32MHz clock option in JN516x chips

[witoldsowa]

JN5168 (and other in the family) have quite strict requirements regarding 32MHz crystal to be used - low ESR or low capacitance. These can be achieved with large footprint crystals like 3.2x2.5mm crystal used in JN5168 Mxx modules or USB dongle. I am however very constrained in PCB space and I'd like to use smaller device instead, e.g. a silicon or crystal oscillator like this: http://docs-europe.electrocomponents.com/webdocs/12e7/0900766b812e7646.pdf . Datasheet says I can use external source for 32kHz clock but says nothing about other source than crystal for 32Mhz clock.

Can I use JN5168 with such devices instead of crystal? How do I connect it? Just directly to XTALIN and leave XTALOUT not connected?

[witoldsowa]

Thanks for the response. I’ve ended up with 2x1.6 mm crystal from Epson: Q22FA1280002511 | Crystal 32MHz, ±10ppm, 4-Pin SMD, 2 x 1.6 x 0.5mm | Epson 

It is 8pF and 60Ω so with 13pF capacitors works fine within JN5168 specs. 

Regards,

Witek. 

[mario_castaneda]

Hi Witold,

Can I use JN5168 with such devices instead of crystal?

We only recommend 32MHz crystal to be used. The clock generated by this oscillator provides the reference for most of the JN516x subsystems, including the transceiver, processor, memory and digital and analogue peripherals. 

Best Regards,

Mario