ESP32 External RTC crystal Component Selection

dovov97815
Posts: 19
Joined: Mon Aug 17, 2020 10:24 am

ESP32 External RTC crystal Component Selection

Postby dovov97815 » Thu Dec 01, 2022 8:26 am

Hello,
I am working on the Project in which I am using ESP32 WROOM 32E and this Project will be Battery Operated.

So my question is regarding using of External Crystal (RTC) and for that as per the Datasheet i have made connections of Crystal Oscillator and its Components.

As you can see in attached image;
1) You have given the Resistor value in the Range of 5M ohm to 10M ohm. So If I get 5M ohm then what will be the Impact on performance of Crystal and same question for 10M ohm Value.
2) Can you suggest us the Crystals and its Capacitor values?
3) Suggest the Value of R3 and R5 Resistors.
image.png
image.png (113.92 KiB) Viewed 1243 times

ESP_LJH
Posts: 384
Joined: Tue May 18, 2021 9:21 am

Re: ESP32 External RTC crystal Component Selection

Postby ESP_LJH » Fri Dec 02, 2022 6:18 am

Basically, we tested that using impedance values among 5M and 10M will be helpful to activate crystal, but it is not easy to say impact difference between those values.
We commonly use SF32K32768D31T-12.5 and 12 pF as matching caps, you could consider those values as reference.
R3 and R5 could be 0.

dovov97815
Posts: 19
Joined: Mon Aug 17, 2020 10:24 am

Re: ESP32 External RTC crystal Component Selection

Postby dovov97815 » Mon Dec 05, 2022 6:22 am

Can we use ABS25-32.768KHZ-T ?
Which value for R4 is recommended? 5M or 10M?

Who is online

Users browsing this forum: No registered users and 54 guests