nrf52 high speed crystal oscillator selection considerations

[Najam]

Hi everyone,

We are designing boards using the nrf52832 microcontroller and using the nrf52dk as a design reference. 
In the BOM for the nef52dk board we noted HS crystal oscillator used is with part number "Q22FA1280002512", this is 32 MHz crystal with 60 Ohms impedance and 100uW drive current requirement, the temperature range for this part is from -20 to 75 degrees Centigrade.

We wanted to use parts in range for -40 to 85 degrees Centigrade, after search we found part number "XRCGB32M000F1H01R0" from Murata. Everything is the same with reference crystal but issue is that the drive current requirement is 300uW. We wanted to ask if this crystal will work with nrf52832, if yes then what effect will be on the current consumption of the SoC. Will there be any other effect on the SoC with regards to service life, etc.?

Regards,

Najam us Saqib

[ketiljo]

The two crystals you refer to should have equal performance. The CL value is important for the current draw and startup time. 8 pF is ok here. 

The 300 µW is max drive level the crystal can handle. As long  as this number is higher than the drive level of the oscillator, 100 µW, you're good. The XRCGB32M000F1H01R0 part should be a direct replacement. 

[Najam]

Hello again,

These days we could not find the parts which we wanted to use in our original design.

Can we use FA-128 32.0000MF20X-AJ as replacement?
It has the following characteristics
1. Tolerance: ±10 PPM
2. Stability: ±20 PPM
3. Temperature: -20 to 75 Degrees
4. Impedance: 60 Ohms
5. Load Capacitance: 8 pF

I am concerned by the frequency stability parameter.

The Crystal Spec by nordic specifies ±40 PPM tolerance, so we will calculate this like (±20 + ±10) = ±30 PPM for total tolerance?

Thanks in advance.