Automotive Grade, 3-65V Wide Vin, Current Mode Synchronous Boost with Disconnection Switch Control


Product details


Vin (Min) (V) 3 Vin (Max) (V) 65 Vout (Min) (V) 3 Vout (Max) (V) 100 Regulated outputs (#) 1 Switching frequency (Min) (kHz) 50 Switching frequency (Max) (kHz) 1000 Iq (Typ) (mA) 4 Features Enable, Frequency Synchronization Duty cycle (Max) (%) 100 Type Controller Rating Automotive Operating temperature range (C) -40 to 125 open-in-new Find other Boost controllers (external switch)

Package | Pins | Size

HTSSOP (PWP) 20 42 mm² 6.5 x 6.4 open-in-new Find other Boost controllers (external switch)


  • AEC-Q100 Qualified with the following results:
    • Device Temperature Grade 1: –40°C to +125°C
      Ambient Operating Temperature Range
    • Device HBM ESD Classification Level 2
    • Device CDM ESD Classification Level C6
  • Maximum Input Voltage: 65 V
  • Min Input Voltage: 3.0 V (4.5 V for startup)
  • Output Voltage Up to 100 V
  • Bypass (VOUT = VIN) Operation
  • 1.2-V Reference with ±1.0% Accuracy
  • Free-Run/Synchronizable up to 1 MHz
  • Peak Current Mode Control
  • Robust Integrated 3-A Gate Drivers
  • Adaptive Dead-Time Control
  • Optional Diode Emulation Mode
  • Programmable Cycle-by-Cycle Current Limit
  • Programmable Line UVLO
  • Programmable Soft-Start
  • Thermal Shutdown Protection
  • Low Shutdown Quiescent Current: 9 µA
  • Programmable Slope Compensation
  • Programmable Skip Cycle Mode Reduces
    Standby Power
  • Supports External VCC Bias Supply Option
  • Load Disconnection in Shutdown Mode (True
  • Inrush Current Limiting
  • Hiccup Mode Short Circuit/Overload Protection
  • Circuit Breaker Function
  • Capable of Input Transient Suppression
  • Capable of Reverse Battery Protection
  • Thermally Enhanced 20-Pin HTSSOP
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The LM5121 is a synchronous boost controller intended for high-efficiency, high-power boost regulator applications. The control method is based upon peak current mode control. Current mode control provides inherent line feed-forward, cycle-by-cycle current limiting and ease of loop compensation.

The switching frequency is programmable up to 1 MHz. Higher efficiency is achieved using two robust N-channel MOSFET gate drivers with adaptive dead-time control. A user-selectable diode emulation mode enables discontinuous mode operation for improved efficiency at light load conditions.

The LM5121 provides disconnection switch control which completely disconnects the output from the input during an output short or a shutdown condition. During start-up sequence, inrush current is limited by the disconnection switch control.

An internal charge pump allows 100% duty cycle operation of the high-side synchronous switch (Bypass operation). Additional features include thermal shutdown, frequency synchronization, hiccup mode current limit and adjustable line undervoltage lockout.

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Technical documentation

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Type Title Date
* Datasheet LM5121/-Q1 Wide Input Synchronous Boost Controller with Disconnection Switch Control datasheet (Rev. C) Jun. 14, 2016
Technical articles How to add overvoltage protection to a synchronous boost controller Sep. 17, 2018
Application notes Designing the front-end DC/DC conversion stage to withstand automotive transient Jan. 18, 2017
Technical articles Exploiting current-mode control for wide Vin DC/DC conversion Aug. 14, 2014
User guides LM5121EVM Evaluation Module Aug. 23, 2013

Design & development

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

Hardware development

document-generic User guide
The LM5121EVM evaluation module (EVM) provides the design engineer with a fully functional synchronous boost converter to evaluate the Texas Instruments LM5121 synchronous boost controller IC including disconnection switch control. The EVM provides 12V output at up to 2A current from a 3.0V (5.7V (...)
  • 3V to 12V input range (5.7V for start-up)
  • 12V/2A output
  • 250kHz switching frequency
  • Programmable light load operation
  • Inrush current limit, short circuit protection

Design tools & simulation

SNVM505A.ZIP (115 KB) - PSpice Model
SNVM962.ZIP (7 KB) - PSpice Model
SNVMA47A.ZIP (53 KB) - TINA-TI Spice Model
SNVMA48.TSC (192 KB) - TINA-TI Reference Design

Reference designs

ADAS 8-Channel Sensor Fusion Hub Reference Design with Two 4-Gbps Quad Deserializers
TIDA-01413 — This sensor fusion hub reference design allows the connection of up to four 2-megapixel cameras and up to four radar modules over coaxial cable. This design utilizes these coaxial cables to provide power, backchannel communication, and clock synchronization to the sensors. The two 4 Gbps FPD-Link (...)
document-generic Schematic document-generic User guide

CAD/CAE symbols

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HTSSOP (PWP) 20 View options

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