FA-238 XTAL?

[Jasper Speicher]

I have read the nAN24-13 application note as well as the crystal selection portion of the nRF24LE1 and nRF24LU1 data sheets and I am still undecided about this crystal

https://www.mouser.com/ProductDetail/Epson-Timing/FA-238-160000MB-K3?qs=sGAEpiMZZMsBj6bBr9Q9aXmxIa9b7yjIv%2fIGgGFQWuI%3d

I am planning to use it with c1=c2=14pF

Although the load capacitance and ESR look like they are in range, and it is not a tiny can, I am concerned about this note:

The start-up time is typically about 1 ms for a crystal with 9 pF load capacitance and an ESR specification Revision 1.6 121 of 196 of 60 Ω max. This value is valid for crystals in a 3.2×2.5 mm can.

Is this crystal a mistake? Will I get the required startup time?

Thank you,

J

[Andreas]

Hi,

 

Your crystal has slightly higher C_L, and the same can size as the note specifies start-up time for, so it should be a little higher, but within specificaitons. Still, you should measure the start-up time (instructions in this appnote) in your design and use a crystal with a lower C_L if needed, this will lower your current consumption as well.

 

Best regards,

Andreas