New here, just to ask about K82 crystal oscillator capacitors.

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

New here, just to ask about K82 crystal oscillator capacitors.

414 Views
georgekrasle
Contributor I

In the reference manual,
https://www.nxp.com/docs/en/reference-manual/K82P121M150SF5RM.pdf 

section 30.9.2.4:

In high-frequency, low-power mode, the oscillator uses a gain control loop to minimize power consumption. As the oscillation amplitude increases, the amplifier current is reduced. This continues until a desired amplitude is achieved at steady-state. In this mode, no external resistor should be used.
So RF is internal and the AGC replaces RS. Can Cx, Cy be implemented via the switchable internal capacitors (2,4,8,16pF controlled by bits SC[2,4,8,16]P)? 

I am dealing with a design intended to go to commodity volumes: my salary is worth less than a couple of capacitors! If I can remove them from the circuit, I've paid for myself.

0 Kudos
1 Reply

346 Views
miduo
NXP Employee
NXP Employee

Hi,

Yes, In High-Frequency, Low-Power Mode, the oscillator has the internal feedback resistor Rf. So an external resistor is no need.

0 Kudos