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Recommended NT2016SF-32M-END5875A for STM32WL design

Associate III

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


@Hamilton DC​ 

Hi @Rvan .8​ ,

If the thermal barrier is sufficient to prevent the frequency drift, then the tcxo is not mandatory for LoRa applications.

It's not simple to say whether a thermal barrier is sufficient or not because it depends on PCB materials etc.

What can be done is to use a "hybrid" footprint. This means a compatible footprint with a crystal and a TCXO. If with a crystal you pass the constraints in terms of frequency drift, then you populate the rest of your PCBs with only the crystal as the source of the HSE oscillator. See an example below:


You should pay attention to the fact that your application might work in a wide range of ambient temperature. In this case, your application with a crystal instead of TCXO should keep the frequency drift below the specifications.

The LoRa specifications are:

LowDataRateOptimize set to 0x00: +- 40.69 hertz (between t_start =0s and t_stop = 700 milliseconds)

LowDataRateOptimize set to 0x01 (SF11 and SF12 only): +- 162.76 hertz (between t_start =0s and t_stop = 2000 milliseconds)

You must keep the frequency drift in the range above during the time t_start and t_stop.

To do this measurement you need a spectrum analyzer with an Analog Demod (FM) option to track the drift of RF carrier at t_start and t_stop depending on the configuration above.

To see an example of thermal barrier that passes the LoRa constraints in terms of frequency drift, go to:

On the link above search for: "HW design models".

And then: "STM32WL RefBoards release" (Version 1, 27 Jan 2021)

The file contains the Altium project of the STM32WL (QFN-48 package) Reference Design with a thermal barrier that passes the LoRa constraints in terms of frequency drift.

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.

Thank you very much! @Hamilton DC​ 


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):

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:

Thanks a lot

Associate III

Any update on this topic?