LM5085-Q1

ACTIVE

Automotive Grade 4.5-75V Wide Vin, Constant On-Time Non-Synchronous PFET Buck Controller

A newer version of this product is available

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LM5141-Q1 ACTIVE Automotive wide-input 2.2-MHz low-IQ synchronous buck controller Optional spread spectrum for improved EMI.

Product details

Vin (min) (V) 4.5 Vin (max) (V) 75 Iout (max) (A) 10 Operating temperature range (°C) -40 to 125 Control mode Constant on-time (COT) Topology Buck Rating Automotive Vout (min) (V) 1.25 Vout (max) (V) 75 Features Adjustable current limit, Enable, Frequency synchronization Iq (typ) (µA) 1300 Duty cycle (max) (%) 100 Number of phases 1
Vin (min) (V) 4.5 Vin (max) (V) 75 Iout (max) (A) 10 Operating temperature range (°C) -40 to 125 Control mode Constant on-time (COT) Topology Buck Rating Automotive Vout (min) (V) 1.25 Vout (max) (V) 75 Features Adjustable current limit, Enable, Frequency synchronization Iq (typ) (µA) 1300 Duty cycle (max) (%) 100 Number of phases 1
HVSSOP (DGN) 8 14.7 mm² 3 x 4.9
  • LM5085-Q1 is an Automotive Grade Product that
    is AEC-Q100 Grade 1 Qualified (–40°C to 125°C
    Operating Junction Temperature)
  • Wide 4.5-V to 75-V 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 1.25 V
  • Precision ±2% Feedback Reference
  • Capable of 100% Duty Cycle Operation
  • Internal Soft-start Timer
  • Integrated High Voltage Bias Regulator
  • Thermal Shutdown
  • Package:
    • HVSSOP-8
    • VSSOP-8
    • WSON-8
  • LM5085-Q1 is an Automotive Grade Product that
    is AEC-Q100 Grade 1 Qualified (–40°C to 125°C
    Operating Junction Temperature)
  • Wide 4.5-V to 75-V 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 1.25 V
  • Precision ±2% Feedback Reference
  • Capable of 100% Duty Cycle Operation
  • Internal Soft-start Timer
  • Integrated High Voltage Bias Regulator
  • Thermal Shutdown
  • Package:
    • HVSSOP-8
    • VSSOP-8
    • WSON-8

The LM5085 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 4.5-V to 75-V 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.

The LM5085 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 4.5-V to 75-V 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.

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Technical documentation

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Type Title Date
* Data sheet LM5085/-Q1 75-V Constant On-Time PFET Buck Switching Controller datasheet (Rev. I) PDF | HTML 12 Aug 2015
EVM User's guide AN-1878 LM5085 Evaluation Board (Rev. B) 30 Apr 2013
Application note Constant Current Constant Voltage Buck Converter w/LM25085 (Rev. A) 23 Apr 2013
Application note Designing Non-Invert Buck-Boost (Zeta) Cnvrts w/a Buck P-FET Cntrl 22 Apr 2011

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM5085EVAL — LM5085 - 75V Wide Vin Constant On-Time PFET Buck Switching Controller Evaluation Module

The LM5085 evaluation board provides the design engineer with a fully functional buck regulator, employing the LM5085 PFET switching controller which uses the constant on-time (COT) operating principle. The evaluation board provides a 5V output over an input range of 5.5V to 55V. The circuit (...)

User guide: PDF
Not available on TI.com
Simulation model

LM5085 PSpice Transient Model (Rev. A)

SNVM213A.ZIP (135 KB) - PSpice Model
Simulation model

LM5085 PSpice Unencrypted Transient Model (Rev. B)

SNVM213B.ZIP (147 KB) - PSpice Model
Simulation model

LM5085 TINA-TI Load Transient Reference Design (Rev. A)

SNVM496A.TSC (135 KB) - TINA-TI Reference Design
Simulation model

LM5085 TINA-TI Startup Reference Design (Rev. A)

SNVM497A.TSC (136 KB) - TINA-TI Reference Design
Simulation model

LM5085 TINA-TI Transient Spice Model (Rev. A)

SNVM498A.ZIP (20 KB) - TINA-TI Spice Model
Simulation model

LM5085 Unencrypted PSpice Transient Model

SNVM955.ZIP (3 KB) - PSpice Model
Calculation tool

LM25085-5085QUICK-CALC — LM(2)5085 Quick Start Calculator

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