Description

The 42-V synchronous buck controller LM25145RGYR is designed to regulate from a high input voltage source or an input rail prone to high voltage transients, reducing the requirement for extra surge suppression components. Large step-down ratios are enabled by a high-side switch minimum on-time of 40 ns, allowing direct step-down conversion from a 24 V nominal input to low-voltage rails for decreased system complexity and solution cost. The LM25145RGYR can operate at nearly 100% duty cycle during input voltage dips as low as 6 V, making it ideal for high-performance industrial control, robotics, datacom, and RF power amplifier applications.

A user-selectable diode emulation function minimizes current consumption at light-load settings, while forced-PWM (FPWM) operation eliminates frequency variation to reduce EMI. Overcurrent protection is achieved by detecting the voltage drop across the low-side MOSFET or by employing an optional current sense resistor on a cycle-by-cycle basis. To reduce beat frequencies in noise-sensitive applications, the configurable switching frequency of up to 1 MHz can be synchronized to an external clock source.

Features

? Precision Enable Input and Open-Drain Power Good Indicator for Sequencing and Control

? Inherent Protection Features for Robust Design

– Hiccup Mode Overcurrent Protection

– Input UVLO With Hysteresis

– VCC and Gate Drive UVLO Protection

– Thermal Shutdown Protection With Hysteresis

? VQFN-20 Package With Wettable Flanks

? Create a Custom Design Using the LM25145 With WEBENCH? Power Designer

? 40-ns Minimum On-Time for High VIN / VOUT Ratio

? 140-ns Minimum Off-Time for Low Dropout

? 0.8-V Reference With ±1% Feedback Accuracy

? 7.5-V Gate Drivers for Standard VTH MOSFETs

– 14-ns Adaptive Dead-Time Control

– 2.3-A Source and 3.5-A Sink Capability

– Low-Side Soft-Start for Prebiased Start-Up

? Adjustable Soft-Start or Optional Voltage Tracking

? Fast Line and Load Transient Response

– Voltage-Mode Control With Line Feedforward

– High Gain-Bandwidth Error Amplifier

? Versatile Synchronous Buck DC-DC Controller

– Wide Input Voltage Range of 6 V to 42 V

– Adjustable Output Voltage From 0.8 V to 40 V

? Meets EN55022 / CISPR 22 EMI Standards

? Lossless RDS(on) or Shunt Current Sensing

? Switching Frequency From 100 kHz to 1 MHz

– SYNC In and SYNC Out Capability

Applications

? Telecom Infrastructure

? Factory Automation

? Test and Measurement

? Industrial Motor Drives

? RF Power Amplifier Applications