Murata PE25203 User Manual page 10

The FREQ pin can be used to set the operating frequency of the PE25203. To save a resistor, the FREQ pin can also
be connected to GND to oscillate at a nominal 200 kHz. Note that this is the frequency of oscillation at the VX pin and
the charge pump frequency per phase will be switching at 50% of this value.
To adjust the frequency, a resistor of between 82.5 KΩ and 505 KΩ should be connected between the FREQ pin and
GND. The graph below shows the VX switching period versus the resistance value set at the FREQ pin.
Use the following equation to find the required VX switching period in µs.
Using a resistor value of 505 KΩ in the equation above,
Figure 7 shows the VX switching period vs. the resistance value set at the FREQ pin and Figure 8 shows the location
of FREQ resistor R2. PE25203 EVK uses a 499 KΩ resistor for R2.
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DOC-111189-2 (10/2023)
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Figure 7. VX Switching Period vs. Resistance Value on FREQ Pin
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