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Texas Instruments LMR51406YFDBVR
- Part No.:
- LMR51406YFDBVR
- Manufacturer:
- Texas Instruments
- Package:
- SOT-23-6
- Datasheet:
-
LMR51406YFDBVR.pdf
- Description:
- IC REG BUCK ADJ 600MA SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:2,940
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Product details
Overview
LMR51406YFDBVR from Texas Instruments is a 4V–42V input, 0.6A synchronous buck DC/DC converter with fixed 1.1MHz switching frequency and forced PWM (FPWM) operation. It integrates high- and low-side MOSFETs, internal compensation, and precision enable in a 6-pin SOT-23 package. Designed for industrial power conditioning, it delivers regulated output voltage in PLC analog I/O modules and smart meter auxiliary rails.
For engineers reviewing the LMR51406YFDBVR datasheet, LMR51406YFDBVR pinout, LMR51406YFDBVR application, or LMR51406YFDBVR equivalent, key selection criteria include its 1.1MHz FPWM mode for low output ripple, ±1.5% reference tolerance, 80ns minimum on-time, hiccup-mode short-circuit protection, and –40°C to 150°C junction temperature range.
Technical Context
The LMR51406YFDBVR employs fixed-frequency peak-current mode control with internal slope compensation and fully integrated power stage. Its FPWM operation maintains constant 1.1MHz switching across all load conditions, enabling tight output voltage regulation and predictable EMI behavior without light-load frequency variation.
It features monotonic start-up with prebiased output, precision enable with adjustable UVLO via external divider, and dual overcurrent protection: cycle-by-cycle peak current limiting (0.8–1.4A) and valley current limiting (0.62–0.98A), plus hiccup-mode recovery for sustained shorts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 42V - supports wide industrial unregulated rails including 24V and 36V systems. |
| Output Current | 0.6A continuous - sufficient for powering microcontrollers, ADCs, and isolated gate drivers in compact designs. |
| Switching Frequency | 1.1MHz (FPWM) - enables use of sub-2.2µH inductors and reduces output capacitor size vs. 400kHz variants. |
| Reference Voltage | 0.8V ±1.5% - sets output accuracy; used with external resistor divider to configure VOUT from 0.8V to 28V. |
| Min ON Time | 80ns - supports high step-down ratios (e.g., 24V→3.3V) without frequency foldback at light loads. |
| Junction Temp Range | –40°C to +150°C - rated for harsh environments including motor control enclosures and outdoor metering. |
| Thermal Resistance | RθJA = 147.8°C/W (JEDEC 4-layer board) - requires thermal-aware PCB layout with GND copper pour under exposed pad. |
Pinout & Package
LMR51406YFDBVR is housed in a 6-pin SOT-23 (DBV) package measuring 2.90mm × 2.80mm, with an exposed thermal pad connected internally to GND. The package supports reflow soldering per JEDEC J-STD-020 and is optimized for minimal board area in space-constrained industrial modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CB | Bootstrap capacitor connection | Connects 100nF X7R ceramic capacitor to SW; supplies gate drive voltage for internal high-side MOSFET. |
| GND | Power ground | Internal source node of low-side FET; must tie directly to system ground and CIN/COUT ground planes with short traces. |
| FB | Feedback input | Analog input sensing output voltage via resistor divider; 0.2nA leakage ensures stable regulation with high-value dividers. |
| EN | Enable control | Precision analog input (1.1–1.36V threshold); supports system-level UVLO configuration or logic-level sequencing. |
| VIN | Main input supply | Connects to 4–42V source and input bypass capacitors; powers internal LDO and high-side driver circuitry. |
| SW | Switching node | Drain of high-side FET / source of low-side FET; connects directly to power inductor; high dv/dt node requiring tight layout. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode; achieves >90% efficiency at 5V/0.6A with minimal BOM count. |
| Internal compensation | Removes need for external Type-II/III compensation network; simplifies design and improves stability across capacitor ESR variations. |
| Hiccup-mode short-circuit protection | Shuts down for 150ms after 256 consecutive current-limit cycles; limits average power dissipation during fault to prevent thermal runaway. |
| Monotonic start-up with prebias support | Prevents output voltage undershoot or reverse current when powered into existing rail; critical for hot-swap and multi-rail systems. |
| Input transient protection to 50V | Withstands 50V/10ns transients on VIN - meets IEC 61000-4-4 Level 3 surge immunity requirements without external clamping. |
Applications
| PLC Analog I/O Module | Smart Meter Auxiliary Power |
|---|---|
|
Use Scenario: Powering 16-bit SAR ADCs, isolated RS-485 transceivers, and microcontroller peripherals from a 24V field bus. IC Role / Device Role / Timing Role: Primary 3.3V/0.6A point-of-load regulator delivering clean, low-noise supply with constant 1.1MHz switching to minimize conducted EMI coupling into analog sections. Use Value: FPWM mode eliminates frequency dithering, ensuring predictable noise spectrum; 80ns tON_MIN supports 24V→3.3V conversion without foldback at full load. |
Use Scenario: Generating stable 5V rail for metrology SoCs and real-time clocks in Class 0.2 electricity meters operating in outdoor cabinets. IC Role / Device Role / Timing Role: Industrial-grade buck converter providing regulated auxiliary power with –40°C to 150°C operation and 50V transient tolerance on utility-connected inputs. Use Value: ±1.5% reference tolerance and internal soft-start (2.3ms) ensure accurate energy measurement calibration and prevent inrush-induced brownouts during cold starts. |
| Industrial HMI Display Backlight Driver | Factory Automation Sensor Node |
|
Use Scenario: Supplying 12V/0.3A to LED backlight strings in ruggedized touch-panel HMIs exposed to vibration and wide ambient temperature swings. IC Role / Device Role / Timing Role: Compact 0.6A buck converter configured for adjustable 12V output, leveraging FPWM for consistent dimming control and low-output-ripple performance. Use Value: 98% max duty cycle enables dropout operation down to ~12.2V input; thermal shutdown (165°C) protects against enclosure overheating in sealed enclosures. |
Use Scenario: Powering ultra-low-power wireless sensor nodes (sub-GHz RF + Cortex-M0+) from 12V or 24V factory wiring harnesses. IC Role / Device Role / Timing Role: Efficient 3.3V/0.6A regulator supporting intermittent wake-up bursts while maintaining <1µA shutdown current (ISD = 0.8–3µA). Use Value: Precision enable allows deep-sleep control via microcontroller GPIO; PFM/FPWM pin compatibility enables future upgrade to LMR51410YFDBVR for higher current if needed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR51406YDBVR | Same 0.6A/1.1MHz rating but uses PFM mode instead of FPWM; 26.5–40µA quiescent current vs. 420µA in FPWM. | Better light-load efficiency; unsuitable where constant frequency and low output ripple are required (e.g., sensitive analog circuits). | Select LMR51406YDBVR only when optimizing for battery-life extension in always-on sensor nodes with highly variable load. |
| LMR51410YFDBVR | Pin-compatible 1A version with identical 1.1MHz FPWM operation, same package, and extended current capability. | Supports higher-power peripherals (e.g., Ethernet PHYs, dual-band radios); shares same layout and feedback network. | Choose LMR51410YFDBVR when future-proofing for increased load or when marginally exceeding 0.6A peak current in burst-mode operation. |
Compared with LMR51406YDBVR, the LMR51406YFDBVR trades light-load efficiency for predictable EMI and tighter regulation; compared with LMR51410YFDBVR, it offers lower cost and thermal footprint where 0.6A is sufficient, avoiding unnecessary derating.
Availability
LMR51406YFDBVR is available at Aetrix Electronics and suitable for PLC analog I/O modules, smart meter auxiliary power supplies, and industrial HMI display backlight drivers requiring stable component supply, long-term industrial lifecycle support, and traceable sourcing.
Supply support for LMR51406YFDBVR 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 ICs, with decades of industrial-grade reliability validation and functional safety documentation support.
The LMR514xx family targets rugged industrial power conversion, delivering easy-to-use, wide-input synchronous buck regulators with integrated protection and simplified layout - specifically engineered for PLCs, smart meters, and factory automation edge nodes.
FAQ
What is the maximum input voltage the LMR51406YFDBVR can withstand during transients?
The LMR51406YFDBVR supports input transients up to 50V for durations less than 10ns, as specified in its Absolute Maximum Ratings. This transient tolerance enables robust operation in industrial environments with inductive load switching or lightning-induced surges without requiring external TVS diodes in many cases. The device remains functional within its recommended 4V–42V operating range during steady-state conditions.
Does the LMR51406YFDBVR require external compensation components?
No, the LMR51406YFDBVR features fully internal compensation, eliminating the need for external Type-II or Type-III compensation networks. This simplifies design, reduces bill-of-materials count, and improves stability across varying output capacitor ESR values. Only the FB resistor divider, input/output capacitors, and power inductor are required for basic operation.
Can the LMR51406YFDBVR be used with a prebiased output during start-up?
Yes, the LMR51406YFDBVR supports monotonic start-up with prebiased output capability. Its internal soft-start circuit ramps the reference voltage gradually, preventing reverse current flow or output voltage undershoot when enabled into an already-powered rail - a critical feature for hot-swap and multi-rail power sequencing in industrial controllers.
What is the purpose of the CB pin on the LMR51406YFDBVR?
The CB (bootstrap capacitor) pin on the LMR51406YFDBVR connects to a 100nF ceramic capacitor tied to the SW node. It provides the gate drive voltage for the internal high-side N-channel MOSFET during each switching cycle. Proper placement and selection of this capacitor - using X7R/X5R dielectric with ≥16V rating - is essential for reliable high-side FET turn-on and overall converter efficiency.
How does hiccup-mode protection work in the LMR51406YFDBVR?
Hiccup-mode protection in the LMR51406YFDBVR activates after 256 consecutive current-limit cycles triggered by sustained overload or short-circuit conditions. The device shuts down for approximately 150ms (THICCUP), then attempts automatic restart. This cycle repeats until the fault clears, limiting average power dissipation and preventing thermal damage - especially valuable in sealed enclosures without active cooling.
LMR51406YFDBVR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- SOT-23-6
- 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):
- 42V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 28V
- Current - Output:
- 600mA
- Frequency - Switching:
- 1.1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-6
LMR51406YFDBVR FAQ
1.How can I place an order for LMR51406YFDBVR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR51406YFDBVR 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 LMR51406YFDBVR reliable?
The price and inventory of LMR51406YFDBVR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR51406YFDBVR is usually 5 days.
3.What payment methods are accepted for LMR51406YFDBVR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR51406YFDBVR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR51406YFDBVR?
LMR51406YFDBVR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR51406YFDBVR 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 LMR51406YFDBVR?
For technical support, including LMR51406YFDBVR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR51406YFDBVR requirements.
6.How does Aetrix verify that LMR51406YFDBVR is sourced from the original manufacturer or authorized distributors?
All LMR51406YFDBVR 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 LMR51406YFDBVR meets industry standards.
7.What is the process for return or replacement of LMR51406YFDBVR?
All LMR51406YFDBVR units undergo pre-shipment inspection (PSI). If there is an issue with LMR51406YFDBVR, 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 LMR51406YFDBVR part is unused and in its original packaging.
Return procedure for LMR51406YFDBVR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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