LM5145QRGYRQ1

The LM514575-V synchronous buckcontroller is designed to regulate from a high input voltage source or from an input rail subjectto high voltage transients, minimizing the need for external surge suppression components. Ahigh-side switch minimum on-time of 40 ns facilitates large step-down ratios, enabling the directstep-down conversion from a 48 V nominal input to low-voltage rails for reduced system complexity and solution cost. TheLM5145EVM-HD-20A continues tooperate during input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making itwell suited for high-performance industrial control, robotic, datacom, and RF power amplifierapplications.

Forced-PWM (FPWM) operation eliminates frequency variation to minimize EMI, while auser-selectable diode emulation feature lowers current consumption at light-load conditions.Cycle-by-cycle overcurrent protection is accomplished by measuring the voltage drop across thelow-side MOSFET or by using an optional current sense resistor. The adjustable switching frequencyas high as 1 MHz can be synchronized to an external clock source to eliminate beat frequencies innoise-sensitive applications.

The LM5145voltage-mode controller drives external high-side and low-side N-channel power switches with robust7.5-V gate drivers suitable for standard-threshold MOSFETs. Adaptively-timed gate drivers with2.3-A source and 3.5-A sink capability minimize body diode conduction during switching transitions,reducing switching losses and improving thermal performance when driving MOSFETs at high inputvoltage and high frequency. The LM5145EVM-HD-20A can be powered from the output of the switching regulator oranother available source, further improving efficiency.

A 180° out-of-phase clock output relative to the internal oscillator at SYNCOUT is idealfor cascaded or multi-channel power supplies to reduce input capacitor ripple current and EMIfilter size. Additional features of the LM5145EVM-HD-20A include a configurable soft-start, an open-drain Power Good monitorfor fault reporting and output monitoring, monotonic start-up into prebiased loads, integrated VCCbias supply regulator and bootstrap diode, external power supply tracking, precision enable inputwith hysteresis for adjustable line undervoltage lockout (UVLO), hiccup-mode overload protection,and thermal shutdown protection with automatic recovery.

The LM5145controller is offered in a 3.5-mm × 4.5-mm thermally-enhanced, 20-pin VQFN package with additionalspacing for high-voltage pins and wettable flanks for optical inspection of solder jointfillets.

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