3.5-V to 36-V, 2.5-A step-down voltage converter with spread spectrum


Product details


Vin (Min) (V) 3.5 Vin (Max) (V) 36 Vout (Min) (V) 1 Vout (Max) (V) 20 Iout (Max) (A) 2.5 Iq (Typ) (uA) 23 Switching frequency (Min) (kHz) 250 Switching frequency (Max) (kHz) 2200 Features Enable, Fixed Output, Forced PWM, Frequency Synchronization, Light Load Efficiency, Power Good, Soft Start Fixed, Spread Spectrum, Synchronous Rectification, UVLO Fixed Operating temperature range (C) -40 to 150 Rating Automotive Regulated outputs (#) 1 open-in-new Find other Buck converters (integrated switch)

Package | Pins | Size

HTSSOP (PWP) 16 32 mm² 5 x 6.4 WSON (DRR) 12 9 mm² 3 x 3 open-in-new Find other Buck converters (integrated switch)


  • AEC-Q100-Qualified for automotive applications
    • Device temperature grade 1: –40°C to +125°C ambient operating temperature
  • Functional Safety-Capable
    • Documentation available to aid functional safety system design
  • Supports automotive system requirements
    • Input voltage range: 3.5 V to 36 V
    • Short minimum on-time of 50 ns
    • Good EMI performance Pseudo-random spread spectrum Compatible with CISPR 25
    • Low operating quiescent current of 23 µA
    • Junction temperature range –40°C to +150°C
  • High design flexibility
    • Pin selectable VOUT: 3.3 V, 5 V, adjustable 1 V to 20 V
    • Pin compatible with LM63610/LM63635 (1A, 3.25 A)
    • Pin selectable frequency: 400 kHz, 2.1 MHz, adjustable 250 kHz to 2200 kHz
    • Pin selectable FPWM, AUTO, sync modes
    • TSSOP: Thermally-enhanced package
    • WSON: For space-constrained applications
  • Small solution size
    • As small as: 10 mm x 10 mm for 2.5 A, 2.2 MHz with WSON package
    • Highly integrated solution
    • Low component count
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The LM636x5D-Q1 regulator is an easy-to-use, synchronous, step-down DC/DC converter designed for rugged automotive applications. The LM636x5D-Q1 can drive up to 1.5-A or 2.5-A of load current from an input of up to 36 V. The converter has high light load efficiency and output accuracy in a small solution size. Features such as a RESET flag and precision enable provide both flexible and easy-to-use solutions for a wide range of applications. Automatic frequency foldback at light load improves efficiency while maintaining tight load regulation. Integration eliminates many external components and provides a pinout designed for simple PCB layout. Protection features include thermal shutdown, input undervoltage lockout, cycle-by-cycle current limit, and hiccup short-circuit protection. LM636x5D-Q1is available in the HTSSOP 16-pin power package, with PowerPAD™, and the WSON 12-pin power package.


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Sample availability

Preproduction samples in DRR (WSON) package (PLM63625DQB1DRRQ1) are available. Request now

Technical documentation

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Type Title Date
* Data sheet LM636x5-Q1 3.5-V to 36-V, 1.5-A, and 2.5-A Automotive Step-down Voltage Converter datasheet (Rev. F) Mar. 16, 2021
Functional safety information LM636xx-Q1 Functional Safety, FIT Rate, Failure Mode Distribution and Pin FMA (Rev. C) Jun. 10, 2021
Selection guide Buck Converter Quick Reference Guide (Rev. B) Apr. 08, 2021
Technical article Powering levels of autonomy: a quick guide to DC/DC solutions for SAE autonomy levels Nov. 18, 2020
Application note PCB Thermal Design Tips for Automotive DC/DC Converters Nov. 12, 2020
White paper Streamlining Functional Safety Certification in Automotive and Industrial Jun. 09, 2020
White paper 簡化汽車及工業領域的功 能安全認證 Jun. 09, 2020
White paper 자동차 및 산업 분야의 기능적 안전성 인증 간소화 Jun. 09, 2020
White paper Demystifying Input Supply Current in DC/DC Regulators:From Shutdown to Full Load May 18, 2020
Application note Working with Inverting Buck-Boost Converters (Rev. A) May 14, 2020
Certificate LM63625EVM EU Declaration of Conformity (DoC) May 05, 2020
User guide LM63625DRREVM EVM User's Guide Jan. 10, 2020
User guide LM63625EVM EVM User’s Guide (Rev. A) Oct. 23, 2019
Technical article How to manage coefficient of thermal expansion in automotive designs Jun. 18, 2019
Technical article Minimize the impact of the MLCC shortage on your power application Mar. 29, 2019

Design & development

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Hardware development

document-generic User guide
The LM63625 evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LM63625 synchronous step-down converter.
  • Integrated synchronous rectification
  • Low operating quiescent current
  • High efficiency at light loads
  • Low minimum on-time
document-generic User guide
The LM63625QDRREVM evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LM63635 synchronous step-down converter.
  • Integrated synchronous rectification
  • Low operating quiescent current
  • High efficiency at light loads
  • Low minimum on-time

Software development

SNVC239A.ZIP (1622 KB)

Design tools & simulation

SNVMBR5.ZIP (98 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
  • (...)

Reference designs

High-power density reference design for automotive vehicle-to-everything (V2X) power
PMP22648 — This reference design provides the system rails for automotive vehicle-to-everything power. A 5-V bus is generated by the off-battery buck converter (LM63625-Q1), and this supplies all the point-of-load devices. The bus converter switches at 2.1 MHz, and the load converters (TPS628501-Q1) switch at (...)
document-generic Schematic document-generic User guide
2-MHz synchronous 5-V buck reference design
PMP30794 — This reference design uses a tiny automotive buck converter to support a 5-V rail by input voltage range 6.5-V up to 32-Vpk surge. The layout and design are optimized to pass CISPR-25. The design is equipped with a two-stage input filter to minimize conducted emissions and a solid ground plane to (...)
document-generic Schematic document-generic User guide
Automotive multi-rail power supply for driving monitoring system reference design
PMP30785 — This reference design shows the performance of a non-isolated automotive power supply for a driving monitoring system for the electronic control unit (ECU). The reference design includes our power portfolio with nine power sockets.
document-generic Schematic document-generic User guide
Efficient, low-heat, CISPR 25 class 5-compliant power reference design for infotainment display
PMP22030 — This reference design is focused on the power tree for an automotive infotainment display unit covering various power supply rails including two off-battery converters providing 5.0-V and 3.3-V, and intermediary system rails of 1.8-V and 1.1-V. The test results demonstrate high efficiency, low heat (...)
document-generic Schematic document-generic User guide

CAD/CAE symbols

Package Pins Download
HTSSOP (PWP) 16 View options
WSON (DRR) 12 View options

Ordering & quality

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