## ESP32-PICO-D4 Minimum Supply Voltage

aczento
Posts: 2
Joined: Wed Oct 30, 2019 9:27 am

### ESP32-PICO-D4 Minimum Supply Voltage

Hello there,

I am confused about the datasheet of the ESP32-PICO-D4.
https://www.espressif.com/sites/default ... eet_en.pdf

On page 10 it states a power supply voltage in the range of 3,0V to 3,6V.
But if you check the table on pages 3/4/5 all power supply pins are specified in the range of 2,3V to 3,6V.

So any ideas how this relates and which minimum supply voltage is the right one?

I am designing a battery powered product with 2x AA batteries. So it is crucial to know if I need an additional boost-converter or if I am free to go with the battery voltage directly.

Thanks and Regards
Alex

Espressif_Kelly
Posts: 8
Joined: Tue Nov 24, 2015 2:19 am

### Re: ESP32-PICO-D4 Minimum Supply Voltage

Dear Alex,

The voltage range of 2,3V to 3,6V listed in the datasheet is for each individual power supply pin. However, in actual application,we mostly use single power supply(VDD) and flash is connected to VDD_SDIO for low power consideration.

Operating voltage of the flash that integrated in ESP32-PICO-D4 is 2,7V to 3,6V. When VDD_SDIO operates at 3.3 V, it is driven directly by VDD3P3_RTC through a 6 Ω resistor(R), therefore, there will be some voltage drop from VDD3P3_RTC. It should comply with the following specifications:
VDD3P3_RTC > VDD_flash_min + I_flash_max*R
Among which, VDD_flash_min is the minimum operating voltage of the flash, and I_flash_max the maximum current.

Tests prove that VDD should be no less than 3,0V to ensure the normal work of internal flash.

As you have mentioned in your post, you want to use 2x AA batteries for power supply, it is recommended you to add an additional boost-converter for safe.

Any more questions, please feel free to let us know.

Thanks.

aczento
Posts: 2
Joined: Wed Oct 30, 2019 9:27 am

### Re: ESP32-PICO-D4 Minimum Supply Voltage

Hello Kelly,

thanks for quick and detailed reply!

Maybe you should consider adding this information to the datasheet or in the FAQ sections?

BR,
Alex

ESP_Alvin
Posts: 129
Joined: Thu May 17, 2018 2:26 am

### Re: ESP32-PICO-D4 Minimum Supply Voltage

Hi Alex,

Thanks for your suggestion. The Datasheet has been updated, please refer to the updated versions at

https://www.espressif.com/sites/default ... eet_cn.pdf
https://www.espressif.com/sites/default ... eet_en.pdf

Thanks.

Alvin
Best Regards