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Texas Instruments LMR36503RS3QRPERQ1
- Part No.:
- LMR36503RS3QRPERQ1
- Manufacturer:
- Texas Instruments
- Package:
- 9-PowerVFQFN
- Datasheet:
-
LMR36503RS3QRPERQ1.pdf
- Description:
- IC REG BUCK 3.3V 300MA 9VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,732
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Product details
Overview
LMR36503RS3QRPERQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter delivering 0.3 A at fixed 3.3 V output, operating from 3.0 V to 65 V input, with 4 µA switching quiescent current (VIN = 24 V → VOUT = 3.3 V), 2.0 mm × 2.0 mm HotRod™ VQFN-HR package, and integrated PGOOD flag - deployed in ADAS power rails requiring cold-crank resilience and low EMI.
For engineers reviewing the LMR36503RS3QRPERQ1 datasheet, LMR36503RS3QRPERQ1 pinout, LMR36503RS3QRPERQ1 application, or LMR36503RS3QRPERQ1 equivalent, key selection considerations include its RT-pin–programmable switching frequency (200 kHz–2.2 MHz), pseudo-random spread spectrum compliance with CISPR 25, internal compensation eliminating external loop components, and junction temperature range of –40°C to +150°C for under-hood deployment.
Technical Context
The LMR36503RS3QRPERQ1 uses peak current mode control with internal compensation and supports seamless FPWM-to-PFM transition for ultra-low light-load efficiency. Its RT pin enables precise frequency setting via external resistor, while the fixed 3.3 V output variant eliminates feedback resistors and simplifies layout.
It integrates a high-side MOSFET (RDS(on) = 560–920 mΩ) and low-side MOSFET (RDS(on) = 280–460 mΩ), features thermal shutdown (rising threshold 158–180°C), and delivers >70% efficiency at 5 mA load with VIN = 24 V and VOUT = 3.3 V - optimized for automotive systems enduring deep voltage sags during cold cranking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.0 V (falling threshold) to 65 V - sustains regulation during automotive cold-crank transients down to 2.45 V |
| Output Voltage | Fixed 3.3 V ±1.5% (FPWM mode) - eliminates external feedback divider and reduces BOM count |
| Max Output Current | 0.3 A continuous - supports low-power domain supplies for sensors, MCUs, and camera modules |
| Quiescent Current | 4 µA (switching, VIN = 24 V → 3.3 V) - enables always-on functionality without battery drain |
| Switching Frequency | Adjustable 200 kHz–2.2 MHz via RT pin - avoids AM band interference and enables compact magnetics |
| EMI Performance | Pseudo-random spread spectrum (±2% span, ~1.2 Hz pattern) - meets CISPR 25 Class 5 requirements without shielding |
| Package | VQFN-HR (RPE), 2.0 mm × 2.0 mm, 9-pin - wettable flanks enable automated optical inspection and robust solder joint reliability |
Pinout & Package
VQFN-HR (RPE) package: 2.0 mm × 2.0 mm body, 9-pin, wettable flanks, exposed thermal pad, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RT | Frequency programming input | Connects to GND (2.2 MHz), VCC (1 MHz), or resistor to GND for 200 kHz–2.2 MHz tuning - no MODE/SYNC function on this variant |
| 2 - PGOOD | Open-drain power-good flag | Asserts high when VOUT is within ±7% of nominal (106–110% / 93–96.5%) - replaces external supervisor IC |
| 3 - EN/UVLO | Enable and input undervoltage lockout | Wakes at 0.4 V, enables at 1.263 V (hysteresis 0.35 V) - supports direct connection to VIN for simple on/off control |
| 4 - VIN | Main input supply | Accepts 3.0–65 V; withstands 70 V transients - requires local ceramic bypass capacitor to GND |
| 5 - SW | Switch node | Connects to power inductor - carries high di/dt; must be routed with minimal loop area for EMI control |
| 6 - BOOT | High-side gate driver supply | Requires 100 nF ceramic capacitor between BOOT and SW - critical for proper high-side MOSFET turn-on |
| 7 - VCC | Internal LDO output | 3.15 V ±25 mV supply for control circuitry - decouple with 1 µF ceramic to GND; not for external loads |
| 8 - VOUT/BIAS | Fixed-output voltage node | Internally connected to 3.3 V regulator output - ties directly to output capacitor; no external feedback required |
| 9 - GND | Power ground | Thermal and electrical reference; must connect to CIN with short, wide trace - shared with exposed thermal pad |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PGOOD flag | Eliminates need for external reset supervisor IC and associated timing components in automotive domain controllers |
| Internal compensation | Reduces external component count to only input/output capacitors, inductor, and RT resistor - accelerates design validation |
| HotRod™ flip-chip packaging | Removes bond wires to minimize parasitic inductance - improves EMI performance and thermal resistance (RθJB = 26.1°C/W) |
| Ultra-low IQ in PFM mode | 4 µA at 24 V input enables >70% efficiency at 5 mA load - extends battery life in always-on vehicle subsystems |
| Pseudo-random spread spectrum | Reduces peak EMI by spreading energy across ±2% bandwidth - satisfies CISPR 25 without common-mode chokes or shielded inductors |
Applications
| Advanced Driver Assistance Systems (ADAS) | Body Electronics and Lighting |
|---|---|
Use Scenario: Powering radar sensor front-end ASICs and camera image signal processors in 12 V automotive architectures. IC Role / Device Role / Timing Role: Primary 3.3 V domain regulator supplying low-noise, stable voltage to analog front-ends and high-speed digital logic. Use Value: Withstands 2.45 V input sag during cold crank and maintains regulation - ensures uninterrupted sensor operation during engine start. | Use Scenario: Supplying interior LED lighting controllers and door module microcontrollers in battery-connected domains. IC Role / Device Role / Timing Role: Always-on 3.3 V buck converter enabling wake-on-LIN/CAN functionality with sub-µA standby draw. Use Value: 4 µA quiescent current prevents excessive battery discharge over weeks of vehicle dormancy - meets OEM parasitic load limits. |
| Infotainment and Cluster | Telematics Control Units (TCUs) |
Use Scenario: Generating 3.3 V bias for display timing controllers and audio codec interfaces in head-unit mainboards. IC Role / Device Role / Timing Role: Secondary regulated rail supporting noise-sensitive mixed-signal peripherals adjacent to high-speed DDR memory. Use Value: Spread spectrum and HotRod™ packaging reduce conducted/radiated emissions - avoids interference with AM/FM radio reception. | Use Scenario: Providing isolated 3.3 V supply for cellular modem baseband processors and GNSS receivers in telematics gateways. IC Role / Device Role / Timing Role: Input-transient-hardened DC/DC stage upstream of LDOs, ensuring clean power despite load-dump events. Use Value: 70 V absolute maximum input rating and thermal shutdown (158–180°C) protect against ISO 7637-2 pulse 5a/b surges and under-hood thermal stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR36503MSC3RPERQ1 | Same 3.3 V fixed output, but includes MODE/SYNC pin for external clock synchronization and PFM/FPWM mode selection | Required where system-level clock tree alignment or deterministic switching behavior is mandated (e.g., camera sync, radar chirp timing) | Select LMR36503MSC3RPERQ1 if external clock sync or programmable light-load mode control is needed; otherwise LMR36503RS3QRPERQ1 offers lower cost and simpler layout |
| LMR36506RS3QRPERQ1 | Pin-compatible 65 V, 0.6 A variant with identical package, pinout, and feature set - higher current capability only | Suitable for future-proofing or designs expecting increased load (e.g., adding CAN FD transceivers or extra sensors) | Choose LMR36506RS3QRPERQ1 only if >0.3 A output current is confirmed; LMR36503RS3QRPERQ1 provides optimal size/power trade-off for 300 mA loads |
Compared with LMR36503MSC3RPERQ1, LMR36503RS3QRPERQ1 trades external sync capability for reduced pin count and simplified biasing; compared with LMR36506RS3QRPERQ1, it delivers identical footprint and EMI performance at half the output current - optimizing solution size and cost for light-load automotive domains.
Availability
LMR36503RS3QRPERQ1 is available at Aetrix Electronics and suitable for advanced driver assistance systems (ADAS), body electronics and lighting, and infotainment and cluster applications requiring stable component supply, AEC-Q100 qualification, and long-term automotive lifecycle support.
Supply support for LMR36503RS3QRPERQ1 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 company designing analog ICs, embedded processors, and system solutions for industrial, automotive, and personal electronics markets.
The LMR36503-Q1 product line delivers compact, high-efficiency DC/DC converters optimized for automotive power domains - targeting cold-crank resilience, low EMI, and minimal external component count in space-constrained ECUs.
FAQ
What is the maximum input voltage rating for the LMR36503RS3QRPERQ1?
The LMR36503RS3QRPERQ1 has an absolute maximum input voltage rating of 70 V, with guaranteed operation from 3.0 V (falling threshold) to 65 V. This allows it to survive ISO 7637-2 load-dump pulses and maintain regulation during severe cold-crank conditions down to 2.45 V input - critical for automotive under-hood applications.
Does the LMR36503RS3QRPERQ1 require external compensation components?
No, the LMR36503RS3QRPERQ1 features internal compensation optimized for stability with minimal output capacitance. This eliminates external Type II or Type III compensation networks, reducing bill-of-materials count and PCB area - a key advantage over traditional buck controllers requiring external loop components.
How does the LMR36503RS3QRPERQ1 achieve low EMI performance?
The LMR36503RS3QRPERQ1 achieves low EMI through three integrated techniques: pseudo-random spread spectrum switching (±2% frequency dither), HotRod™ flip-chip packaging (eliminating bond-wire inductance), and optimized pin layout - collectively enabling CISPR 25 Class 5 compliance without external shielding or common-mode chokes.
What is the purpose of the RT pin on the LMR36503RS3QRPERQ1?
The RT pin on the LMR36503RS3QRPERQ1 sets the switching frequency from 200 kHz to 2.2 MHz using an external resistor to GND. Unlike MODE/SYNC variants, this pin does not support external clock synchronization - it is dedicated solely to frequency programming, enabling optimization for EMI, efficiency, or magnetics size.
Can the LMR36503RS3QRPERQ1 replace a 5-V fixed-output variant in an existing design?
No - the LMR36503RS3QRPERQ1 is factory-trimmed for fixed 3.3 V output and is not adjustable. To use 5 V output, select LMR36503RS5QRPERQ1 (same RT-pin variant, 5 V fixed) or LMR36503MSC5RPERQ1 (MODE/SYNC variant, 5 V fixed). Output voltage is set at wafer trim and cannot be modified post-manufacture.
LMR36503RS3QRPERQ1 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):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 300mA
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 9-VQFN-HR (2x2)
LMR36503RS3QRPERQ1 FAQ
1.How can I place an order for LMR36503RS3QRPERQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR36503RS3QRPERQ1 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 LMR36503RS3QRPERQ1 reliable?
The price and inventory of LMR36503RS3QRPERQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR36503RS3QRPERQ1 is usually 5 days.
3.What payment methods are accepted for LMR36503RS3QRPERQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR36503RS3QRPERQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR36503RS3QRPERQ1?
LMR36503RS3QRPERQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR36503RS3QRPERQ1 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 LMR36503RS3QRPERQ1?
For technical support, including LMR36503RS3QRPERQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR36503RS3QRPERQ1 requirements.
6.How does Aetrix verify that LMR36503RS3QRPERQ1 is sourced from the original manufacturer or authorized distributors?
All LMR36503RS3QRPERQ1 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 LMR36503RS3QRPERQ1 meets industry standards.
7.What is the process for return or replacement of LMR36503RS3QRPERQ1?
All LMR36503RS3QRPERQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LMR36503RS3QRPERQ1, 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 LMR36503RS3QRPERQ1 part is unused and in its original packaging.
Return procedure for LMR36503RS3QRPERQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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