Michael OssmannMar 6

I've recently used insights from this article to implement a sample rate step size 128 times smaller than previously supported in HackRF:

https://www.pa3fwm.nl/technotes/tn42a-si5351-programming.html

This means that sample rates around 20 Msps can be adjusted in steps of about 0.015 Hz. The precision is even better at lower sample rates.

I highly recommend reading it if you use #Si5351 in any projects. #Si5351A #Si5351B #Si5351C

Understanding and enhancing Si5351 programming

Gary @N8DMTSep 22, 2025
@M0PWX … and set 1 of the 3 clock outputs to a frequency for easy external divide down to 1 PPS of the Si5351A 25 MHz clock, then phase compare and A/D (or just fast sample the go-high’s of the 1 PPS’s). Then adjust 25 MHz freq “definition” to lock-up. Might be fun but a ways down on the projects list due to not needing super accuracy at the moment. Have you seen anyone who has done this with the Si5351A? See them in a LOT of projects these days… Thanks & 73
#HamRadio #TestEquipment #Si5351A
Show threadGary @N8DMTSep 22, 2025
Set up Digilent Analog Discovery 3 w/ Waveforms SW to monitor the Arduino UNO to Si5351A clock generator interactions. Will investigate the existing UNO’s programming with the Si5351A board and then create a LabVIEW VI to mimic that process using another I2C interface board. Once basic frequency set and error checks are working, can expand the functionality thereafter. Hoping that LabVIEW makes this board really easy to use as a programmable clock generator.
#HamRadio #TestEquipment #Si5351A
Fabián LU4EHFDec 29, 2024

vm.tiktok.com/ZMkBusnJq/

No se si te va a gustar.
Trabaja en 10KHz a 160MHz

#arduino #radio #ham #Si5351a

TikTok - Make Your Day

Fabián LU4EHFDec 29, 2024

vm.tiktok.com/ZMkBusnJq/

No se si te va a gustar

#arduino #radio #ham #Si5351a

TikTok - Make Your Day

Ed W8EMV Nov 22, 2022

@Bleijswijk

There's a data sheet for the #Si5351A and family here

https://www.skyworksinc.com/-/media/Skyworks/SL/documents/public/data-sheets/Si5351-B.pdf

Looks like there's a couple of related parts (A B C) in a few pinouts, and there's some additional application notes on the SkyWorks site with details of the I2C bus registers.

have fun!

Ed W8EMV Nov 22, 2022

@Bleijswijk neat! sounds like a fun project

That part looks very similar to this #Adafruit component

https://www.adafruit.com/product/2045

except for the blue vs red circuit board.

"The #Si5351A clock generator is an I2C controller clock generator. It uses the onboard precision clock to drive multiple PLL's and clock dividers using I2C instructions."

Looks like they have a tutorial too.

https://learn.adafruit.com/adafruit-si5351-clock-generator-breakout

Adafruit Si5351A Clock Generator Breakout Board - 8KHz to 160MHz

Never hunt around for another crystal again, with the Si5351A clock generator breakout from Adafruit! This chip has a precision 25MHz crystal reference and internal PLL and dividers so it ...