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LM25085

ACTIVE

4.5-42V Wide Vin, Constant On-Time Non-Synchronous PFET Buck Controller

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LM25148 ACTIVE 42-V synchronous buck DC/DC controller with ultra-low IQ Improved EMI performance with QFN package and dual random spread spectrum.

Product details

Vin (min) (V) 4.5 Vin (max) (V) 42 Vout (min) (V) 1.25 Vout (max) (V) 42 Iout (max) (A) 10 Iq (typ) (mA) 1.25 Switching frequency (min) (kHz) 50 Switching frequency (max) (kHz) 1000 Features Adjustable current limit, Enable, Frequency synchronization Operating temperature range (°C) -40 to 125 Regulated outputs (#) 1 Number of phases 1 Rating Catalog Control mode Constant on-time (COT) Type Controller
Vin (min) (V) 4.5 Vin (max) (V) 42 Vout (min) (V) 1.25 Vout (max) (V) 42 Iout (max) (A) 10 Iq (typ) (mA) 1.25 Switching frequency (min) (kHz) 50 Switching frequency (max) (kHz) 1000 Features Adjustable current limit, Enable, Frequency synchronization Operating temperature range (°C) -40 to 125 Regulated outputs (#) 1 Number of phases 1 Rating Catalog Control mode Constant on-time (COT) Type Controller
HVSSOP (DGN) 8 14.7 mm² 3 x 4.9 VSSOP (DGK) 8 14.7 mm² 3 x 4.9 WSON (NGQ) 8 9 mm² 3 x 3
  • LM25085-Q1 is an Automotive Grade product that is
    AEC-Q100 Grade 1 Qualified (–40°C to 125°C
    Operating Junction Temperature)
  • 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 1.25V
  • Precision ±2% Feedback Reference
  • Capable of 100% Duty Cycle Operation
  • Internal Soft-Start Timer
  • Integrated High Voltage Bias Regulator
  • Thermal Shutdown
  • LM25085-Q1 is an Automotive Grade product that is
    AEC-Q100 Grade 1 Qualified (–40°C to 125°C
    Operating Junction Temperature)
  • 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 1.25V
  • Precision ±2% Feedback Reference
  • Capable of 100% Duty Cycle Operation
  • Internal Soft-Start Timer
  • Integrated High Voltage Bias Regulator
  • Thermal Shutdown

The LM25085 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 ultra-fast 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 LM25085 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 ultra-fast 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 LM25085 / -Q1 42V Constant On-Time PFET Buck Switching Controller datasheet (Rev. J) PDF | HTML 03 Nov 2014
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Application note Transient Response versus Ripple – An Analysis of Ripple Injection Techniques 28 Apr 2014
Application note Automated Frequency Response Analyzer 09 Oct 2013
EVM User's guide AN-1905 LM25085 Evaluation Board (Rev. B) 26 Apr 2013
Application note Constant Current Constant Voltage Buck Converter w/LM25085 (Rev. A) 23 Apr 2013

Design & development

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Evaluation board

LM25085MYEVAL — Evaluation Board for LM25085 - 42V Wide Vin Constant On-Time PFET Buck Switching Controller

The LM25085 evaluation board provides the design engineer with a fully functional buck regulator, employing the LM25085 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 42V. The circuit (...)

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

LM25085 PSpice Transient Model

SNVM302.ZIP (99 KB) - PSpice Model
Simulation model

LM25085 Unencrypted PSpice Transient Model

SNVMAF8.ZIP (3 KB) - PSpice Model
Calculation tool

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

Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
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HVSSOP (DGN) 8 View options
VSSOP (DGK) 8 View options
WSON (NGQ) 8 View options

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