SLDS222C October 2019 – October 2023 TPS65313-Q1
PRODUCTION DATA
The integrated phase-locked loop (PLL) allows the device to synchronize the switched-mode regulator clocks to an external SYNC_IN input clock to help reduce EMI. When the TPS65313-Q1 device powers up, the device monitors the SYNC_IN pin for the presence of recurring clock edges. If the device detects activity on the SYNC_IN pin, the clock for the switched-mode regulators is derived from the external SYNC_IN clock. If the device does not detect any activity on the SYNC_IN pin, then the switched-mode regulators get a clock from the free-running VCO clock in the PLL.
When the system initially powers up without an external clock present at the SYNC_IN pin, the device enables the switched-mode regulators with the clock derived from the free-running VCO clock in the PLL. The device switches to an external clock source present at the SYNC_IN pin when the system powers up. The start of the regulator switching cycle is synchronized to the falling edge of the input clock at the SYNC_IN pin. If a loss-of-external clock event is detected, the clock source is switched to the free-running VCO clock to continue to regulate the output voltages.
An external clock should be connected to the SYNC_IN pin with a proper high-speed termination to avoid excessive ringing. The requirements on the external clock are as follows: