TPS6281x-Q1 has two operating modes: Forced PWM mode (discussed in this section) and PWM/PFM (discussed in Section 9.4.2).
With the MODE/SYNC pin set to high, the TPS6281x-Q1 operates with pulse width modulation in continuous conduction mode (CCM). The switching frequency is either defined by a resistor from the COMP pin to GND or by an external clock signal applied to the MODE/SYNC pin. With an external clock is applied to MODE/SYNC, the TPS6281x-Q1 follows the frequency applied to the pin. To maintain regulation, the frequency needs to be in a range the TPS6281x-Q1 can operate at, taking the minimum on-time into account.