ZHCS520E May 1996 – May 2019 LM2586
PRODUCTION DATA.
The switching frequency of the LM2586 can be adjusted with the use of an external resistor. This feature allows the user to optimize the size of the magnetics and the output capacitor(s) by tailoring the operating frequency. A resistor connected from pin 1 (the Freq. Adj. pin) to ground will set the switching frequency from 100 kHz to 200 kHz (maximum). As shown in Figure 23, the pin can be used to adjust the frequency while still providing the shutdown function. A curve in Typical Characteristics the resistor value to the corresponding switching frequency. Table 1 shows resistor values corresponding to commonly used frequencies.
However, changing the LM2586 operating frequency from its nominal value of 100 kHz changes the magnetics selection and compensation component values.
RSET(kΩ) | Frequency (kHz) |
---|---|
Open | 100 |
200 | 125 |
47 | 150 |
33 | 175 |
22 | 200 |