MP2731 OTP registers


My question is regarding the OTP registers in MP2731.
I could not find any comprehensive text description of the behavior of these registers.

Are they true OTP - i.e. when set they cannot be written to and changed again ever?
Or are they semi-OTP - i.e. when a REGISTER RESET is sent, all registers are set to POR and new user values can be written to all R/W registers - including the OTP defined ones?

What happens if all power is removed, both battery and input power supply? Will the OTP registers keep their user set values?

A truth table clearly describing the registers behavior at all different conditions would be appreciated. Conditions like: Vin power cycling (Vin POR?), All power (Vin and battery) off/on, REG_RST, System reset DICS pin and WDT reset and etc.


Regards HC

Hello HC,

MPS devices stated as OTP are true OTP. Once they are set, they can not be changed regardless of power status or conditions.

Devices that are referred to MTP or multi-time programming are what you referring to as semi-OTP.

Thank you,
Vinh Tran
Field Applications Engineer

Hello Tran,

I just purchased the dev kit. I can see that this has a GUI for setting the registers.

Thanks for confirming that I can set the charging current, as an example, just ones, from the GUI. So, this means that I cannot “play” with most register settings when evaluating your device, as I understand it. I must say this is a little bit odd. Imagine I have multiple products with different batteries, do I also need multiple dev kits then, for testing each type of battery?



Using the GUI, I changed the Vin_min to 4.4V from default 4.3V.
Then I removed power. It still came back to default 4.3V when power was reinserted.
I was under the impression that the first time I wrote a value to this register, that the value would be retained.

How does the OTP work?