors, however, is much lower than any of the resistor suggestions in Table 1 on page 28 of the datasheet. Besides the extra current flowing from Vout to GND, are there any other downsides to using these lower ohm feedback resistors values? If R1 = 115k and R2 = 10k are acceptable, do you have a recommendation for the Rt resistor value?
We are actively using the I2C interface to adjust the output voltage between 2.5V and 20V. Therefore, the default Vout value generated by the Vref register and the feedback resistors on initial power-up is not critical for us. We will overwrite the Vref register with our designed value via I2C.
Thanks for your assistance -