MP2723A OTP field isn't OTP

Battery Management
1

The charge timer field (bits 1,2) within the MP2723A timer configuration register (0x08) is supposed to be a one-time programmable field. However, I’m observing that if I change the value of that field (verified with a read-back) and then power cycle the chip, the field resets to its default value. Is this an erratum or am I missing a step somewhere?

1 Like
2

Hello,

The MP2723A is OTP not MTP. It can be flexibly configured through I2C while powered-on, but these settings are not physically burned into the registers so they will be restored to default values when power cycled.

Best,
Luke

3

Thanks for the response. I think I’m still misunderstanding though. If the OTP registers are restored to default values when power cycled, what makes them one-time programmable? How are they different than any other register?

4

Hi,

‘One-time programmable’ refers to the register configuration that is programmed at the factory. MTP parts can be reprogrammed, and these settings will become default values when power cycled. OTP has a single register page so once the configuration is burned it can no longer be changed, while MTP has multiple (but limited) register pages so new configurations can be used.

Luke

5

Hmm I just found this old thread. So you guys should start making MTP / FTP chips because this is super unclear that the OTP settings are ‘factory order’ options really, not OTP by the customer.

For our project on the MPS2672A, the default settings will fry the batteries instantly.