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AC/DC & DC/DC converters (integrated FET)

LM34925

ACTIVE

7.5-100V Wide Vin, 100mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters

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Data sheet

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LM5168 ACTIVE 6-V to 120-V wide VIN, 300-mA DC-DC converter with Fly-Buck™ capability 120-V rating and lower IQ.

LM34925

ACTIVE
Data sheet Order now

Product details

Rating Catalog Operating temperature range (°C) -40 to 125 Topology Buck, Flybuck Type Converter Iout (max) (A) 0.1 Vin (min) (V) 9 Vin (max) (V) 100 Switching frequency (min) (kHz) 150 Switching frequency (max) (kHz) 1000 Features Enable, Synchronous Rectification, UVLO adjustable Control mode Constant on-time (COT) Vout (min) (V) 1.25 Vout (max) (V) 90 Duty cycle (max) (%) 90 Switch current limit (typ) (A) 0.3
Rating Catalog Operating temperature range (°C) -40 to 125 Topology Buck, Flybuck Type Converter Iout (max) (A) 0.1 Vin (min) (V) 9 Vin (max) (V) 100 Switching frequency (min) (kHz) 150 Switching frequency (max) (kHz) 1000 Features Enable, Synchronous Rectification, UVLO adjustable Control mode Constant on-time (COT) Vout (min) (V) 1.25 Vout (max) (V) 90 Duty cycle (max) (%) 90 Switch current limit (typ) (A) 0.3
HSOIC (DDA) 8 29.4 mm² 4.9 x 6 WSON (NGU) 8 16 mm² 4 x 4
  • Wide 7.5-V to 100-V Input Range
  • Integrated 100-mA High-Side,
    and Low-Side Switches
  • No Schottky Required
  • Constant On-Time Control
  • No Loop Compensation Required
  • Ultra-Fast Transient Response
  • Nearly Constant Operating Frequency
  • Intelligent Peak Current Limit
  • Adjustable Output Voltage From 1.225 V
  • Precision 2% Feedback Reference
  • Frequency Adjustable to 1 MHz
  • Adjustable Undervoltage Lockout (UVLO)
  • Remote Shutdown
  • Thermal Shutdown
  • Packages:
    • 8-Pin WSON
    • 8-Pin SO PowerPAD™
  • Wide 7.5-V to 100-V Input Range
  • Integrated 100-mA High-Side,
    and Low-Side Switches
  • No Schottky Required
  • Constant On-Time Control
  • No Loop Compensation Required
  • Ultra-Fast Transient Response
  • Nearly Constant Operating Frequency
  • Intelligent Peak Current Limit
  • Adjustable Output Voltage From 1.225 V
  • Precision 2% Feedback Reference
  • Frequency Adjustable to 1 MHz
  • Adjustable Undervoltage Lockout (UVLO)
  • Remote Shutdown
  • Thermal Shutdown
  • Packages:
    • 8-Pin WSON
    • 8-Pin SO PowerPAD™

The LM34925 regulator features all of the functions needed to implement a low cost, efficient, isolated bias regulator. This high voltage regulator contains two 100-V N-Channel MOSFET switches: a high-side buck switch and a low-side synchronous switch. The constant-on-time (COT) control scheme employed in the LM34925 device requires no loop compensation and provides excellent transient response. The regulator operates with an on-time that is inversely proportional to the input voltage. This feature allows the operating frequency to remain relatively constant. An intelligent peak current limit is implemented with integrated sense circuit. Other features include a programmable input under voltage comparator to inhibit operation during low-voltage conditions. Protection features include thermal shutdown and VCC undervoltage lockout (UVLO). The LM34925 device is offered in 8-pin WSON and
8-pin SO PowerPAD plastic packages.

The LM34925 regulator features all of the functions needed to implement a low cost, efficient, isolated bias regulator. This high voltage regulator contains two 100-V N-Channel MOSFET switches: a high-side buck switch and a low-side synchronous switch. The constant-on-time (COT) control scheme employed in the LM34925 device requires no loop compensation and provides excellent transient response. The regulator operates with an on-time that is inversely proportional to the input voltage. This feature allows the operating frequency to remain relatively constant. An intelligent peak current limit is implemented with integrated sense circuit. Other features include a programmable input under voltage comparator to inhibit operation during low-voltage conditions. Protection features include thermal shutdown and VCC undervoltage lockout (UVLO). The LM34925 device is offered in 8-pin WSON and
8-pin SO PowerPAD plastic packages.
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Technical documentation

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Type Title Date
* Data sheet LM34925 Integrated Secondary-Side Bias Regulator for Isolated DC-DC Converters datasheet (Rev. G) PDF | HTML 20 Nov 2017
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Analog Design Journal Fly-Buck(TM) converter provides EMC and isolation in PLC applications 29 Jan 2015
Application note AN-2292 Designing an Isolated Buck (Fly-Buck) Converter (Rev. C) 17 Dec 2014
User guide AN-2204 LM5017 Isolated Supply Evaluation Board (Rev. B) 13 Aug 2013
User guide LM34925 Isolated Evaluation Board (Rev. A) 23 Apr 2013

Design & development

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

Evaluation board

LM34925EVAL — LM34925 Isolated Bias Supply Evaluation Module

The LM34925EVAL evaluation board facilitates evaluation of the LM34925 100V, 100mA Constant On-Time Synchronous Buck Regulator. An isolated bias supply is implemented in this evaluation board with the LM34925 the Constant On-Time regulator. The LM34925 regulator integrates both the high and low (...)
User guide: PDF
Not available on TI.com
Simulation model

LM34925 PSpice Transient Model (Rev. A)

SNVM163A.ZIP (34 KB) - PSpice Model
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Simulation model

LM34925 TINA-TI Reference Design

SNVM375.TSC (192 KB) - TINA-TI Reference Design
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Simulation model

LM34925 TINA-TI Transient Spice Model

SNVM376.ZIP (10 KB) - TINA-TI Spice Model
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Simulation model

LM34925 Unencrypted PSpice Transient Model

SNVM980.ZIP (2 KB) - PSpice Model
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Calculation tool

FLYBUCK-FLYBACK-DESIGN-CALC — Flybuck / Flyback Calculator

This tool helps a power supply engineer to select the right isolated DC-DC topology based on the specifications. Depending on the topology chosen, the calculator also recommends the right IC for the design.

Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
LM3017 — High Efficiency Low-Side Controller with True Shutdown LM3478 — 2.97~40V Wide Input Range Boost/SEPIC/Flyback DC-DC Controller LM3478Q-Q1 — 40-V wide VIN low-side N-channel controller for switching regulators with 10-µA shutdown current LM3481 — 2.97V to 48V High-Efficiency Controller for Boost, SEPIC and Flyback LM3481-Q1 — 2.97-V to 48-V high-efficiency controller for boost, SEPIC and flyback, AEC-Q100 qualified LM3488 — 2.97V to 40V Wide Vin Low-Side N-Channel Controller for Switching Regulators LM3488Q-Q1 — 40-V wide VIN low-side N-channel controller for switching regulators with 5-µA shutdown current LM3524D — 40V, 0.2A 350KHz PWM controller LM3578A — 2-V to 40-VIN switching regulators in buck, boost, terminal, depending upon the application LM5020 — 13-100V Wide Vin, Current Mode PWM Boost, Flyback, Sepic Controller LM5022 — 6-60V Wide Vin, current mode boost, SEPIC and Flyback controller TL1451 — Dual Pulse-Width-Modulation Control Circuit TL1451A — 3.6V to 50V dual channel controller with Wide input voltage range TL1451A-EP — Enhanced Product Dual Pulse-Width-Modulation Control Circuits TL1451A-Q1 — 3.6-V to 50-V dual-channel PWM controller, AEC-Q100 qualified TL5001 — PWM Controller with wide input range, with ±5% tolerance on reference, operation –20°C to 85°C TL5001A — PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°C TL5001A-Q1 — PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°C TL5001M — PWM Controller with wide input range, with ±5% tolerance on reference, operation –55°C to 125°C TPS40210-Q1 — 4.5-V to 52-V wide input range current mode boost controller with 700-mV reference voltage TPS40211-Q1 — 4.5-V to 52-V wide input range current mode boost controller with 260-mV reference voltage TPS43000 — Multi-Topology (buck, boost, sepic) High Frequency DC/DC Controller TPS55010 — 2.95V To 6V Input, 2W, Isolated DC/DC Converter with Integrated FETS UC2572 — Negative output Flyback pulse width modulator
AC/DC & DC/DC converters (integrated FET)
LM25017 — 7.5-48V Wide Vin, 650mA Constant On-Time Synchronous Buck Regulator LM25018 — 7.5-48V Wide Vin, 300mA Constant On-Time Synchronous Buck Regulator LM25019 — 7.5-48V Wide Vin, 100mA Constant On-Time Synchronous Buck Regulator LM2577 — 3.5-V to 40-V, 3-A low component count step-up regulator LM2585 — 4-V to 40-V, 3-A step-up wide VIN flyback regulator LM2586 — 4-V to 40-V, 3-A step-up wide VIN flyback regulator with frequency synchronization LM2587 — 4V to 40V, 5A Step-Up Wide Vin Flyback Regulator LM2588 — 4-V to 40-V, 5-A step-up wide VIN flyback regulator with frequency synchronization LM2621 — 1.2V to 14V input voltage, 1A load current, step-up DC-DC LM2623 — 0.8V to 14V input voltage, 2A load current, step-up DC-DC LM2623-Q1 — 0.8-V to 14-V input voltage, 2-A load current, step-up DC/DC, AEC-Q100 qualified LM2735 — 520kHz/1.6MHz space efficient boost and SEPIC DC-DC regulator LM2735-Q1 — 520-kHz, 1.6-MHz space efficient boost and SEPIC DC/DC regulator, AEC-Q100 qualified LM34925 — 7.5-100V Wide Vin, 100mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM34926 — 7.5-100V Wide Vin, 300mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM34927 — 7.5-100V Wide Vin, 600mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM5000 — 3.1-40V Wide Vin, 2A Current Mode Non-Synchronous Boost Regulator LM5001 — 3.1-75V Wide Vin, 1A Current Mode Non-Synchronous Switch Mode Regulator LM5001-Q1 — 3.1-V to 75-V wide VIN, 1-A current mode non-synchronous switch mode regulator LM5002 — 3.1-75V Wide Vin, 0.5A Current Mode Boost, Flyback, Sepic Converter LM5015 — 4.25-75V, Monolithic Two-Switch Forward DC-DC Regulator LM5017 — 7.5-100V Wide Vin, 600mA Constant On-Time Synchronous Buck Regulator LM5018 — 7.5-100V Wide Vin, 300mA Constant On-Time Synchronous Buck Regulator LM5019 — 7.5-100V Wide Vin, 100mA Constant On-Time Synchronous Buck Regulator LM5160 — LM5160 wide input 65V, 2A synchronous buck/Fly-Buck™ converter LM5160-Q1 — Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ Converter LM5160A — LM5160A Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ Converter LM5161 — Wide Input 4.5-V to 100-V, 1-A Synchronous Buck / Fly-Buck Converter LM78S40 — 1.5A Adjustable Step Up, Step Down or Inverting Regulator TPS55340 — 5-A, 40-V, wide VIN boost, flyback, & SEPIC converter TPS55340-EP — Enhanced integrated, 5-A, 40-V wide input range boost/SEPIC/flyback DC/DC regulator TPS55340-Q1 — Integrated, 5-A 40-V wide input range boost/SEPIC/flyback DC/DC regulator, AEC-Q100 qualified TPS61175 — 3-A ,40V High Voltage Boost Converter with Soft-start and Programmable Switching Frequency TPS61175-Q1 — 3-A, 40-V high voltage boost converter with soft-start and programmable switching frequency
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Package Pins CAD symbols, footprints & 3D models
HSOIC (DDA) 8 Ultra Librarian
WSON (NGU) 8 Ultra Librarian
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Information included:
  • Fab location
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