Recommended LFXO 32.768 kHz crystal oscillators

[Karlis]

Hi,

Do You have a recommended LFXO 32.768 kHz crystal oscillators parts list ?

Best regards

[Stian Røed Hafskjold]

Hi, we do not recommend any specific brand, but anyone that matches the spec in the reference layout should be fine.

X2

32.768 kHz

XTAL SMD 2012, 32.768 kHz, CI=9 pF, ±50 ppm

XTAL_2012

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/ref_circuitry.html?cp=4_2_0_52#concept_aqp_fd1_fq

[Karlis]

Hi, I found more detailed spec here : https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/clock.html?cp=4_2_0_18_3_3#unique_1385509760

There are mainly mentioned only max values. About frequency tolerance all is more or less clear.

But do You have recommended values for following parameters (or at least min. value):

Symbol	Description				Min.	Typ.	Max.	Units
CL_LFXO	Load capacitance						12.5	pF
C0_LFXO	Shunt capacitance						2	pF
RS_LFXO	Equivalent series resistance						100	kohm
PD_LFXO	Drive level						1	uW

As for drive level to be on safe side it looks like that there is only one option - 1uW

[ketiljo]

It's as simple as you have to make sure you don't exceed the maximum values.

For the drive level, the maximum level the oscillator can drive the crystal is 1 µW. So the crystal must be able to handle at least this.