SLVS500D DECEMBER 2003 – June 2019 TPS54110
PRODUCTION DATA.
Refer to the PDF data sheet for device specific package drawings
The oscillator frequency can be set to internally fixed values of 350 kHz or 550 kHz using the SYNC pin as a static digital input. If a different frequency of operation is required for the application, the oscillator frequency can be externally adjusted from 280 kHz to 700 kHz by connecting a resistor from the RT pin to ground and floating the SYNC pin. The switching frequency is approximated by the following equation, where R is the resistance from RT to AGND:
External synchronization of the PWM ramp is possible over the frequency range of 330 kHz to 700 kHz by driving a synchronization signal into SYNC and connecting a resistor from RT to AGND. Choose an RT resistor that sets the free-running frequency to 80% of the synchronization signal. Table 1 summarizes the frequency selection configurations.
SWITCHING FREQUENCY | SYNC PIN | RT PIN |
---|---|---|
350 kHz, internally set | Float or AGND | Float |
550 kHz, internally set | ≥ 2.5 V | Float |
Externally set 280 kHz to 700 kHz | Float | R = 68 k to 180 k |
Externally synchronized frequency | Synchronization signal | R = RT value for 80% of external synchronization frequency |