500-kHz wide VIN nonsynchronous boost, flyback, & SEPIC controller


Product details


Vin (Min) (V) 1.5 Vin (Max) (V) 40 Vout (Min) (V) 1.5 Vout (Max) (V) 300 Regulated outputs (#) 1 Switching frequency (Min) (kHz) 100 Switching frequency (Max) (kHz) 500 Iq (Typ) (mA) 0.49 Features Adjustable Current Limit, Enable, Light Load Efficiency, Power Good, UVLO Adjustable Duty cycle (Max) (%) 93 Rating Automotive Operating temperature range (C) -40 to 150 open-in-new Find other Boost controllers (external switch)

Package | Pins | Size

HTSSOP (PWP) 14 32 mm² 5 x 6.4 open-in-new Find other Boost controllers (external switch)


  • AEC-Q100 qualified for automotive applications
    • Temperature grade 1: –40°C to +125°C TA
    • Maximum operating temperature 150°C TJ
  • Functional Safety-Capable
  • Suited for wide input operating range car battery applications
    • 3.5-V to 40-V operating range (45-V abs max)
    • 2.97-V to 16-V when BIAS = VCC
    • Minimum boost supply voltage 1.5 V when BIAS ≥ 3.5 V
    • Input transient protection up to 45 V
    • Minimized battery drain
      • Low shutdown current ( IQ ≤ 2.6 µA )
      • Low operating current ( IQ ≤ 490 µA )
  • Small solution size and low cost
    • Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
    • Minimized undershoot during cranking (start-stop application)
  • Higher efficiency with low-power dissipation
    • 100-mV ±7% accurate current limit threshold
    • Strong 1.0-A peak standard MOSFET driver
    • Supports external VCC supply
  • Avoid AM band interference and crosstalk
    • Optional clock synchronization
    • Dynamically programmable switching frequency from 100 kHz to 500 kHz
  • Integrated protection features
    • Constant peak current limiting over input voltage
    • Hiccup mode overload protection
    • Programmable line UVLO
    • OVP protection
    • Thermal shutdown
  • Accurate ±1% accuracy feedback reference
  • Programmable extra slope compensation
  • Adjustable soft start
  • PGOOD indicator
  • 14-Pin HTSSOP package (5.0 mm × 4.4 mm)
  • Create a custom design using the LM34966-Q1 with the WEBENCH power designer

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The LM34966-Q1 is a wide input range, non-synchronous boost controller that uses peak current mode control. The device can be used in boost, SEPIC, and flyback topologies. The device can start up from a 1-cell battery with a minimum of 2.97 V if the BIAS pin is connected to the VCC pin. It can operate with the input supply voltage as low as 1.5 V if the BIAS pin is greater than 3.5 V. The internal VCC regulator also supports BIAS pin operation up to 40 V (45-V absolute maximum) for automotive load dump. The switching frequency is dynamically programmable with an external resistor from 100 kHz to 500 kHz.

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Technical documentation

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Type Title Date
* Data sheet LM34966-Q1 500kHz Wide VIN Non-synchronous Boost/SEPIC/Flyback Controller datasheet Sep. 23, 2020
Functional safety information LM34966-Q1, LM5156x-Q1 Functional Safety, FIT Rate, Failure Mode Distribution (Rev. C) Apr. 28, 2021
User guide LM34966EVM-FLY Flyback Evaluation Module Sep. 28, 2020
Certificate LM34966EVM-FLY EU Declaration of Conformity (DoC) Sep. 10, 2020
Technical article How to add overvoltage protection to a synchronous boost controller Sep. 17, 2018

Design & development

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Hardware development

document-generic User guide
The LM34966EVM-FLY evaluation module showcases the features and performance of the LM34966-Q1 as wide input non-synchronous flyback controller. The standard configuration is designed to provide a regulated output of 5V at 4A from an input of 18V to 36V, switching at 250 kHz. This evaluation (...)
  • Input voltage range: 18V to 36V
  • Isolate output voltage 5V at 4A
  • Switching frequency 250kHz
  • Hiccup mode short circuit protection

Design tools & simulation

SNVMC41A.ZIP (222 KB) - PSpice Model
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — 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 (...)
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)

CAD/CAE symbols

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HTSSOP (PWP) 14 View options

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