I am using a TPS43320 to regulate 12V to 3.3V, and was wondering what the effect of an invalid RMODE resistor is? I just noticed we are using 11.8kΩ for our RMODE, but that isn't a value in the table. Rather, 11.3kΩ is instead.
Would this cause irregular behavior or anything of the sort?
Hi Dylan,
We still recommend to use accurate 11.3k resistor with 1% or less tolerance for mode pin detection even if 11.8k works.
Generally 11.8k would be detected as 11.3k since the next gear is 14.3k.
The mode detection is realized by forcing a fixed current on the resistor during powering up and detect the voltage using a DAC to figure out which mode is chosen.
Hi Dylan,
The wrong resistor value would influence the mode selection including current limitation, ramp compensation and soft-start time.
For example, if you use a 13k for 11.3k and be detected as 14.3k gear, the soft-start time would be changed from 1ms to 2ms.
If using a wrong resistor, the device would at least choose a adjacent mode. There couldn't be any serious effect that the device damage or couldn't start up.
