LM25085A

LM25085A www.ti.com SNVS601B – JANUARY 2009 – REVISED MARCH 2013 LM25085A 42V Constant On-Time PFET Buck Switching Controller with 0.9V Reference Check for Samples: LM25085A FEATURES 1 2 Wide 4.5V to 42V Input Voltage Range Adjustable Current Limit using RDS(ON) or a Current Sense Resistor Programmable Switching Frequency to 1MHz No Loop Compensation Required Ultra-Fast Transient Response Nearly Constant Operating Frequency with Line and Load Variations Adjustable Output Voltage from 0.9V Precision ±2% Feedback Reference Capable of 100% Duty Cycle Operation Internal Soft-Start Timer Integrated High Voltage Bias Regulator Thermal Shutdown PACKAGE HVSSOP-PowerPAD-8 VSSOP-8 WSON-8 (3 mm x 3 mm) DESCRIPTION The LM25085A is a functional variant of the LM25085 COT PFET Buck Switching Controller. The functional differences of the LM25085A are: The feedback reference voltage is 0.9V, the forced off-time after current limit detection is longer, and the soft-start time is shorter (1.8 ms). The LM25085A is a high efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, efficient buck regulator for a wide range of applications. This high voltage controller contains a PFET gate driver and a high voltage bias regulator which operates over a wide 4.5V to 42V input range. The constant on-time regulation principle requires no loop compensation, simplifies circuit implementation, and results in ultrafast load trans...