NX9548 4.5 V to 24 V, 8 A Adaptive Constant On Time (COT) Synchronous Buck Regulator Description Features Adaptive COT Control The NX9548 is a synchronous buck switching regulator with 21 m internal N-channel MOSFETs, primarily Adjustable, Constant Switching Frequency intended for portable (mobile) applications. The up to 1 MHz NX9548 operates from 4.5 V to 24 V, and the output Extremely Low-RDSON N-MOSFETs voltage range is from 0.75 V to 5 V, with output currents Bus Voltage 4.5 V to 24 V as high as 8 A. It can be selected to operate in Selectable Diode Emulation Mode (PSM synchronous mode, or non-synchronous (diode Mode) emulation or PSM) mode at light loads, to improve Current Limit, UVLO, OVP efficiency. Gate Resistor Provision for EMI Reduction Adaptive constant on time (COT) control provides -40C to +85C Ambient Temperature extremely fast transient response to line and load steps, -40C to +150C Junction Temperature while at the same time providing near-constant switching frequency over a wide input voltage range. RoHS Compliant The frequency is also externally adjustable. 55 mm Very Thin Profile QFN (VQFN) Package The NX9548 features overcurrent protection (OCP), feedback under-voltage lockout (FB UVLO), and overvoltage protection (OVP). It also includes an Applications integrated bootstrap Schottky diode, and provides low- Ultramobile/Notebook PCs voltage (5 V) gate-drive capability. In addition it Tablets/Slates provides a Power Good indicator and has adaptive dead Hand-held Portable Instruments time. ADSL Modem July 2015 Rev. 1.2 www.microsemi.com 1 2015 Microsemi Corporation 4.5 V to 24 V, 8 A Adaptive Constant On Time (COT) Synchronous Buck Regulator Typical Application Diagram Figure 1 Typical Application Diagram for Low-Input Voltages Figure 2 Typical Application Diagram for Wide Input Range 2