LM25085A Datasheet | Texas Instruments

.ti. SNVS601B - JANUARY 2009 - REVISED MARCH 2013 LM25085A 42V Constant On-Time PFET Buck Switching Controller with 0.9V Reference Check for Samples: LM25085A Features - 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 pensation 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-Power PAD-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 pensation, simplifies circuit implementation, and results in ultrafast load transient response. The operating frequency remains nearly constant with line and load variations due to the inverse relationship between the input voltage and the on-time. The PFET architecture allows 100% duty cycle operation for a low dropout voltage. Either the RDS(ON) of the PFET or an external sense resistor can be used to sense current for overcurrent detection. Typical Application, Basic Step Down Controller 4.5V to 42V...