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Texas Instruments LMR51450SQDRRRQ1
- Part No.:
- LMR51450SQDRRRQ1
- Manufacturer:
- Texas Instruments
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LMR51450SQDRRRQ1.pdf
- Description:
- IC REG BUCK ADJ 5A 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,694
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Product details
Overview
LMR51450SQDRRRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter delivering up to 5A continuous output current, supporting 4V–36V input range, ±1.0% reference voltage accuracy at 25°C, and 25µA quiescent current in PFM mode - deployed in ADAS power rails and infotainment head units.
For engineers reviewing the LMR51450SQDRRRQ1 datasheet, LMR51450SQDRRRQ1 pinout, LMR51450SQDRRRQ1 application, or LMR51450SQDRRRQ1 equivalent, key selection considerations include its WSON-12 package thermal performance (RθJA = 47.4°C/W), 75ns minimum on-time for high VIN/low VOUT operation, FPWM/PFM mode flexibility, and integrated cycle-by-cycle current limiting with hiccup recovery.
Technical Context
The LMR51450SQDRRRQ1 employs fixed-frequency peak-current mode control with internal compensation, enabling stable regulation using minimal external components. Its dual-mode operation supports PFM for light-load efficiency (down to 25µA IQ) and FPWM for constant-frequency, low-ripple performance across full load.
It integrates high-side (78mΩ RDS-ON) and low-side (45mΩ RDS-ON) NMOS switches, features precision enable with adjustable UVLO via resistor divider, and delivers open-drain PGOOD with 2.0% hysteresis and 3.1ms delay after regulation recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports direct battery connection across cold-crank (4.5V) to load-dump (36V) conditions in automotive systems. |
| Output Current | 5A continuous - sustains full-rated load at TJ ≤ 150°C with proper PCB copper and thermal relief. |
| Reference Voltage | 0.8V ±1.0% at 25°C - enables accurate 3.3V/5V/12V outputs with standard 1% feedback resistors. |
| Quiescent Current | 25µA (PFM mode) - extends battery runtime in always-on vehicle modules like telematics or body controllers. |
| Switching Frequency | 200kHz–1MHz, adjustable via RT resistor - allows trade-off between EMI filtering size (lower fSW) and inductor volume (higher fSW). |
| Min On-Time | 75ns typical - enables 5V→1.2V conversion at 24V input without frequency foldback. |
| Protection Features | Cycle-by-cycle current limit, hiccup-mode short-circuit protection, thermal shutdown (160°C trip), and VIN UVLO (3.9V rising) - ensures robust fault handling in unregulated automotive supplies. |
Pinout & Package
Package: WSON-12 (3.00mm × 3.00mm, exposed DAP), RoHS-compliant, moisture sensitivity level 2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1,2,3) | Power switch node | Internally connects high-side drain and low-side source; requires low-inductance path to power inductor and input/output capacitors. |
| BOOT (4) | Bootstrap supply | Connects 100nF ceramic capacitor to SW; enables high-side gate drive above VIN during switching. |
| PG (5) | Open-drain power-good | Asserts low when FB voltage deviates >2% from 0.8V; requires 10kΩ–100kΩ pull-up to logic rail ≤20V. |
| RT (6) | Frequency setting | Resistor to AGND sets fSW from 200kHz–1MHz; open = ~440kHz, short-to-GND = 1MHz. |
| FB (7) | Voltage feedback input | Senses resistor divider output; 0.8V reference sets VOUT = 0.8V × (1 + RFBT/RFBB); never short to ground. |
| AGND (8) | Analog ground reference | Zero-volt reference for internal circuits; must be tied to PGND via small net-tie, not shared with noisy power traces. |
| EN (9) | Precision enable | Active-high logic input; 1.25V threshold enables startup; resistor divider from VIN creates system UVLO. |
| VIN (10,11,12) | Main input supply | Three parallel power pins reduce IR drop and improve thermal conduction; connect CIN as close as possible. |
| PGND/DAP (13) | Power ground & thermal pad | Internal connection to low-side FET source and exposed thermal pad; must be soldered to large PCB copper pour for RθJB = 20.7°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for –40°C to +125°C ambient operation - meets automotive reliability and stress-test requirements. |
| Integrated synchronous rectification | Eliminates external Schottky diode; reduces conduction loss and improves full-load efficiency by ≥5% vs. asynchronous designs. |
| Internal compensation | Removes need for external Type-II/III compensation network - cuts BOM count and simplifies layout validation. |
| Frequency spread spectrum | Dithers switching frequency ±10% - lowers peak EMI amplitude to ease CISPR 25 Class 5 compliance. |
| Adjustable soft-start | Fixed 3.2–7.2ms internal ramp - prevents inrush current and output overshoot during power-up. |
Applications
| ADAS Camera Power Supply | Infotainment Head Unit Core Rail |
|---|---|
Use Scenario: Powers image sensor and ISP in forward-facing ADAS camera module operating from 12V battery with cold-crank transients. IC Role / Device Role / Timing Role: Primary 3.3V/5A buck regulator supplying digital core and interface logic; maintains regulation during 4.5V–36V input excursions. Use Value: 25µA IQ extends sleep-mode battery life; 75ns tON-MIN supports 3.3V output from 24V input without foldback; PFM mode achieves >85% efficiency at 10mA load. | Use Scenario: Generates 5V main rail for SoC, display driver, and USB charging circuitry in automotive head unit with variable thermal loading. IC Role / Device Role / Timing Role: High-current synchronous buck converter with FPWM option to suppress audible noise and minimize output ripple during audio playback. Use Value: 45mΩ low-side RDS-ON reduces conduction loss at 5A; thermal shutdown (160°C) protects against prolonged high-ambient operation; WSON-12 DAP enables <25°C/W board-level θJA with 2oz copper. |
| Body Control Module (BCM) Subsystem | Cluster Display Backlight Driver |
Use Scenario: Supplies 3.3V to microcontroller, CAN transceiver, and sensor interface in door module with intermittent wake events. IC Role / Device Role / Timing Role: Always-on buck regulator with precision EN pin enabling programmable UVLO for battery state-of-charge management. Use Value: Adjustable EN threshold (via RENT/RENB) sets 9.2V system UVLO to prevent deep discharge; 3µA shutdown current minimizes parasitic drain. | Use Scenario: Provides stable 12V rail to LED backlight strings in digital instrument cluster exposed to wide ambient temperature swings. IC Role / Device Role / Timing Role: Wide-input buck converter regulating 12V output from 7V–16V vehicle bus; uses PGOOD to sequence backlight enable after MCU initialization. Use Value: ±1.0% VREF ensures consistent LED brightness across temperature; PGOOD delay (3.1ms) avoids false resets during VOUT settling; hiccup protection prevents latch-up during shorted LED string faults. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR51450FSQDRRRQ1 | FPWM-only variant; no PFM mode; fixed 1MHz default frequency with RT open | Better suited for noise-sensitive applications requiring constant fSW and tight VOUT ripple | Select when low-light-load ripple matters more than ultra-low IQ; same pinout and package. |
| TPS54560QDGQRQ1 | 5.5A max, 3.5V–60V input, 115µA IQ, external compensation required | Higher input range supports 48V architectures; higher IQ limits always-on use cases | Choose for 48V battery systems or where design flexibility via external compensation outweighs simplicity. |
Compared with LMR51450FSQDRRRQ1, the LMR51450SQDRRRQ1 offers superior light-load efficiency but slightly higher output ripple; versus TPS54560QDGQRQ1, it provides lower IQ and simpler layout at the cost of reduced input voltage headroom and fixed compensation.
Availability
LMR51450SQDRRRQ1 is available at Aetrix Electronics and suitable for automotive ADAS, infotainment head units, and body electronics requiring stable component supply with AEC-Q100 compliance and long-term production support.
Supply support for LMR51450SQDRRRQ1 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 specializing in analog and embedded processing technologies, with leadership in power management ICs for automotive, industrial, and consumer markets.
The LMR514x0-Q1 product line delivers compact, high-efficiency synchronous buck converters optimized for automotive subsystems demanding AEC-Q100 qualification, low IQ, and robust protection - targeting ADAS, infotainment, and body electronics.
FAQ
What is the maximum output current capability of the LMR51450SQDRRRQ1 under continuous operation?
The LMR51450SQDRRRQ1 delivers 5A continuous output current when operated within its recommended junction temperature range (–40°C to +150°C), with adequate PCB copper area and thermal relief. Derating applies above 100°C ambient or at high switching frequencies; refer to the thermal derating curves in Section 6.4 of the datasheet for precise limits based on layout and airflow.
Does the LMR51450SQDRRRQ1 support both PFM and FPWM modes, and how is mode selection implemented?
Yes, the LMR51450SQDRRRQ1 operates in PFM mode by default to maximize light-load efficiency. It does not support FPWM mode - that functionality is exclusive to the LMR51450FSQDRRRQ1 variant. Mode selection is determined at manufacture; no external pin or register configures PFM/FPWM behavior on the LMR51450SQDRRRQ1.
What is the purpose of the RT pin on the LMR51450SQDRRRQ1, and what resistance value sets 400kHz switching frequency?
The RT pin sets the switching frequency via an external resistor to AGND. For 400kHz operation, a 34.8kΩ resistor is specified per Table 7-1 in the datasheet. The RT pin must not be left floating; open-circuit defaults to ~440kHz, while shorting to GND forces 1MHz. Frequency dithering (±10%) is enabled by default to reduce EMI peaks.
How does the enable (EN) pin function on the LMR51450SQDRRRQ1, and can it be used for system-level undervoltage lockout?
The EN pin is a precision enable input with 1.25V typical turn-on threshold and 1.0V typical turn-off threshold. It supports system-level UVLO by connecting a resistor divider between VIN, EN, and AGND - allowing programmable startup/shutdown voltages (e.g., 9.2V UVLO). The pin must never be left floating and cannot exceed VIN + 0.3V.
What thermal metrics apply to the LMR51450SQDRRRQ1 in its WSON-12 (DRR) package, and how does the exposed DAP affect thermal performance?
The LMR51450SQDRRRQ1 in WSON-12 has RθJA = 47.4°C/W (JEDEC standard), RθJB = 20.7°C/W (junction-to-board), and RθJC(bot) = 6.3°C/W (junction-to-case bottom). The exposed DAP (pin 13) must be soldered to a large internal/external copper pour to achieve rated RθJB; omitting thermal vias or insufficient copper increases junction temperature and risks thermal shutdown at full load.
LMR51450SQDRRRQ1 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:
- 5A
- 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)
LMR51450SQDRRRQ1 FAQ
1.How can I place an order for LMR51450SQDRRRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR51450SQDRRRQ1 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 LMR51450SQDRRRQ1 reliable?
The price and inventory of LMR51450SQDRRRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR51450SQDRRRQ1 is usually 5 days.
3.What payment methods are accepted for LMR51450SQDRRRQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR51450SQDRRRQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR51450SQDRRRQ1?
LMR51450SQDRRRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR51450SQDRRRQ1 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 LMR51450SQDRRRQ1?
For technical support, including LMR51450SQDRRRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR51450SQDRRRQ1 requirements.
6.How does Aetrix verify that LMR51450SQDRRRQ1 is sourced from the original manufacturer or authorized distributors?
All LMR51450SQDRRRQ1 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 LMR51450SQDRRRQ1 meets industry standards.
7.What is the process for return or replacement of LMR51450SQDRRRQ1?
All LMR51450SQDRRRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LMR51450SQDRRRQ1, 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 LMR51450SQDRRRQ1 part is unused and in its original packaging.
Return procedure for LMR51450SQDRRRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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