LM3485

ACTIVE

4.5-35V, Hysteretic 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) 35 Iout (max) (A) 4 Operating temperature range (°C) -40 to 125 Control mode Hysteretic Topology Buck Controller Rating Catalog Vout (min) (V) 1.242 Vout (max) (V) 35 Features Enable Iq (typ) (µA) 250 Duty cycle (max) (%) 100 Number of phases 1
Vin (min) (V) 4.5 Vin (max) (V) 35 Iout (max) (A) 4 Operating temperature range (°C) -40 to 125 Control mode Hysteretic Topology Buck Controller Rating Catalog Vout (min) (V) 1.242 Vout (max) (V) 35 Features Enable Iq (typ) (µA) 250 Duty cycle (max) (%) 100 Number of phases 1
VSSOP (DGK) 8 14.7 mm² 3 x 4.9
  • Easy-to-Use Control Methodology
  • No Control-Loop Compensation Required
  • 4.5-V to 35-V Wide Input Range
  • 1.242-V to VIN Adjustable Output Range
  • High Efficiency 93%
  • ±1.3% (±2% Over Temp) Internal Reference
  • 100% Duty Cycle
  • Maximum Operating Frequency > 1 MHz
  • Current Limit Protection
  • Easy-to-Use Control Methodology
  • No Control-Loop Compensation Required
  • 4.5-V to 35-V Wide Input Range
  • 1.242-V to VIN Adjustable Output Range
  • High Efficiency 93%
  • ±1.3% (±2% Over Temp) Internal Reference
  • 100% Duty Cycle
  • Maximum Operating Frequency > 1 MHz
  • Current Limit Protection

The LM3485 is a high-efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, low-cost, switching buck regulator for a wide range of applications. The hysteretic control architecture provides for simple design without any control-loop stability concerns using a wide variety of external components. The PFET architecture also allows for low component count as well as ultralow dropout, 100% duty cycle operation. Another benefit is high efficiency operation at light loads without an increase in output ripple.

Current limit protection is provided by measuring the voltage across the RDS(ON) of the PFET, thus eliminating the need for a sense resistor. The cycle-by-cycle current limit can be adjusted with a single resistor, ensuring safe operation over a range of output currents.

The LM3485 is a high-efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, low-cost, switching buck regulator for a wide range of applications. The hysteretic control architecture provides for simple design without any control-loop stability concerns using a wide variety of external components. The PFET architecture also allows for low component count as well as ultralow dropout, 100% duty cycle operation. Another benefit is high efficiency operation at light loads without an increase in output ripple.

Current limit protection is provided by measuring the voltage across the RDS(ON) of the PFET, thus eliminating the need for a sense resistor. The cycle-by-cycle current limit can be adjusted with a single resistor, ensuring safe operation over a range of output currents.

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Technical documentation

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Type Title Date
* Data sheet LM3485 Hysteretic PFET Buck Controller datasheet (Rev. H) PDF | HTML 28 Dec 2015
Analog Design Journal Control-Mode Quick Reference Guide (Rev. B) PDF | HTML 29 Aug 2023
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Analog Design Journal Reduce buck-converter EMI and voltage stress by minimizing inductive parasitics 21 Jul 2016
EVM User's guide AN-1227 LM3485 Evaluation Board (Rev. B) 25 Apr 2013
EVM User's guide AN-1392 LM3485 LED Demo Board (Rev. B) 25 Apr 2013

Design & development

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

Evaluation board

LM3485EVAL — Hysteretic PFET Buck Controller Evaluation Module

Hysteretic PFET Buck Controller

User guide: PDF
Not available on TI.com
Evaluation board

LM3485LED-EVAL — Hysteretic PFET Buck Controller

The LM3485 LED driver board is a buck regulator derived controlled current source designed to drive high power, high brightness LEDs (HBLEDs) such as the Luxeon™ Emitter at dissipations of 1W to 5W. The board can accept an input voltage ranging from 5V to 30V and can control the output current (...)

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

LM3485 PSpice Transient Model

SNVM296.ZIP (44 KB) - PSpice Model
Simulation model

LM3485 Unencrypted PSpice Transient Model

SNVM716.ZIP (2 KB) - PSpice Model
Package Pins CAD symbols, footprints & 3D models
VSSOP (DGK) 8 Ultra Librarian

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