ESP32 Forum

We would like to run ESP32 modules on a 2.4-2.7V supply.

The ESP32 data sheet's pin list mentions that the chip itself can work down to 2.3V, the Espressif website claims 2.2V in the chip overview, and a post by John Lee here earlier suggested it was actually down to 2.0V. However, the data sheet's table 8 in section 5.2 specifies a minimum of 2.8V for "V_BAT".

However, that is the only mention of "V_BAT" or even the word "Battery" in the whole spec sheet. So we are not sure what it refers to. Is it the input for the internal VDD_SDIO LDO? If so, is it saying that the dropout on the LDO is 1V, so a minimum of 2.8V needs to be supplied for it to provide 1.8V to the flash?

What it comes down to is simply: Given an ESP32 module with a 1.8V flash chip, what's the lowest supply voltage for which the module will work?

Anyone? Bueller?

Did you try out various voltages and get an answer for this?

No, it's not something we'd be comfortable making assumptions on based on tests across a small sample. We ended up not using the ESP32 in the end.

FWIW, the V_BAT spec is missing in the current data sheet, so I think it may have been a holdover from the ESP31 days. As far as I know, 2.3V is the actual minimum, although I wouldn't be surprised if there's a 0.3V safety margin and the ESP32 will work on 2.0V in normal environmental circumstances as well. (Do mind that the attached flash chip is also important: its specs usually are more narrow than that of the ESP32.)