Introduction: Mod a USB to TTL Serial Adapter (CP2102) to Program ESP8266

Picture of Mod a USB to TTL Serial Adapter (CP2102) to Program ESP8266

This USB to TTL Serial board based on the CP2102 chip, it have no enough current (400mA+) to driven ESP8266. So I will fix the issue.

CP2102 Datasheet:

UPDATE: I made a new CP2102 USB to TTL converter depend on the board. It's now on tindie.

Step 1: Materials

Picture of Materials

  • 1 x CP2102 USB adapter, it's easy be found at eBay by keyword cp2102
  • 1 x AMS1117-3.3
  • A knife
  • A soldering iron

Step 2: Cutting Off the Original 3.3V Output

Picture of Cutting Off the Original 3.3V Output

The 3.3V from CP2102 has only 200mA output. It's not enough for esp8266. I cutting off the 3.3V output with an knife.

Step 3: Soldering LDO AMS1117-3.3

Picture of Soldering LDO AMS1117-3.3

Use the pin 5V as input of AMS1117, connect the output to 3.3V

Now the USB adapter can driven esp8266 directly.


adam_99 (author)2016-04-19

Will it work on PL2303HX chip as well?

kubik256 (author)adam_992017-04-13

I'm using old Profilic PL2303 USB2TTL adapter with dual 3.3V and 5V outputs.
On 3.3V pin flashing ESP without external power is ok ;) Tested with ESP-01, ESP-12E, ESP-14 and LUA MCU Dev Board V3.

If you have only 5V output, so this mod can work. BR

adam_99 (author)kubik2562017-04-13

I didn't know I can draw enough current from the chip on 3.3v
I'll try.

ShahariaS (author)adam_992016-06-08

did you find the ans ??

adam_99 (author)ShahariaS2016-06-17

No :(

ShahariaS (author)adam_992016-06-08

did you find the ans ??

ShahariaS (author)adam_992016-06-08

did you find the ans ??

ShahariaS (author)adam_992016-06-08

did you find the ans ??

DerMega (author)2015-08-19

Hmmm aren´t the TR/RX wires from the CP2102 5V too?

So they are able to destroy the ESP aren´t they?

JoelM5 (author)2015-05-08

Can I use cp2102 to convert TTL to USB?

yanc (author)JoelM52015-05-08


kapilrathi22 (author)2015-02-21

I am using ESP8266 with CP2102. For ESP8266 supply I am using LD33v connected to VCC and CH_PD. as soon as serial monitor is open it shows continuous garbage value which is never ending. How to solve this issue?

yanc (author)kapilrathi222015-02-21

Is the VCC 5V output from USB port?

kapilrathi22 (author)yanc2015-02-23

Hi yanc, For ESP supply I used LD33v output which is 3.3 v and can handle 1A current.

yanc (author)2015-01-31

You can found the driver here

yanc (author)2015-01-31

Hello, please search ebay for cp2102, you will find a lots of board like the image.

e024576 (author)2015-01-31

Really great Project ! Two questions: I have a hard time finding the same board on ebay, that is: 3.3v, 5 pins, CP2102. Any hints where to get it?

Also, what about CP2102 Windows 7 driver - can you recommend best source?

Thanks Paul