MKL26Z64VFT4 (Teensy LC) Chip Need Loading Capacitors For Crystal??

[Noah517]

Hey all, I'm working on a project that uses the MKL26Z64VFT4 (Teensy LC) chip on a custom PCB.

I noticed that on the Teensy LC schematic, there is no loading capacitors for the 16 mHz crystal. After looking at the datasheet, I see that there are internal capacitors, but they are only recommended for low frequency 32 kHz crystals. The section of datasheet is below.



Do I need loading capacitors? My PCB Layout is below.

 

[jonr]

With the right crystal, the teensy LC schematic is correct. Do connect your XGND to the other grounds.

 

[Noah517]

With the right crystal, the teensy LC schematic is correct. Do connect your X ground to the other grounds.

What do you mean with the right crystal? Would some work and others not? About the ground being connected to other grounds, the PJRC website says, "The crystal should be located close to the MK20 chip. A ground plane should be placed underneath the crystal. If using a 2 layer PCB design, the ground plane for the crystal should NOT make any other connections to ground, other than the crystal case ground, capacitor grounds (if adding extra capacitance) and to the ground pin next to the crystal pins"

 

[jonr]

You can search this forum for crystals that are known to work - without capacitors. I'd guess that that discussion of ground plane is referring only to another layer, under the crystal. Again, follow the teensy schematic (which has Vss pin 23 connected to the other Vss pins).