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).

[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

[Hamilton DC]

Hi @Aagra.1​ ,

In the datasheet, Search for FERR_L, HSE32 crystal requirements, HSE32 TCXO regulator characteristics for more information. Concerning the question about frequency drift, please, see my answer below. Do not confuse frequency drift with FERR_L. It's not the same thing. The frequency drift occurs during a packet transmission when the frequency of Tx drifts due to heat (from the device) propagation reaching the crystal. The heat generation is related to the RF output power.

[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.

[frnt]

Dear @Hamilton DC​ ,

since the NT2016SF-32M-END5875A cannot be found from distributors (even the datasheet is not available).

Could you provide the specs of such device (pin capacitance, frequency stability, power supply, etc...)

or at least provide an alternative component?

Even the application note AN5042 doesn't give information either the datasheet of the STM32WL55XX (pag. 99): https://www.st.com/resource/en/datasheet/stm32wl55jc.pdf

Here, only the requirements for the HSE are present but not for the VCTXCO.

Can you give this information for making a custom board?

For example, could the TXEABDSANF-32.000000 be used in place of the NT2016SF-32M-END5875A?

Here the datasheet: https://www.taitien.com/wp-content/uploads/2015/12/XO-0076_TX.pdf

Thanks a lot

[AElgh]

Any update on this topic?

[mardaguler]

Any update for NT2016SF-32M-END5875A ?