It is often desirable to synchronize the operation of multiple regulators in a single system, resulting in a well-defined system level performance. The select variants in the LMR436x0-Q1 with the MODE/SYNC pin allow the power designer to synchronize the device to a common external clock. The LMR436x0-Q1 implements an in-phase locking scheme, where the rising edge of the clock signal, provided to the MODE/SYNC pin of the LMR436x0-Q1, corresponds to the turning on of the high-side device. The external clock synchronization is implemented using a phase locked loop (PLL), eliminating any large glitches. The external clock fed into the LMR436x0-Q1 replaces the internal free-running clock, but does not affect any frequency foldback operation. Output voltage continues to be well-regulated. The device remains in FPWM mode and operates in CCM for light loads when synchronization input is provided.
The MODE/SYNC input pin in the LMR436x0-Q1 can operate in one of three selectable modes: