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Texas Instruments LMR51450SDRRR
- Part No.:
- LMR51450SDRRR
- Manufacturer:
- Texas Instruments
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LMR51450SDRRR.pdf
- Description:
- IC REG BUCK ADJ 5A 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,874
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Product details
Overview
LMR51450SDRRR from Texas Instruments is a 36-V, 5-A synchronous step-down DC/DC converter with 25 µA quiescent current, ±1.0% reference voltage tolerance at 25°C, 75 ns minimum on-time, and adjustable 200 kHz–1.1 MHz switching frequency-designed for rugged industrial power conditioning in PLCs and test instrumentation.
For engineers reviewing the LMR51450SDRRR datasheet, LMR51450SDRRR pinout, LMR51450SDRRR application, or LMR51450SDRRR equivalent, key selection criteria include PFM-mode light-load efficiency, integrated thermal shutdown and hiccup-mode short-circuit protection, WSON-12 package layout compatibility, and precision enable input for system-level UVLO sequencing.
Technical Context
The LMR51450SDRRR uses fixed-frequency peak-current mode control with internal compensation, enabling stable regulation across wide VIN (4–36 V) and load (0–5 A) ranges without external loop components. Its PFM variant dynamically reduces switching frequency at light loads to maintain >90% efficiency down to 1 mA output.
It integrates high-side (78 mΩ) and low-side (45 mΩ) MOSFETs, supports adjustable frequency via RT pin resistor, and features open-drain PGOOD with 2.0% hysteresis and 3.1 ms delay-ensuring reliable system reset during output faults or startup transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4 V to 36 V - supports unregulated industrial rails including 12 V, 24 V, and 36 V battery or bus supplies. |
| Output Current | 5 A continuous - delivers full rated load without derating at TJ ≤ 125°C with standard PCB copper. |
| Quiescent Current | 25 µA - enables >10-year battery life in always-on industrial sensors and metering applications. |
| Reference Voltage | 0.8 V ±1.0% at 25°C - ensures ±1.5% output voltage accuracy over temperature and line/load with 1% FB resistors. |
| Switching Frequency | 200 kHz to 1.1 MHz - selectable via RT pin; 500 kHz default allows compact 2.2 µH inductors and low EMI filtering. |
| Min On-Time | 75 ns typical - supports high VIN-to-VOUT ratios (e.g., 24 V → 3.3 V) without frequency foldback below 500 kHz. |
| Thermal Shutdown | 160°C shutdown / 140°C recovery - protects against sustained overload or poor heatsinking in enclosed enclosures. |
Pinout & Package
LMR51450SDRRR is housed in a thermally enhanced 3.0 mm × 3.0 mm WSON-12 (DRR) package with exposed DAP for low RθJC(bot) = 6.3°C/W and optimized thermal path to PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1,2,3) | Power switch node | Connects to inductor; carries full AC ripple current and high di/dt-requires short, wide trace and local ground pour. |
| BOOT (4) | High-side gate driver supply | Requires 100 nF ceramic capacitor to SW; critical for high-side FET turn-on; sensitive to layout parasitics. |
| PG (5) | Open-drain power-good flag | Asserts low if FB voltage deviates >2% from 0.8 V; needs 10–100 kΩ pullup to logic rail ≤20 V. |
| RT (6) | Frequency setting input | Resistor to AGND sets fSW: 31.6 kΩ = 495 kHz; open = 500 kHz; short to GND = 1 MHz. |
| FB (7) | Voltage feedback input | Senses output via resistor divider; 0.8 V reference; avoid floating or grounding-noise-sensitive analog node. |
| AGND (8) | Analog ground reference | Zero-volt reference for FB, EN, RT, PG; must tie to PGND via small net-tie near device. |
| EN (9) | Precision enable input | 1.1–1.4 V threshold; supports external UVLO via resistor divider; never leave floating. |
| VIN (10,11,12) | Main input power | Three parallel pins reduce IR drop and improve thermal performance; connect CIN as close as possible. |
| PGND/DAP (13) | Power ground & thermal pad | Internally connected to low-side FET source; must be soldered to large PCB copper area for thermal and EMI control. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode-reduces BOM count, improves efficiency by 3–5% at full load. |
| Internal compensation | Enables stable operation with any ceramic output capacitor ≥22 µF-no external Type II/III network required. |
| Frequency spread spectrum (PFM) | ±10% oscillator dither reduces peak EMI by 5–8 dB without compromising transient response. |
| Hiccup-mode short-circuit protection | Shuts down for 96 ms after fault detection-prevents thermal runaway while allowing automatic recovery. |
| Low dropout mode operation | Maintains regulation down to VIN − VOUT ≈ 1.5 V at 5 A-supports high-ratio conversion without foldback. |
Applications
| PLC Power Supply | Test Instrumentation |
|---|---|
Use Scenario: Provides isolated 5 V/3.3 V rails for I/O modules and microcontrollers in programmable logic controllers operating from 24 V DC field buses. IC Role / Device Role / Timing Role: Primary buck regulator delivering clean, regulated 5 V at up to 5 A with PGOOD signaling to FPGA configuration logic. Use Value: 25 µA IQ extends backup battery runtime; ±1.0% VREF ensures ADC reference stability across –40°C to 85°C ambient. | Use Scenario: Powers analog front-end, DACs, and MCU in portable multimeters and signal generators requiring ultra-low noise and tight load regulation. IC Role / Device Role / Timing Role: Main DC/DC stage converting 9–36 V battery or adapter input to 3.3 V with minimal output ripple in FPWM mode. Use Value: 75 ns min on-time enables 24 V → 3.3 V conversion at 500 kHz; internal soft-start (3.2–7.2 ms) prevents inrush-induced voltage sag. |
| Industrial Appliance Control | DCS Field Interface |
Use Scenario: Supplies 5 V to motor drivers, touch panels, and communication ICs in washing machines and HVAC controllers with wide input variation. IC Role / Device Role / Timing Role: High-reliability buck converter handling 4–36 V input transients and 150°C junction temperature during extended bake cycles. Use Value: Thermal shutdown at 160°C and 150°C max TJ rating ensure safe operation in sealed, high-temp enclosures. | Use Scenario: Generates 3.3 V for HART modems and isolation barriers in distributed control system field terminals powered from 24 V loop supplies. IC Role / Device Role / Timing Role: Regulator with precision enable input used for power sequencing-enabling analog circuitry only after digital core is stable. Use Value: Adjustable EN UVLO (via resistor divider) prevents brownout resets during 24 V loop dips; PGOOD confirms rail integrity before enabling isolators. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR51450FNDRRR | FPWM mode only (no PFM); no spread spectrum; same 5 A rating and WSON-12 package. | Better suited for noise-sensitive analog systems requiring constant-frequency operation and lower output ripple. | Select when strict EMI spectral mask compliance or low-noise ADC/DAC biasing is required over light-load efficiency. |
| TPS54561RGTT | 6 A rating, 3.5–60 V input, 150 µA IQ, SOIC-16 package; no integrated PGOOD or spread spectrum. | Higher input voltage range and current capability-but larger footprint and higher quiescent current limits battery use. | Choose for 48 V industrial buses or designs needing >5 A margin; accept trade-off of larger size and reduced light-load efficiency. |
Compared with LMR51450FNDRRR, the LMR51450SDRRR offers superior light-load efficiency via PFM but sacrifices constant-frequency behavior; versus TPS54561RGTT, it provides smaller solution size and 6× lower IQ, though at lower maximum input voltage and current headroom.
Availability
LMR51450SDRRR is available at Aetrix Electronics and suitable for PLC power supplies, test instrumentation, and industrial appliance control requiring stable component supply, long-term manufacturability, and automotive-grade reliability under thermal stress.
Supply support for LMR51450SDRRR 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 and embedded processing technologies, with decades of expertise in power management IC design and industrial-grade reliability validation.
The LMR514x0 product line was developed specifically for ruggedized industrial DC/DC conversion-emphasizing wide VIN range, low IQ, integrated protection, and ease-of-use in space-constrained, thermally demanding environments.
FAQ
What is the maximum output current capability of the LMR51450SDRRR?
The LMR51450SDRRR delivers up to 5 A of continuous DC output current under recommended operating conditions (TJ ≤ 125°C, adequate PCB copper, and proper thermal layout). Derating applies above 125°C junction temperature or at high switching frequencies-see Section 7.2 of the datasheet for detailed current vs. temperature curves.
Does the LMR51450SDRRR support adjustable output voltage?
Yes, the LMR51450SDRRR supports fully adjustable output voltage from 0.8 V to 28 V using an external resistor divider on the FB pin. The internal 0.8 V reference enables precise regulation-TI recommends 1% tolerance, low-TC resistors with RFBT between 10 kΩ and 1 MΩ for optimal noise immunity and light-load efficiency.
What protection features are integrated into the LMR51450SDRRR?
The LMR51450SDRRR includes cycle-by-cycle current limiting, hiccup-mode short-circuit protection, thermal shutdown (160°C trip), VIN undervoltage lockout (3.9 V rising), and open-drain PGOOD monitoring. These features operate autonomously without external components-ensuring robust operation in industrial environments with variable input and load conditions.
Can the LMR51450SDRRR be used in battery-powered applications?
Yes, the LMR51450SDRRR is well-suited for battery-powered applications due to its 25 µA quiescent current in PFM mode and wide 4–36 V input range-supporting single-cell LiFePO₄ up to 4-series Li-ion or 24 V lead-acid systems. Its low IQ enables multi-year operation in always-on sensor nodes and remote monitoring devices.
What is the recommended PCB layout practice for the LMR51450SDRRR thermal pad?
The LMR51450SDRRR's PGND/DAP pin (Pin 13) must be soldered to a solid, low-thermal-resistance copper plane-ideally ≥200 mm² with ≥4 thermal vias (0.3 mm diameter) connecting to inner or bottom-layer ground planes. This achieves RθJA(Eff) ≈ 23°C/W per TI EVM data and prevents thermal throttling at full 5 A load.
LMR51450SDRRR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- 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 ~ 1.1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-WSON (3x3)
LMR51450SDRRR FAQ
1.How can I place an order for LMR51450SDRRR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR51450SDRRR 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 LMR51450SDRRR reliable?
The price and inventory of LMR51450SDRRR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR51450SDRRR is usually 5 days.
3.What payment methods are accepted for LMR51450SDRRR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR51450SDRRR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR51450SDRRR?
LMR51450SDRRR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR51450SDRRR 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 LMR51450SDRRR?
For technical support, including LMR51450SDRRR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR51450SDRRR requirements.
6.How does Aetrix verify that LMR51450SDRRR is sourced from the original manufacturer or authorized distributors?
All LMR51450SDRRR 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 LMR51450SDRRR meets industry standards.
7.What is the process for return or replacement of LMR51450SDRRR?
All LMR51450SDRRR units undergo pre-shipment inspection (PSI). If there is an issue with LMR51450SDRRR, 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 LMR51450SDRRR part is unused and in its original packaging.
Return procedure for LMR51450SDRRR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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