IO voltage pins

Lars R.
Posts: 13
Joined: Thu Oct 30, 2014 8:05 pm

IO voltage pins

Postby Lars R. » Sat Nov 08, 2014 1:22 am

Hi,

Specification states:
VDDIO(min): 1.7V
VDDIO(max): 3.6V
Thus, I assume, IOs can operate at 1.8V, 2.5V and 3.3V in dependece of VDDIO, which is great.

Reference schematic states:
IO_VDD=VDDPST
There are two VDDPST pins on the package. On on the bottom and one one right hand side.
Are those VDDPST pins assigned to different banks/IO-pins? If so, which power-pin is assigned to which IO-pin?
E.g, could the SPI be driven with 1.8V low-voltage flash, while the other IOs are 3.3V?

thx and regards
Lars

Edit: Replaced "left hand side" by "right hand side"

Espressif_Kelly
Posts: 140
Joined: Mon Oct 27, 2014 10:40 am

Re: IO voltage pins

Postby Espressif_Kelly » Fri Nov 14, 2014 3:08 pm

Dear Sir,

Thank you for your questions.

Both two VDDPST are digital and IO power supply and the source is the same.The reason for using two VDDPST is to prevent the possible insufficient power supply current.

The recommended voltage of VDDPST is 3.3V.

Any more questions, please feel free to contact us.

Thanks.

guan
Posts: 17
Joined: Wed Oct 29, 2014 8:41 am

Re: IO voltage pins

Postby guan » Sun Nov 23, 2014 11:23 am

Does this mean that if I want to run on 2 AA batteries (NiMH), we should have a boost converter to 3.3V? It would be nice to know more about the range of possible values for the ESP8266 itself.

Espressif_Kelly
Posts: 140
Joined: Mon Oct 27, 2014 10:40 am

Re: IO voltage pins

Postby Espressif_Kelly » Mon Nov 24, 2014 1:00 pm

Hi,

Digital and IO Power Supply(Pin 11, Pin 17): 1.8V ~ 3.3V

Analog and PA Power Supply(Pin 1, Pin 3, Pin 4, Pin 29, Pin 30):3.0V ~ 3.6V.

Voltage of 2 AA batteries is ok.

Anki
Posts: 25
Joined: Thu Apr 09, 2015 3:00 am

Re: IO voltage pins

Postby Anki » Thu Apr 23, 2015 7:26 am

Can anyone confirm that the ESP8266EX will run stably with VDDPST supplied by a 1.8V regulator and VDDA, VDDD and VDD3P3 supplied from a 3.3V regulator (assuming sufficient decoupling capacitors of course)? Thank you.

Espressif_Kelly
Posts: 140
Joined: Mon Oct 27, 2014 10:40 am

Re: IO voltage pins

Postby Espressif_Kelly » Wed Jun 03, 2015 8:43 pm

Dear Anki,

ESP8266EX can work ok with VDDPST supplied by a 1.8V regulator and VDDA, VDDD and VDD3P3 supplied from a 3.3V regulator.

Notes:

1.CHIP_EN of ESP8266EX should be better to be pulled up to 3.3V.

2.Pay attention to the power supply of external spi flash. Most common-used spi flash do not support 1.8V power supply.

Thanks.

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