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Texas Instruments LMR51440SQDRRRQ1
- Part No.:
- LMR51440SQDRRRQ1
- Manufacturer:
- Texas Instruments
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LMR51440SQDRRRQ1.pdf
- Description:
- IC REG BUCK ADJ 4A 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,369
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Product details
Overview
LMR51440SQDRRRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter delivering up to 4A continuous output current, supporting 4V–36V input range, ±1.0% reference voltage accuracy at 25°C, 75ns minimum on-time, and 25µA quiescent current in PFM mode - deployed in ADAS power rails and infotainment head units.
For engineers reviewing the LMR51440SQDRRRQ1 datasheet, LMR51440SQDRRRQ1 pinout, LMR51440SQDRRRQ1 application, or LMR51440SQDRRRQ1 equivalent, key selection considerations include its PFM-only operation (no FPWM), spread-spectrum EMI reduction, precision enable UVLO configuration, and WSON-12 thermal performance with RθJA = 47.4°C/W.
Technical Context
The LMR51440SQDRRRQ1 implements fixed-frequency peak-current mode control with internal compensation, enabling stable regulation using minimal external components. Its PFM-only operation eliminates light-load switching frequency variation while maintaining high efficiency down to 1mA load.
It integrates high-side (78mΩ) and low-side (45mΩ) MOSFETs, supports adjustable switching frequency (200kHz–1MHz) via RT resistor, and features cycle-by-cycle current limiting, hiccup-mode short-circuit protection, and thermal shutdown at 160°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports direct connection to automotive battery (cold-crank down to 4V) without pre-regulator |
| Output Current | 4A continuous - rated for sustained operation under 125°C ambient with proper PCB copper area |
| Quiescent Current | 25µA in PFM mode - enables >10-year battery standby life in always-on vehicle modules |
| Reference Voltage | 0.8V ±1.0% at 25°C - ensures ≤±1.5% total output voltage error over temperature and line/load |
| Switching Frequency | 200kHz–1MHz (RT-programmable) - allows trade-off between inductor size (higher fSW) and conduction loss (lower fSW) |
| Min On-Time | 75ns typical - enables 5V→1.2V conversion at 400kHz with ≥3% duty cycle margin |
| Thermal Shutdown | 160°C trip / 140°C recovery - provides robust overtemperature protection with 20°C hysteresis to prevent oscillation |
Pinout & Package
Package: WSON-12 (DRR), 3.0mm × 3.0mm, exposed thermal pad (PGND/DAP), moisture sensitivity level 2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1,2,3) | Power switch node | Connects to inductor; carries full AC switching current - requires low-inductance layout and thermal relief to DAP |
| BOOT (4) | High-side gate driver supply | Requires 100nF ceramic capacitor to SW; critical for high-side FET turn-on reliability |
| PG (5) | Open-drain power-good flag | Asserts low if FB voltage deviates >12% above or >10% below target - needs 10kΩ–100kΩ pull-up |
| RT (6) | Frequency setting input | Resistor-to-AGND sets fSW; open = 440kHz, short-to-GND = 1MHz - no floating allowed |
| FB (7) | Voltage feedback input | Senses output via resistor divider; 0.8V reference - never short to ground during operation |
| AGND (8) | Analog ground reference | Zero-volt reference for internal circuits; must tie to PGND with small net-tie, not shared plane |
| EN (9) | Precision enable input | 1.1V–1.4V threshold - supports external UVLO divider for battery undervoltage cutoff |
| VIN (10,11,12) | Main power input | Three parallel pins reduce IR drop and improve thermal dissipation - connect CIN directly here |
| PGND/DAP (13) | Power ground & thermal pad | Internally connected to low-side FET source; must be soldered to large PCB copper area for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for –40°C to +125°C ambient operation - meets automotive electronics reliability requirements |
| Spread-spectrum frequency modulation | ±10% dithering around center frequency - reduces peak EMI by >10dB for CISPR 25 Class 5 compliance |
| Integrated synchronous rectification | 78mΩ HS / 45mΩ LS MOSFETs - eliminates external diode, improves full-load efficiency by 8–12% vs. asynchronous design |
| Internal soft-start | 5ms typical ramp time - prevents inrush current and output overshoot during startup |
| Adjustable UVLO via EN pin | Configurable turn-on/off thresholds using resistor divider - enables system-level brown-out protection |
Applications
| ADAS Camera Power Supply | Infotainment Head Unit Core Rail |
|---|---|
Use Scenario: Powers image sensor and ISP in forward-facing ADAS camera module requiring clean, low-noise 1.2V/2A rail. IC Role / Device Role / Timing Role: Primary DC/DC regulator converting 12V battery to 1.2V; operates in PFM mode during vehicle sleep to minimize standby drain. Use Value: 25µA IQ extends battery hold-up time beyond 14 days; 75ns min on-time supports required 1.2V output at 400kHz switching. | Use Scenario: Generates 3.3V/3A supply for SoC, display interface, and USB charging circuitry in automotive head unit. IC Role / Device Role / Timing Role: Main buck converter with spread-spectrum EMI control to meet stringent CISPR 25 radiated emissions limits near sensitive RF receivers. Use Value: ±1.0% VREF and internal compensation ensure <±2% total output error across temperature; WSON-12 footprint saves >30% board area vs. SOIC-8 alternatives. |
| Body Control Module (BCM) Microcontroller Rail | Automotive Cluster Display Backlight Driver Bias |
Use Scenario: Supplies 5V/2A to MCU, CAN transceiver, and LIN interface in door module or seat controller. IC Role / Device Role / Timing Role: High-reliability point-of-load regulator with thermal shutdown and hiccup-mode short-circuit protection for unattended operation. Use Value: 160°C thermal shutdown with 20°C hysteresis prevents latch-up during sustained overload; VIN UVLO (3.9V rise / 3.4V fall) avoids brownout resets. | Use Scenario: Provides stable 5V bias for LED backlight driver IC in digital instrument cluster with wide ambient temperature swing. IC Role / Device Role / Timing Role: Secondary regulated rail decoupled from main 12V bus; uses precision enable for synchronized power sequencing with display controller. Use Value: Adjustable EN threshold enables coordinated startup with cluster MCU; PG flag signals rail readiness to display firmware during boot. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR51440FSQDRRRQ1 | FPWM variant - constant 440kHz switching at all loads; no PFM mode | Better for noise-sensitive analog circuits requiring fixed-frequency ripple; higher light-load IQ (≈120µA) | Select when low-output-voltage ripple and tight regulation at light load outweigh efficiency concerns |
| TPS544B20RTWR | 4A, 4.5V–18V input, 3.3V/5V fixed outputs; no spread spectrum; smaller 3mm × 2mm QFN | Limited to lower VIN range; lacks automotive qualification and functional safety documentation | Consider only for non-automotive industrial applications where AEC-Q100 is not required |
Compared with LMR51440SQDRRRQ1, the FS variant trades light-load efficiency for ripple stability, while TPS544B20RTWR offers compactness but omits automotive qualification, spread spectrum, and precision enable - making LMR51440SQDRRRQ1 the sole choice for AEC-Q100-compliant PFM-optimized designs.
Availability
LMR51440SQDRRRQ1 is available at Aetrix Electronics and suitable for automotive ADAS camera modules, infotainment head units, and body control modules requiring stable component supply with full AEC-Q100 traceability and long-term production support.
Supply support for LMR51440SQDRRRQ1 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 headquartered in Dallas, Texas, designing and manufacturing analog and embedded processing chips for industrial, automotive, and personal electronics markets.
The LMR514x0-Q1 product line delivers highly integrated, AEC-Q100-qualified buck converters optimized for space-constrained automotive subsystems requiring low IQ, spread-spectrum EMI control, and robust protection features.
FAQ
What is the maximum input voltage rating for the LMR51440SQDRRRQ1?
The LMR51440SQDRRRQ1 has an absolute maximum input voltage of 38V across VIN to PGND, with recommended operating range of 4V to 36V. This allows direct connection to 12V and 24V automotive batteries, including cold-crank transients down to 4V and load-dump spikes up to 36V without external clamping.
Does the LMR51440SQDRRRQ1 support forced PWM (FPWM) mode?
No, the LMR51440SQDRRRQ1 is the PFM-only variant of the family. It automatically enters pulse-frequency modulation at light loads to maximize efficiency. The FPWM version is the LMR51440FSQDRRRQ1, which maintains constant switching frequency across all load conditions.
How is the switching frequency set on the LMR51440SQDRRRQ1?
The LMR51440SQDRRRQ1 uses the RT pin to set switching frequency from 200kHz to 1MHz via an external resistor to AGND. For example, a 34.8kΩ resistor yields 400kHz; leaving RT open defaults to 440kHz; shorting RT to GND sets 1MHz. The RT pin must never be left floating.
What thermal performance can be expected from the LMR51440SQDRRRQ1 in a standard PCB layout?
In a typical 2-layer PCB with 2oz copper and 1in² thermal pad area, the LMR51440SQDRRRQ1 achieves RθJA ≈ 47.4°C/W. With optimized thermal vias and internal layer copper pours, junction-to-ambient resistance drops to ~23°C/W (per TI EVM data), enabling 4A continuous output at +85°C ambient.
Can the LMR51440SQDRRRQ1 be used without an external feedback resistor divider?
No - the LMR51440SQDRRRQ1 requires an external resistor divider from VOUT to FB to set output voltage, as it uses a fixed 0.8V internal reference. The FB pin has no internal resistors; omitting the divider results in undefined output voltage and potential damage due to unregulated operation.
LMR51440SQDRRRQ1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- LMR514x0-Q1
- Package/Case:
- 12-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 28V
- Current - Output:
- 4A
- Frequency - Switching:
- 200kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-WSON (3x3)
LMR51440SQDRRRQ1 FAQ
1.How can I place an order for LMR51440SQDRRRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR51440SQDRRRQ1 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 LMR51440SQDRRRQ1 reliable?
The price and inventory of LMR51440SQDRRRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR51440SQDRRRQ1 is usually 5 days.
3.What payment methods are accepted for LMR51440SQDRRRQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR51440SQDRRRQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR51440SQDRRRQ1?
LMR51440SQDRRRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR51440SQDRRRQ1 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 LMR51440SQDRRRQ1?
For technical support, including LMR51440SQDRRRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR51440SQDRRRQ1 requirements.
6.How does Aetrix verify that LMR51440SQDRRRQ1 is sourced from the original manufacturer or authorized distributors?
All LMR51440SQDRRRQ1 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 LMR51440SQDRRRQ1 meets industry standards.
7.What is the process for return or replacement of LMR51440SQDRRRQ1?
All LMR51440SQDRRRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LMR51440SQDRRRQ1, 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 LMR51440SQDRRRQ1 part is unused and in its original packaging.
Return procedure for LMR51440SQDRRRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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