Monolithic Power Systems (MPS) MP4321 Configurable-Frequency Step-Down Converters are configurable-frequency (350kHz to 2.5MHz), synchronous devices with integrated internal high-side and low-side power MOSFETs (HS-FET and LS-FET, respectively). The MP4321 achieves up to 1A of highly efficient output current (IOUT) with peak current control mode. The wide 3.3V to 36V input voltage (VIN) range and 42V load dump tolerance of the converters allow a variety of step-down applications in automotive input environments. A 1μA shutdown current (ISD) enables the devices to be used in battery-powered applications.
The MPS MP4321 configurable-frequency step-down converters provide high power conversion efficiency across the entire load range via scaling down the switching frequency (fSW) under light-load conditions to decrease switching and gate driver losses. The open drain power good (PG) signal indicates whether the output is within 94.5% to 105.5% of its nominal voltage, while the frequency foldback prevents inductor current (IL) runaway during start-up.
Thermal shutdown allows reliable, fault-tolerant operation meanwhile, a high-duty cycle and low-dropout (LDO) mode implement automotive cold crank conditions.
The MP4321 is engineered in a QFN-12 (2mm x 3mm) package with wettable flanks.









