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What accuracy of the capacitor used as the circuit constant added to the PLL is recommended?

Latest Updated:03/22/2017

Question:

(1) Can a +/-10% accurate capacitor be used as the circuit constant added to the PLL (VCNT pin)?
(2) If components with poor accuracy are used, what effects will they produce?

Answer:

(1) There is no problem using a +/-10% accurate capacitor as the circuit constant added to the PLL (VCNT pin).

(2) The external circuit for the VCNT pin is needed to maintain the stability of the analog voltage internally generated by the PLL and, in that sense, performs the role of a low-pass filter.
Dispersion of characteristics of the components used in this circuit may cause the chip's internal oscillating frequency to become unstable.
Furthermore, the chip's internal oscillating frequency is more significantly affected by external noise than by component accuracy. Therefore, by considering protection against external noise, please be sure to connect the external circuit as close to the pins as possible, in addition to paying attention to component accuracy.

Suitable Products
32170, 32174
32171
32172, 32173
32180
32182