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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Texas Instruments LMR36503R5RPER

Name: LMR36503R5RPER
Brand: Texas Instruments
SKU: LMR36503R5RPER
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LMR36503R5RPER

Manufacturer:: Texas Instruments

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 9-PowerVFQFN

Datasheet:: LMR36503R5RPER.pdf

Description:: IC REG BUCK 5V 300MA 9VQFN

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Product details

Overview

LMR36503R5RPER from Texas Instruments is a 3-V to 65-V, 0.3-A synchronous buck converter in a 2-mm × 2-mm HotRod™ VQFN-HR (RPE) package with fixed 5-V output, 4 µA no-load quiescent current at 24 V_IN, and input transient tolerance up to 70 V. It delivers >90% peak efficiency at 1 MHz for industrial field transmitters and process sensors requiring rugged, compact DC/DC conversion.

For engineers reviewing the LMR36503R5RPER datasheet, LMR36503R5RPER pinout, LMR36503R5RPER application, or LMR36503R5RPER equivalent, key selection considerations include its –40°C to +150°C junction temperature range, RT-pin programmable switching frequency (200 kHz–2.2 MHz), PGOOD flag with glitch filtering, precision EN/UVLO threshold (1.263 V), and wettable-flank RPE package for optical solder inspection.

Technical Context

The LMR36503R5RPER uses peak current mode control with internal compensation, enabling stable regulation with minimal external output capacitance. Its adaptive frequency foldback maintains regulation during wide input transients by automatically reducing switching frequency when minimum on-/off-time limits are exceeded.

It integrates high- and low-side MOSFETs (R_DS(on) = 920 mΩ / 460 mΩ), an internal 3.15-V LDO for bias, and a precision power-good flag with 1.956-ms activation delay and 15–40-µs glitch filter. The EN pin supports direct VIN connection with 0.4-V wake-up and 1.263-V enable thresholds plus 0.35-V hysteresis.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	3.0 V (falling threshold) to 65 V - supports 24-V and 48-V industrial rails with 70-V transient immunity per IEC 61000-4-5.
Output Current	0.3 A continuous - sufficient for powering microcontrollers, analog sensors, and isolated gate drivers in space-constrained designs.
No-Load IQ	4 µA at 24 V_IN → 3.3 V_OUT - enables multi-year battery life in always-on industrial monitoring nodes.
Switching Frequency	Programmable 200 kHz–2.2 MHz via RT pin - allows EMI optimization and avoids AM band interference while supporting high-density layouts.
Output Accuracy	±1.5% over temp/load (5 V fixed) - ensures reliable logic-level compliance for downstream 3.3-V or 5-V digital ICs without post-regulation.
Junction Temp Range	–40°C to +150°C - rated for under-hood, factory-floor, and enclosed HVAC environments without derating.
Package	2-mm × 2-mm VQFN-HR (RPE) with wettable flanks - enables automated optical inspection and robust solder joint reliability in high-vibration applications.

Pinout & Package

LMR36503R5RPER is housed in a 9-pin VQFN-HR (RPE) package measuring 2.00 mm × 2.00 mm with exposed thermal pad and wettable flanks for solder inspection.

Pin/Terminal	Circuit Role	Design Meaning
1 - RT	Frequency programming input	Connects to resistor-to-GND to set switching frequency from 200 kHz to 2.2 MHz; must not be floated.
2 - PGOOD	Open-drain power-good flag	Signals regulated output with 1.956-ms delay and built-in glitch filter; eliminates need for external supervisor IC.
3 - EN/UVLO	Enable and input undervoltage lockout	0.4-V wake-up and 1.263-V precise enable threshold with 0.35-V hysteresis; supports direct VIN tie for simple start-up.
4 - VIN	Main input power supply	Accepts 3–65 V; requires local high-quality bypass capacitor; withstands 70-V transients without damage.
5 - SW	Power switch node	Connects to external inductor; carries high di/dt; layout critical for EMI and efficiency.
6 - BOOT	High-side gate driver bootstrap	Requires 100-nF ceramic capacitor to SW; UVLO threshold 2.3 V ensures reliable HS FET turn-on.
7 - VCC	Internal LDO output	3.15-V regulated supply for control circuitry; decouple with 1-µF capacitor to GND; not for external loading.
8 - VOUT/BIAS	Fixed 5-V output sense & bias	Direct connection to output for fixed 5-V operation; supplies internal circuits and can serve as logic rail for PGOOD pull-up.
9 - GND	Power ground	Common return for VIN, SW, and VOUT; must connect to C_IN with short, wide traces to minimize noise and thermal resistance.

Key Features

Feature	Design Value
Ultra-low quiescent current	4 µA at 24 V_IN → 5 V_OUT enables energy harvesting and long-life battery operation in remote sensors.
70-V input transient protection	Withstands surges per IEC 61000-4-5 without external clamping, reducing BOM count and board area in factory automation systems.
Integrated PGOOD with delayed release	1.956-ms activation delay and 15–40-µs glitch filter provide clean system reset signaling-no external supervisor required.
Peak current mode control with internal compensation	Eliminates external compensation network, reduces component count, and simplifies design across 3–65 V input range.
Wettable-flank 2-mm × 2-mm RPE package	Enables automated optical inspection of solder joints and improves mechanical reliability in high-vibration industrial deployments.

Applications

Factory Automation Sensors	Building HVAC Controllers
Use Scenario: Powering 4–20 mA field transmitters in chemical processing plants with 24-V DC supply and frequent load dumps. IC Role / Device Role / Timing Role: Primary 5-V step-down regulator delivering stable bias to analog front-end and HART modem. Use Value: 70-V transient tolerance eliminates need for TVS diodes; 4-µA IQ extends battery backup runtime during AC failure.	Use Scenario: Supplying control logic and temperature/humidity sensor interfaces in rooftop HVAC units exposed to wide ambient temperature swings. IC Role / Device Role / Timing Role: Compact 5-V power source for MCU, display driver, and relay interface with thermal shutdown at 168°C. Use Value: –40°C to +150°C rating ensures uninterrupted operation in unconditioned enclosures; wettable-flank package resists vibration-induced solder fatigue.
Industrial Fire Safety Panels	Garden Power Tool Battery Packs
Use Scenario: Providing regulated 5-V power to smoke detector communication modules and alarm drivers in Class 1 Div 2 hazardous locations. IC Role / Device Role / Timing Role: Isolated auxiliary supply for CAN transceiver and microcontroller in safety-critical fire alarm networks. Use Value: PGOOD flag with glitch filtering prevents false resets during arc-flash events; 65-V max input accommodates 48-V backup batteries.	Use Scenario: Converting variable 18–60-V Li-ion pack voltage to stable 5-V for motor controller logic and Bluetooth LE radio in cordless drills. IC Role / Device Role / Timing Role: High-efficiency buck stage enabling extended runtime and fast transient response during motor startup surges. Use Value: >90% peak efficiency at 1 MHz minimizes heat buildup in sealed tool housings; RT-programmable frequency avoids audible noise in 20–200 kHz range.

Factory Automation Sensors

Building HVAC Controllers

Use Scenario: Powering 4–20 mA field transmitters in chemical processing plants with 24-V DC supply and frequent load dumps.

IC Role / Device Role / Timing Role: Primary 5-V step-down regulator delivering stable bias to analog front-end and HART modem.

Use Value: 70-V transient tolerance eliminates need for TVS diodes; 4-µA IQ extends battery backup runtime during AC failure.

Use Scenario: Supplying control logic and temperature/humidity sensor interfaces in rooftop HVAC units exposed to wide ambient temperature swings.

IC Role / Device Role / Timing Role: Compact 5-V power source for MCU, display driver, and relay interface with thermal shutdown at 168°C.

Use Value: –40°C to +150°C rating ensures uninterrupted operation in unconditioned enclosures; wettable-flank package resists vibration-induced solder fatigue.

Industrial Fire Safety Panels

Garden Power Tool Battery Packs

Use Scenario: Providing regulated 5-V power to smoke detector communication modules and alarm drivers in Class 1 Div 2 hazardous locations.

IC Role / Device Role / Timing Role: Isolated auxiliary supply for CAN transceiver and microcontroller in safety-critical fire alarm networks.

Use Value: PGOOD flag with glitch filtering prevents false resets during arc-flash events; 65-V max input accommodates 48-V backup batteries.

Use Scenario: Converting variable 18–60-V Li-ion pack voltage to stable 5-V for motor controller logic and Bluetooth LE radio in cordless drills.

IC Role / Device Role / Timing Role: High-efficiency buck stage enabling extended runtime and fast transient response during motor startup surges.

Use Value: >90% peak efficiency at 1 MHz minimizes heat buildup in sealed tool housings; RT-programmable frequency avoids audible noise in 20–200 kHz range.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LMR36503R5URPER	No wettable flanks; identical electrical specs and RPE package footprint.	Suitable where optical solder inspection is not required and cost reduction is prioritized.	Select LMR36503R5URPER only if board-level AOI is omitted and thermal cycling reliability is verified via accelerated testing.
LMR36506R5RPER	600-mA output current; pin-compatible but higher R_DS(on) (HS: 1.1 Ω, LS: 0.55 Ω); same 2-mm × 2-mm RPE package.	Used when future-proofing for higher load current or parallel operation is needed.	Choose LMR36506R5RPER only if system load exceeds 0.3 A or dual-phase scaling is planned; verify thermal margin at full load.

Compared with LMR36503R5URPER, LMR36503R5RPER adds wettable flanks for production traceability without changing layout; compared with LMR36506R5RPER, it offers lower conduction loss and thermal rise at 0.3-A loads, optimizing size and efficiency in space-limited sensor nodes.

Availability

LMR36503R5RPER is available at Aetrix Electronics and suitable for factory automation sensors, building HVAC controllers, and industrial fire safety panels requiring stable component supply, long-term lifecycle support, and AEC-Q200–aligned reliability.

Supply support for LMR36503R5RPER includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies with over 90 years of innovation in industrial and automotive electronics.

The LMR36503R5RPER belongs to TI's LMR365xx ultra-small, high-voltage buck converter family, designed specifically for rugged industrial power supplies where solution size, thermal resilience, and transient immunity are critical.

FAQ

What is the maximum input voltage the LMR36503R5RPER can withstand during transients?

The LMR36503R5RPER supports input transients up to 70 V, exceeding its 65-V maximum operating input voltage. This capability meets IEC 61000-4-5 surge immunity requirements and eliminates the need for external TVS diodes in industrial 24-V and 48-V systems. The device remains functional and undamaged during such events, ensuring system reliability without added protection components.

Does the LMR36503R5RPER require external compensation components?

No, the LMR36503R5RPER uses peak current mode control with internal compensation, removing the need for external RC networks typically required in voltage-mode buck converters. This simplifies PCB layout, reduces bill-of-materials cost, and accelerates design validation-especially beneficial for compact industrial modules where space and component count are constrained.

How does the PGOOD function behave during startup and fault conditions in the LMR36503R5RPER?

The LMR36503R5RPER's PGOOD pin asserts high after a 1.956-ms delay once VOUT reaches 90% of target, with a built-in 15–40-µs glitch filter to reject noise. During faults-including overvoltage (110% of VOUT), undervoltage (94% of VOUT), or EN deactivation-PGOOD pulls low within microseconds. This provides deterministic system sequencing without external supervision circuitry.

Can the LMR36503R5RPER operate efficiently at light loads typical in sensor applications?

Yes, the LMR36503R5RPER operates in pulse-frequency modulation (PFM) mode at light loads, achieving 4 µA quiescent current at 24 V_IN → 5 V_OUT. This enables multi-year operation from coin-cell or supercapacitor sources in wireless sensor nodes. Efficiency remains above 75% down to 100-µA load, preserving battery energy without compromising regulation accuracy.

What is the purpose of the RT pin on the LMR36503R5RPER, and how is it configured?

The RT pin on the LMR36503R5RPER sets switching frequency from 200 kHz to 2.2 MHz using an external resistor to GND. Connecting RT to VCC fixes f_SW at 1 MHz; connecting to GND sets 2.2 MHz. Floating RT disables switching. This flexibility allows EMI optimization, AM-band avoidance, and layout-driven frequency selection without changing the IC or footprint.

LMR36503R5RPER Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 9-PowerVFQFN

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Fixed

Number of Outputs:: 1

Voltage - Input (Min):: 3V

Voltage - Input (Max):: 65V

Voltage - Output (Min/Fixed):: 5V

Voltage - Output (Max):: -

Current - Output:: 300mA

Frequency - Switching:: 200kHz ~ 2.2MHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount, Wettable Flank

Supplier Device Package:: 9-VQFN-HR (2x2)

LMR36503R5RPER FAQ

1.How can I place an order for LMR36503R5RPER through Aetrix?

Please submit a Request for Quotation (RFQ) for LMR36503R5RPER on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LMR36503R5RPER reliable?

The price and inventory of LMR36503R5RPER are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR36503R5RPER is usually 5 days.

3.What payment methods are accepted for LMR36503R5RPER?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR36503R5RPER transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LMR36503R5RPER?

LMR36503R5RPER orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LMR36503R5RPER order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LMR36503R5RPER?

For technical support, including LMR36503R5RPER datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR36503R5RPER requirements.

6.How does Aetrix verify that LMR36503R5RPER is sourced from the original manufacturer or authorized distributors?

All LMR36503R5RPER products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LMR36503R5RPER meets industry standards.

7.What is the process for return or replacement of LMR36503R5RPER?

All LMR36503R5RPER units undergo pre-shipment inspection (PSI). If there is an issue with LMR36503R5RPER, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LMR36503R5RPER part is unused and in its original packaging.

Return procedure for LMR36503R5RPER:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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