Recommended NT2016SF-32M-END5875A for STM32WL design

[Martin.Sergio]

We design a new product where we use STM32WL microcontroller and in the datasheet ST is recommended to use NT2016SF-32M-END5875A

manufactured by NDK but we dont found it to buy.

Can you provide some distributors where we can buy this TCXO?

Can you provide other alternative TCXO to NT2016SF-32M-END5875A?

Thanks a lot and best regards

[DedMoroz]

Did consider to use a regular 32Mhz HSE?

[Martin.Sergio]

No, we have not considered using a a regular 32Mhz HSE because temperature variations will be constant, not only because the equipment will be outdoors, but also because the RF circuit produces temperature increases.

[Hamilton DC]

Note that there is a global shortage of TCXO due to a fire at an Asahi Kasei Microdevices (AKM) factory in Japan. 

[DedMoroz]

We designed a prototype with WLE5 without TCXO. The RF part not tuned at all and we got only 20m distance inside the building with 4db output, but I look forward for a better results. We also consider to change SUBGHZ_HSEOUTTRIMR values dynamically based on the outside temperature to keep the crystal tuned.

[Hamilton DC]

If you're designing LoRa applications, then the recommendation is:

For high power applications (RFO_HP), use a TCXO instead of XO (crystal) as HSE clock source due to frequency drift issues.

For low power applications (RFO_LP), you can use an XO as HSE clock source with a thermal barrier on the PCB (no metal around the XO to reduce thermal conduction).

[FZ_]

We have encounter the same problem. Could someone from ST, recommend ano other VCTXCO to replace NT2016SF-32M-END5875A which is used in the EVB Nucleo. In our project as well, the temperature variation is very important. Using a regular 32MHz HSE, is not the best option.

Could this product be used as an alternative:

https://www.iqdfrequencyproducts.com/products/details/iqxt-205-2-1-01.pdf

Thanks.

[phoenixSun35]

@DedMoroz​ Try without XTAL caps. I have suffered for one week to recognise it.

[Aagra.11]

Hi Hamilton,

thanks for your reply. Can you help me understand how much drift can be there if i used normal crystal? also i want to understand the maximum allowed PPM for the crystal in tolerance and stability for STM32WL. I have gone through the AN2867 , but it does not give me these questions answers.

My application will be outdoor and 22DBM module with 865MHz (Indian) frequency band.

kindly help.

regards

Ankush Agrawal

[Rvan .8]

When designing for a LoRa application with low-power (RFO_LP) only, should the TCXO external HSE clock then be omitted completely? Or should the TCXO and XO back-up both use the XO as HSE? (i.e. just use the same crystal, NX2016SA-32MHz, for both)