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LM34938-Q1

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Automotive, 36V VIN four-switch buck-boost controller with I2C and 2.2MHz fsw for wireless charging

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Data sheet

LM34938-Q1

PREVIEW
Data sheet Order now

Product details

Rating Automotive Topology Buck-Boost Vin (max) (V) 36 Vin (min) (V) 3.5 Vout (max) (V) 45 Vout (min) (V) 1 Features Adjustable current limit, Dynamic voltage scaling, Enable, Forced PWM, Frequency synchronization, I2C, Light load efficiency, Load Disconnect, Output discharge, Power good, Synchronous rectification, Tracking, UVLO adjustable EMI features Frequency Dithering, Spread Spectrum Duty cycle (max) (%) 100 Iq (typ) (A) 0.000065 TI functional safety category Functional Safety-Capable Operating temperature range (°C) to
Rating Automotive Topology Buck-Boost Vin (max) (V) 36 Vin (min) (V) 3.5 Vout (max) (V) 45 Vout (min) (V) 1 Features Adjustable current limit, Dynamic voltage scaling, Enable, Forced PWM, Frequency synchronization, I2C, Light load efficiency, Load Disconnect, Output discharge, Power good, Synchronous rectification, Tracking, UVLO adjustable EMI features Frequency Dithering, Spread Spectrum Duty cycle (max) (%) 100 Iq (typ) (A) 0.000065 TI functional safety category Functional Safety-Capable Operating temperature range (°C) to
VQFN (RHA) 40 36 mm² 6 x 6
  • Input range from 3.5V to 36V
  • Dynamical Vo programming using I2C from:
    • 1V up to 45V in 20mV monotonous steps
    • 1V up to 23V in 10mV monotonous steps
  • Peak current regulation control
  • Small voltage transition ripple overall operating modes
  • Dynamic output voltage tracking (digital PWM tracking input, analog tracking input)
    • Via I2C interface programming
  • Shut down quiescent current 3µA
  • Operating quiescent current 60µA
  • Drive (DRV) pin for dual role port power path
    • Push-Pull output for fast pMOS FET control
    • Configurable as charge pump driver stage for nMOS FET
  • Operation mode selection for high efficiency in light load and high load conditions:
    • Power save mode (Single Pulse/µSleep)
    • Automatic conduction mode
  • Integrated high voltage supply LDO
  • Auxiliary high voltage LDO for microcontroller supply
  • Integrated full-bridge gate drive
    • 2A peak current capability
    • Bootstrap over and undervoltage protection
    • Integrated boot-strap diode
  • Fixed frequency independent from operating mode (boost, buck-boost, buck)
    • Forced PWM mode selectable
    • Switching frequency from 100kHz to 2200kHz
    • External clock synchronization and clock output
  • Spread spectrum operation selectable
  • Average input or output current sensor
  • I2C programmable with diagnostics
  • Automotive temperature range (Tj = -40°C to 150°C)
  • 40-Pin WSON package with wettable flanks

  • Create a custom design using the LM34938-Q1 with the WEBENCH® Power Designer
  • Input range from 3.5V to 36V
  • Dynamical Vo programming using I2C from:
    • 1V up to 45V in 20mV monotonous steps
    • 1V up to 23V in 10mV monotonous steps
  • Peak current regulation control
  • Small voltage transition ripple overall operating modes
  • Dynamic output voltage tracking (digital PWM tracking input, analog tracking input)
    • Via I2C interface programming
  • Shut down quiescent current 3µA
  • Operating quiescent current 60µA
  • Drive (DRV) pin for dual role port power path
    • Push-Pull output for fast pMOS FET control
    • Configurable as charge pump driver stage for nMOS FET
  • Operation mode selection for high efficiency in light load and high load conditions:
    • Power save mode (Single Pulse/µSleep)
    • Automatic conduction mode
  • Integrated high voltage supply LDO
  • Auxiliary high voltage LDO for microcontroller supply
  • Integrated full-bridge gate drive
    • 2A peak current capability
    • Bootstrap over and undervoltage protection
    • Integrated boot-strap diode
  • Fixed frequency independent from operating mode (boost, buck-boost, buck)
    • Forced PWM mode selectable
    • Switching frequency from 100kHz to 2200kHz
    • External clock synchronization and clock output
  • Spread spectrum operation selectable
  • Average input or output current sensor
  • I2C programmable with diagnostics
  • Automotive temperature range (Tj = -40°C to 150°C)
  • 40-Pin WSON package with wettable flanks

  • Create a custom design using the LM34938-Q1 with the WEBENCH® Power Designer

The LM34938-Q1 is a four switch buck-boost controller. The device provides a regulated output voltage if the input voltage is higher, equal or lower than the adjusted output voltage. In power save mode the device supports very high efficiency over the complete operation range of the output. The output voltage and average current is dynamically programmable using the integrated I2C interface. The integrated DRV pin is used to control an optional disconnect FET for reverse polarity protection

LM34938-Q1 runs at a fixed switching frequency, which is set using the RT/SYNC pin. The switching frequency remains the same during buck, boost and buck-boost operation. The device maintains small mode transition ripple over all operating modes.

The LM34938-Q1 is a four switch buck-boost controller. The device provides a regulated output voltage if the input voltage is higher, equal or lower than the adjusted output voltage. In power save mode the device supports very high efficiency over the complete operation range of the output. The output voltage and average current is dynamically programmable using the integrated I2C interface. The integrated DRV pin is used to control an optional disconnect FET for reverse polarity protection

LM34938-Q1 runs at a fixed switching frequency, which is set using the RT/SYNC pin. The switching frequency remains the same during buck, boost and buck-boost operation. The device maintains small mode transition ripple over all operating modes.
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Technical documentation

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* Data sheet LM34938-Q1 Wide Vin 4 Switch Buck-Boost Controller with I2C for Automotive Wireless Charging datasheet PDF | HTML 10 Feb 2026
EVM User's guide LM34938-Q1 Buck-Boost Controller Evaluation Module PDF | HTML 12 Mar 2026

Design & development

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

Evaluation board

LM251772EVM-PD — LM251772 evaluation module

The LM251772EVM-PD demonstrates a flexible high-power buck-boost design using the LM251772. The evaluation module (EVM) is configured to operate from an input voltage range of 9V to 36V and to produce a regulated 5V to 48V output with up to a 5A load current. The EVM operates with a switching (...)
User guide: PDF | HTML
Not available on TI.com
Evaluation board

LM34938Q1EVM-HD — LM34938-Q1 evaluation module

The LM34938Q1EVM-HD demonstrates a flexible high power buck-boost design using the LM34938-Q1. The evaluation module is configured to operate from an input voltage range of 9V to 36V and to produce a regulated 15V to 28V output with up to a 50W output power. The EVM operates with a switching (...)
User guide: PDF | HTML
Not available on TI.com
Certification

LM34938Q1EVM-HD-DOC-CERT — LM34938Q1EVM-HD EU Declaration of Conformity (DoC)

LM34938Q1EVM-HD EU Declaration of Conformity (DoC)
Supported products & hardware

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VQFN (RHA) 40 Ultra Librarian
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