The LM5085MME is a constant on-time non-synchronous PFET Buck Controller 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 4.5 to 75V input range. The constant on-time regulation principle requires no loop compensation, 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 over-current detection.
Adjustable current limit using RDS(ON) or a current sense resistor
No loop compensation required
Ultra-fast transient response
Nearly constant operating frequency with line and load variations
Precision ±2% Feedback reference
Internal soft-start timer
Integrated high voltage bias regulator
Thermal shutdown
Device has limited built-in ESD protection, leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
