ZHCSJO3A May 2019 – October 2019 LMR34215-Q1
The following select variant(s) is/are a factory option made available for cases when constant frequency operation is more important than light load efficiency.
|ORDERABLE PART NUMBER||OUTPUT VOLTAGE||SPREAD SPECTRUM||FPWM||fSW|
|LMR34215FSC5RNXRQ1||5-V fixed||Yes||Yes||2.1 MHz|
|LMR34215FSC5RNXTQ1||5-V fixed||Yes||Yes||2.1 MHz|
In FPWM operation, the diode emulation feature is turned off. This means that the device remains in CCM under light loads. Under conditions where the device must reduce the on-time or off-time below the ensured minimum to maintain regulation, the frequency reduces to maintain the effective duty cycle required for regulation. This occurs for very high and very low input/output voltage ratios. When in FPWM mode, a limited reverse current is allowed through the inductor allowing power to pass from the regulator’s output to its input. Note that in FPWM mode, larger currents pass through the inductor, if lightly loaded, than in auto mode. Once loads are heavy enough to necessitate CCM operation, FPWM mode has no measurable effect on regulator operation.