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LM5085

PGATE

ISEN

GND

VCC

ADJ

4.5V to 75V

Input

GND

SHUTDOWN

Q1

D1

L1

Cff

GND

VIN

RT

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LM5085, LM5085-Q1

SNVS565I – NOVEMBER 2008 – REVISED AUGUST 2015

LM5085/-Q1 75-V Constant On-Time PFET Buck Switching Controller

1 Features

3 Description

The LM5085 is a high efficiency PFET switching

1

•

LM5085-Q1 is an Automotive Grade Product that

regulator controller that can be used to quickly and

is AEC-Q100 Grade 1 Qualified (–40°C to 125°C

easily develop a small, efficient buck regulator for a

Operating Junction Temperature)

wide

range

of

applications.

This

high

voltage

•

Wide 4.5-V to 75-V Input Voltage Range

controller contains a PFET gate driver and a high

voltage bias regulator which operates over a wide

•

4.5-V to 75-V input range. The constant on-time

Current Sense Resistor

regulation principle requires no loop compensation,

•

Programmable Switching Frequency to 1MHz

simplifies

circuit

implementation,

and

results

in

•

No Loop Compensation Required

ultrafast load transient response. The operating

•

Ultra-Fast Transient Response

frequency remains nearly constant with line and load

variations due to the inverse relationship between the

•

Nearly Constant Operating Frequency with Line

input voltage and the on-time. The PFET architecture

and Load Variations

allows 100% duty cycle operation for a low dropout

•

Adjustable Output Voltage from 1.25 V

•

Precision ±2% Feedback Reference

sense resistor can be used to sense current for over-

current detection.

•

Capable of 100% Duty Cycle Operation

•

Internal Soft-start Timer

Device Information(1)

•

Integrated High Voltage Bias Regulator

PART NUMBER

PACKAGE

BODY SIZE (NOM)

•

Thermal Shutdown

VSSOP (8)

•

Package:

LM5085

HVSSOP (8)

3.00 mm x 3.00 mm

–

HVSSOP-8

WSON (8)

LM5085-Q1

HVSSOP (8)

3.00 mm x 3.00 mm

–

VSSOP-8

–

WSON-8

(1) For all available packages, see the orderable addendum at

the end of the datasheet.

2 Applications

•

Automotive Infotainment

•

Battery/Super Capacitor Chargers

•

LED Drivers

Typical Application, Basic Step Down Controller

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.