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Texas Instruments LMR51406YDBVR
- Part No.:
- LMR51406YDBVR
- Manufacturer:
- Texas Instruments
- Package:
- SOT-23-6
- Datasheet:
-
LMR51406YDBVR.pdf
- Description:
- IC REG BUCK ADJ 600MA SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:2,983
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Product details
Overview
LMR51406YDBVR from Texas Instruments is a synchronous buck DC/DC converter delivering 0.6A output current with 1.1MHz fixed switching frequency, 4V–42V input range, and adjustable output voltage via feedback resistor divider. It integrates high- and low-side MOSFETs, internal compensation, and operates in PFM mode for light-load efficiency in industrial power conditioning applications.
For engineers reviewing the LMR51406YDBVR datasheet, LMR51406YDBVR pinout, LMR51406YDBVR application, or LMR51406YDBVR equivalent, key selection factors include its 1.1MHz PFM operation, 80ns minimum on-time, ±1.5% reference tolerance, thermal shutdown at 165°C, and SOT-23-6 package suitability for space-constrained PLC and smart meter designs.
Technical Context
The LMR51406YDBVR employs fixed-frequency peak-current mode control with internal slope compensation and an integrated 0.8V reference. Its PFM operation reduces switching losses at light loads while maintaining regulation across –40°C to +150°C junction temperature.
It features cycle-by-cycle current limiting, hiccup-mode short-circuit protection triggered at FB < 0.32V, and precision enable with 1.227V turn-on threshold. Frequency foldback extends duty cycle capability below 4V input by reducing switching frequency down to ~200kHz.
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 auxiliary rails in PLC I/O modules and smart meter MCU cores |
| Switching Frequency | 1.1MHz (±13%) - enables compact 1µH–2.2µH inductors and reduces output ripple vs. 400kHz variants |
| Reference Voltage | 0.8V ±1.5% - sets tight output regulation accuracy over temperature and line/load conditions |
| Min On-Time | 80ns - allows high step-down ratios (e.g., 24V→3.3V) without frequency foldback at full load |
| Junction Temp Range | –40°C to +150°C - rated for under-hood, factory-floor, and enclosed industrial environments |
| Quiescent Current | 26.5–40µA (PFM) - enables >90% efficiency at 1mA load in always-on monitoring circuits |
Pinout & Package
SOT-23-6 (DBV) package: 2.90mm × 2.80mm footprint, thermally enhanced with exposed pad (not electrically connected), suitable for reflow assembly and high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CB | Bootstrap capacitor connection | Connects 100nF X7R ceramic to SW; supplies gate drive for integrated high-side MOSFET |
| GND | Power ground | Common return for internal low-side FET, CIN, COUT; requires shortest possible trace to CIN |
| FB | Feedback input | Resistor divider node setting VOUT = 0.8V × (1 + RFBT/RFBB); must not be shorted to GND |
| EN | Precision enable | Active-high logic input (1.227V typical turn-on); supports system UVLO via external resistor divider |
| VIN | Input supply | Connects to 4–42V source and local 4.7µF–10µF input capacitor; powers internal bias LDO |
| SW | Switching node | Drives external power inductor; connects internally to drain of low-side FET and source of high-side FET |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode; improves full-load efficiency by ~5% vs. asynchronous alternatives |
| Internal compensation | Reduces BOM count to only 4 external components (CIN, COUT, L, FB divider) for stable operation |
| Monotonic start-up with prebiased output | Prevents reverse current flow into powered outputs during hot-plug or brownout recovery |
| Hiccup-mode short-circuit protection | Shuts down for 150ms after 256 consecutive current-limit cycles; limits average power dissipation to <100mW |
| Input transient protection to 50V | Withstands 50V/10ns transients per JEDEC JESD22-A114 - no external TVS required for most 24V industrial surges |
Applications
| PLC Digital I/O Power | Smart Meter MCU Rail |
|---|---|
Use Scenario: Powers isolated digital input/output modules in programmable logic controllers operating from 24V DC field bus. IC Role / Device Role / Timing Role: Primary 3.3V/0.6A buck regulator supplying FPGA configuration, isolation drivers, and communication ICs. Use Value: 1.1MHz switching enables use of 1.5µH shielded inductor; PFM mode maintains >85% efficiency at 10mA standby current. | Use Scenario: Generates stable 1.8V core rail for metrology SoC in ANSI C12.20-compliant electricity meters. IC Role / Device Role / Timing Role: Secondary regulated supply derived from 5V intermediate rail; supports low-noise analog front-end sequencing. Use Value: ±1.5% reference tolerance ensures ADC reference stability; 150°C rating accommodates sealed meter enclosure temperatures. |
| Industrial Sensor Node | DC Motor Control Auxiliary Supply |
Use Scenario: Powers wireless sensor nodes with sub-100µA sleep current and 50mA burst transmit loads in factory automation. IC Role / Device Role / Timing Role: Always-on buck converter enabling fast wake-up from deep-sleep states without cold-start delay. Use Value: 26.5µA PFM quiescent current extends battery life; monotonic start-up prevents data corruption during power recovery. | Use Scenario: Supplies 5V logic and gate driver bias for H-bridge motor controllers in HVAC actuators. IC Role / Device Role / Timing Role: Dedicated auxiliary rail decoupled from noisy motor power path; immune to 42V load-dump transients. Use Value: 50V transient rating eliminates need for external clamping; hiccup protection prevents latch-up during stall conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR51406XDBVR | Same 0.6A rating and SOT-23-6 package but 400kHz PFM switching frequency | Better light-load efficiency than LMR51406YDBVR below 10mA; larger inductor required | Select when optimizing for ultra-low standby power over size constraints |
| LMR51410YDBVR | 1A output current, identical 1.1MHz PFM frequency and pinout | Supports higher-power peripherals (e.g., RS-485 transceivers, CAN PHY) without redesign | Select when future-proofing for 1A load growth or sharing layout with 1A variant |
Compared with LMR51406YDBVR, the XDBVR variant trades switching frequency for higher light-load efficiency, while the LMR51410YDBVR offers double the output current in identical footprint-enabling scalable power design without layout change.
Availability
LMR51406YDBVR is available at Aetrix Electronics and suitable for PLC digital I/O modules, smart meter MCU rails, and industrial sensor nodes requiring stable component supply with extended temperature support and transient robustness.
Supply support for LMR51406YDBVR 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 ICs for industrial and automotive markets.
The LMR514xx family targets rugged industrial DC/DC conversion, emphasizing ease-of-use through internal compensation, wide VIN range, and functional safety documentation support for safety-critical systems.
FAQ
What is the maximum input voltage transient the LMR51406YDBVR can withstand?
The LMR51406YDBVR is rated for input transients up to 50V for durations less than 10ns, as specified in its Absolute Maximum Ratings table. This capability allows direct connection to 24V industrial buses without external TVS diodes in most surge environments defined by IEC 61000-4-4 and ISO 16750-2 standards. The device's internal circuitry clamps these events without latch-up or degradation, provided the average input remains within 4V–42V operating range.
Does the LMR51406YDBVR require external compensation components?
No, the LMR51406YDBVR features fully internal compensation, eliminating the need for external Type-II or Type-III compensation networks. This design reduces total BOM count to just four essential external components: input capacitor (CIN), output capacitor (COUT), power inductor (L), and FB resistor divider. Internal compensation ensures stable loop response across all recommended output capacitors-including low-ESR ceramics-and simplifies layout by removing sensitive compensation trace routing.
How does the LMR51406YDBVR handle short-circuit conditions?
The LMR51406YDBVR responds to sustained short-circuits using hiccup-mode protection: after detecting 256 consecutive current-limit cycles (triggered when FB voltage drops below 0.32V), it shuts down for 150ms before attempting restart. This limits average power dissipation to under 100mW during fault, preventing thermal runaway. Cycle-by-cycle current limiting remains active during normal operation, with high-side peak limit at 0.8–1.4A and low-side valley limit at 0.62–0.98A, ensuring robust overload handling without external sensing.
Can the LMR51406YDBVR be used with a prebiased output?
Yes, the LMR51406YDBVR supports monotonic start-up into a prebiased output, meaning it will not force reverse current into an already-powered rail during power-up or recovery from brownout. This behavior is enabled by internal circuitry that monitors FB voltage during soft-start and disables high-side switching until the output reaches regulation. It is critical for systems with multiple power domains or hot-swap capability where downstream circuitry may retain charge when main input is cycled.
What is the purpose of the CB pin on the LMR51406YDBVR?
The CB (bootstrap capacitor) pin on the LMR51406YDBVR provides the gate drive voltage for the integrated high-side N-channel MOSFET. A 100nF X7R ceramic capacitor must be placed between CB and SW pins; during low-side conduction, this capacitor charges from the internal LDO and then supplies boosted voltage to turn on the high-side switch. Proper CB capacitor selection and placement-using short, low-inductance traces-is essential for reliable high-side drive and overall converter efficiency, especially at 1.1MHz switching frequency.
LMR51406YDBVR 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
LMR51406YDBVR FAQ
1.How can I place an order for LMR51406YDBVR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR51406YDBVR 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 LMR51406YDBVR reliable?
The price and inventory of LMR51406YDBVR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR51406YDBVR is usually 5 days.
3.What payment methods are accepted for LMR51406YDBVR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR51406YDBVR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR51406YDBVR?
LMR51406YDBVR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR51406YDBVR 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 LMR51406YDBVR?
For technical support, including LMR51406YDBVR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR51406YDBVR requirements.
6.How does Aetrix verify that LMR51406YDBVR is sourced from the original manufacturer or authorized distributors?
All LMR51406YDBVR 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 LMR51406YDBVR meets industry standards.
7.What is the process for return or replacement of LMR51406YDBVR?
All LMR51406YDBVR units undergo pre-shipment inspection (PSI). If there is an issue with LMR51406YDBVR, 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 LMR51406YDBVR part is unused and in its original packaging.
Return procedure for LMR51406YDBVR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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