LMR36503-Q1

ACTIVE

Automotive 3-V to 65-V, 0.3-A buck converter optimized for size and light load efficiency

Product details

Rating Automotive Operating temperature range (°C) -40 to 150 TI functional safety category Functional Safety-Capable Topology Buck Type Converter Iout (max) (A) 0.3 Vin (min) (V) 3 Vin (max) (V) 65 Switching frequency (min) (kHz) 200 Switching frequency (max) (kHz) 2200 Features Enable, Fixed Output, Forced PWM, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Soft Start Fixed, Spread Spectrum, Synchronous Rectification, Wettable flanks package EMI features Low parasitic Hotrod packaging, Spread Spectrum Control mode current mode Vout (min) (V) 1 Vout (max) (V) 28 Iq (typ) (µA) 4 Duty cycle (max) (%) 99
Rating Automotive Operating temperature range (°C) -40 to 150 TI functional safety category Functional Safety-Capable Topology Buck Type Converter Iout (max) (A) 0.3 Vin (min) (V) 3 Vin (max) (V) 65 Switching frequency (min) (kHz) 200 Switching frequency (max) (kHz) 2200 Features Enable, Fixed Output, Forced PWM, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Soft Start Fixed, Spread Spectrum, Synchronous Rectification, Wettable flanks package EMI features Low parasitic Hotrod packaging, Spread Spectrum Control mode current mode Vout (min) (V) 1 Vout (max) (V) 28 Iq (typ) (µA) 4 Duty cycle (max) (%) 99
VQFN-HR (RPE) 9 4 mm² 2 x 2
  • AEC-Q100-qualified for automotive applications:
    • Device temperature grade 1: –40°C to +125°C, TA
  • Functional Safety-Capable
  • >70% efficiency at 5 mA
    • 4 µA IQ (switching) at 24 VIN to 3.3 VOUT (fixed output option)
  • Miniature solution size and low component cost
    • 2-mm × 2-mm HotRod™ package with wettable flanks
    • Internal compensation
  • Designed for automotive applications:
    • Junction temperature range –40°C to +150°C
    • Pseudo-random spread spectrum compatible with CISPR 25 EMI standard
    • Wide input voltage range: 3.0 V (falling threshold) to 65 V
    • Adjustable, 3.3-V and 5-V fixed output voltage options available
    • Synchronizable with MODE/SYNC pin variant
    • Adjustable FSW: 200 kHz to 2.2 MHz with RT pin variant
    • Pin compatible with LMR36506-Q1 (65 V, 600 mA)
  • AEC-Q100-qualified for automotive applications:
    • Device temperature grade 1: –40°C to +125°C, TA
  • Functional Safety-Capable
  • >70% efficiency at 5 mA
    • 4 µA IQ (switching) at 24 VIN to 3.3 VOUT (fixed output option)
  • Miniature solution size and low component cost
    • 2-mm × 2-mm HotRod™ package with wettable flanks
    • Internal compensation
  • Designed for automotive applications:
    • Junction temperature range –40°C to +150°C
    • Pseudo-random spread spectrum compatible with CISPR 25 EMI standard
    • Wide input voltage range: 3.0 V (falling threshold) to 65 V
    • Adjustable, 3.3-V and 5-V fixed output voltage options available
    • Synchronizable with MODE/SYNC pin variant
    • Adjustable FSW: 200 kHz to 2.2 MHz with RT pin variant
    • Pin compatible with LMR36506-Q1 (65 V, 600 mA)

The LMR36503-Q1 is the industry’s smallest 65 V, 0.3 A synchronous step-down DC/DC converter in 2-mm x 2-mm HotRod™ package. This easy-to-use converter can handle input voltage transients up to 70 V, provide excellent EMI performance and support fixed 3.3 V, 5 V and other adjustable output voltages.

The LMR36503-Q1 uses peak current mode control architecture with internal compensation and maintains stable operation with minimal output capacitance. The wide input operating range of the LMR36503-Q1 helps it remain functional during a deep input voltage sag condition, making it an excellent choice for automotive applications withstanding severe cold crank start impulses. The PGOOD flag in the LMR36503-Q1 provides precise indication of the output voltage status, eliminating the requirement for an external supervisor. A seamless transition from FPWM to PFM, with an ultra-low standby quiescent current allows the LMR36503-Q1 to support much higher system efficiency at low output loads. The MODE/SYNC pin variant helps to synchronize the LMR36503-Q1 to an external clock. With the right resistor selection, the LMR36503-Q1 RT pin variant can also be externally programmed to any desired switching frequency of operation. The rich feature set of the LMR36503-Q1 is designed to simplify implementation for a wide range of automotive end equipments.

The LMR36503-Q1 is the industry’s smallest 65 V, 0.3 A synchronous step-down DC/DC converter in 2-mm x 2-mm HotRod™ package. This easy-to-use converter can handle input voltage transients up to 70 V, provide excellent EMI performance and support fixed 3.3 V, 5 V and other adjustable output voltages.

The LMR36503-Q1 uses peak current mode control architecture with internal compensation and maintains stable operation with minimal output capacitance. The wide input operating range of the LMR36503-Q1 helps it remain functional during a deep input voltage sag condition, making it an excellent choice for automotive applications withstanding severe cold crank start impulses. The PGOOD flag in the LMR36503-Q1 provides precise indication of the output voltage status, eliminating the requirement for an external supervisor. A seamless transition from FPWM to PFM, with an ultra-low standby quiescent current allows the LMR36503-Q1 to support much higher system efficiency at low output loads. The MODE/SYNC pin variant helps to synchronize the LMR36503-Q1 to an external clock. With the right resistor selection, the LMR36503-Q1 RT pin variant can also be externally programmed to any desired switching frequency of operation. The rich feature set of the LMR36503-Q1 is designed to simplify implementation for a wide range of automotive end equipments.

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Technical documentation

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Type Title Date
* Data sheet LMR36503-Q1 3-V to 65-V, 0.3-A Synchronous Buck Converter Optimized for Size and Light Load Efficiency datasheet (Rev. B) PDF | HTML 22 Sep 2020
Selection guide Buck Converter Quick Reference Guide (Rev. B) 08 Apr 2021
Functional safety information LMR3650x-Q1 Functional Safety, FIT Rate, Failure Mode Distribution and Pin FMA PDF | HTML 26 Oct 2020
EVM User's guide LMR36506MSCEVM User’s Guide (Rev. A) 19 May 2020
Technical article Optimizing flip-chip IC thermal performance in automotive designs PDF | HTML 11 Dec 2019

Design & development

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

Evaluation board

LMR36503MSCEEVM — LMR360503E-Q1 evaluation module 

The LMR36503E-Q1 is a 65V DC/DC, 0.3A buck regulator that features synchronous rectification to achieve high conversion efficiency in a small footprint. The LMR36503E-Q1 evaluation module (EVM) operates over a wide input voltage range of 5.5V to 65V to provide a regulated 5V output up to 0.3A load (...)

User guide: PDF | HTML
Not available on TI.com
Evaluation board

LMR36506EVM — Automotive 3-V to 65-V, 0.6-A ultra-small synchronous buck converter evaluation module

The LMR36506MSCEVM evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LMR36506-Q1 synchronous step-down converter. The LMR36503-Q1 can also be evaluated with LMR36506MSCEVM.

User guide: PDF
Not available on TI.com
Simulation model

LMR36503MSC-Q1 PSpice Unencrypted Transient Model

SNVMC16.ZIP (528 KB) - PSpice Model
Simulation model

LMR36503MSC3-Q1 PSpice Unencrypted Transient Model

SNVMC17.ZIP (530 KB) - PSpice Model
Simulation model

LMR36503MSC5-Q1 PSpice Unencrypted Transient Model

SNVMC28.ZIP (524 KB) - PSpice Model
Simulation model

LMR36503RS3-Q1 PSpice Unencrypted Transient Model

SNVMC26.ZIP (517 KB) - PSpice Model
Simulation model

LMR36503RS5-Q1 PSpice Unencrypted Transient Model

SNVMC27.ZIP (538 KB) - PSpice Model
Simulation model

LMR36506R PSpice Unencrypted Transient Model

SNVMBW4.ZIP (166 KB) - PSpice Model
Calculation tool

LMR36503E-Q1-CALC LMR36503, LMR36503-Q1, LMR36503E-Q1 converter quickstart tool

Welcome to the quickstart design tool for the LMR36503, LMR36503-Q1, and LMR36503E-Q1. This tool facilitates and assists the power supply engineer with the design of a DC/DC buck regulator based on the above converter family to meet application requirements.
Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC converters (integrated FET)
LMR36503E-Q1 Automotive 3V to 65V, 0.3A buck converter LMR36503 3-V to 65-V, 0.3-A ultra-small synchronous buck converter with 6 μA IQ LMR36503-Q1 Automotive 3-V to 65-V, 0.3-A buck converter optimized for size and light load efficiency
Package Pins CAD symbols, footprints & 3D models
VQFN-HR (RPE) 9 Ultra Librarian

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