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Texas Instruments LMR51420YFDDCR
- Part No.:
- LMR51420YFDDCR
- Manufacturer:
- Texas Instruments
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LMR51420YFDDCR.pdf
- Description:
- IC REG BUCK ADJ 2A SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:1,055
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Product details
Overview
LMR51420YFDDCR from Texas Instruments is a synchronous buck DC-DC converter delivering up to 2-A continuous output current with 4.5-V to 36-V input range, fixed 1.1-MHz switching frequency, and FPWM operation for constant-frequency, low-ripple regulation in industrial power supplies.
For engineers reviewing the LMR51420YFDDCR datasheet, LMR51420YFDDCR pinout, LMR51420YFDDCR application, or LMR51420YFDDCR equivalent, key selection factors include its SOT-23-6 package footprint, ±1.5% reference voltage accuracy, 70-ns minimum on-time, hiccup-mode short-circuit protection, and precision enable with adjustable UVLO.
Technical Context
The LMR51420YFDDCR uses fixed-frequency peak-current mode control with internal compensation, enabling stable regulation across wide input and load ranges without external loop components. It integrates high-side and low-side NMOS FETs with RDSON(HS) = 0.12 Ω and RDSON(LS) = 0.07 Ω at 25°C, supporting efficient 2-A operation.
Its FPWM mode maintains constant 1.1-MHz switching across all loads-ensuring tight output voltage regulation (±1.5% over temperature), low ripple, and predictable EMI behavior-while thermal shutdown (163°C), cycle-by-cycle current limit, and hiccup-mode short-circuit protection ensure robustness in unregulated industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 36 V - supports direct connection to 12/24-V industrial rails and battery-backed systems without pre-regulation. |
| Output Current | 2 A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in compact embedded systems. |
| Switching Frequency | 1.1 MHz (fixed) - enables use of small, low-profile inductors (e.g., 1–2.2 µH) and reduces solution size vs. lower-frequency alternatives. |
| Reference Voltage | 0.6 V ±1.5% - sets output voltage via resistor divider; enables precise 3.3-V, 5-V, or custom outputs with minimal drift over –40°C to 150°C. |
| Min. On-Time | 70 ns - allows high step-down ratios (e.g., 24 V → 3.3 V) at 1.1 MHz without frequency foldback under typical conditions. |
| Junction Temp Range | –40°C to +150°C - rated for under-hood, motor drive, and factory-floor environments without derating. |
| Enable Threshold | VEN(R) = 1.227 V (typ), hysteresis = 0.14 V - supports clean, noise-immune startup and system-level sequencing with external resistor divider. |
Pinout & Package
LMR51420YFDDCR is housed in a thermally enhanced 6-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for high-power density and PCB space-constrained designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND | Power ground | Internal low-side FET source node; must connect directly to system ground and CIN/COUT ground planes with minimal trace length. |
| SW | Switching node | Drain of high-side FET / source of low-side FET; connects to inductor; requires tight layout to minimize EMI and switching losses. |
| VIN | Input supply | Bias and high-side gate driver supply; must be decoupled with ≥10 µF ceramic capacitor placed adjacent to pin. |
| FB | Feedback input | Senses output voltage via resistor divider; high-impedance analog input (leakage <50 nA); avoid routing near noisy nodes. |
| EN | Enable control | Logic-level precision enable; sinking current <200 nA; ties to VIN for self-start or to resistor divider for programmable UVLO. |
| CB | Bootstrap capacitor | Supplies gate drive for high-side FET; requires 100-nF X7R/X5R ceramic capacitor between CB and SW pins. |
Key Features
| Feature | Design Value |
|---|---|
| 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 design time while ensuring stability with common output capacitors. |
| FPWM operation mode | Maintains fixed 1.1-MHz switching across 0–2 A load range-enabling predictable EMI filtering and consistent transient response. |
| Hiccup-mode short-circuit protection | Shuts down for 135 ms after fault detection, then retries-prevents thermal runaway during sustained overload without requiring external circuitry. |
| Start-up with prebiased output | Allows safe turn-on when VOUT is already biased (e.g., by another rail); prevents reverse current flow into the output capacitor. |
Applications
| Industrial Motor Drives | Building Automation Sensors |
|---|---|
Use Scenario: Powering gate drivers and position feedback ICs in BLDC motor inverters operating from 24-V bus with variable load transients. IC Role / Device Role / Timing Role: Primary 5-V/3.3-V point-of-load regulator supplying isolated gate drivers and Hall-effect sensor interfaces. Use Value: 1.1-MHz FPWM ensures stable regulation during rapid current spikes; 150°C junction rating supports placement near heat-generating IGBT modules. | Use Scenario: Providing regulated 3.3-V supply to wireless sensor nodes (Zigbee, BLE) mounted in HVAC ducts or lighting fixtures. IC Role / Device Role / Timing Role: Compact, high-efficiency buck converter converting 12–30-V building power to ultra-low-noise 3.3-V for RF and ADC subsystems. Use Value: 70-ns min on-time enables 30-V → 3.3-V conversion at 1.1 MHz; PFM/FPWM option allows firmware-selectable efficiency vs. EMI trade-off. |
| Appliance Control Boards | General-Purpose Wide-VIN Supplies |
Use Scenario: Powering MCU, display, and touch controller on washing machine main board fed from rectified AC line (12–32-V DC). IC Role / Device Role / Timing Role: Main system regulator delivering 3.3-V/2-A with start-up under prebiased output condition during power cycling. Use Value: Prebias start-up prevents output voltage collapse during brownout recovery; ±1.5% reference ensures accurate ADC reference and timing clock generation. | Use Scenario: Replacing linear regulators in legacy industrial equipment where input voltage varies widely (e.g., 12–28-V vehicle or solar-powered systems). IC Role / Device Role / Timing Role: Drop-in synchronous buck replacement offering >85% efficiency at 2 A, eliminating heatsink requirements of 78xx linear regulators. Use Value: SOT-23-6 footprint matches many through-hole TO-220 layouts via adapter; 98% max duty cycle supports operation down to 4.5-V input with minimal dropout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR51420YDDCR | Same 1.1-MHz frequency but PFM mode instead of FPWM; 40 µA quiescent current vs. 65 µA in FPWM variant. | Better light-load efficiency; higher output ripple and variable frequency under light load. | Select YDDCR for battery-powered or always-on sensor nodes prioritizing standby power; choose YFDDCR for noise-sensitive or EMI-regulated systems requiring fixed frequency. |
| TPS54202DRCT | Pin-to-pin compatible; 4.5–28-V input, 2-A, 500-kHz/1.1-MHz selectable frequency; no hiccup-mode short-circuit protection. | Lacks hiccup-mode fault recovery; requires external soft-start capacitor; slightly wider input range than LMR51420YFDDCR's 36-V max. | Choose TPS54202DRCT only if existing layout uses its footprint and hiccup protection is not required; otherwise, LMR51420YFDDCR offers superior fault resilience and integrated soft-start. |
Compared with LMR51420YDDCR, the LMR51420YFDDCR trades ~25 µA higher quiescent current for fixed-frequency operation and tighter ripple control-critical for RF and precision analog circuits. Against TPS54202DRCT, it adds hiccup-mode protection and eliminates external soft-start, reducing component count and improving reliability in harsh environments.
Availability
LMR51420YFDDCR is available at Aetrix Electronics and suitable for industrial motor drives, building automation sensors, appliance control boards, and general-purpose wide-VIN power supplies requiring stable component supply and long-term manufacturability.
Supply support for LMR51420YFDDCR 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 designing analog and embedded processing chips for industrial, automotive, and communications markets, with over 90 years of innovation in power management ICs.
The LMR51420 family targets rugged, space-constrained industrial power conversion-delivering SIMPLE SWITCHER® ease-of-use, wide-VIN capability, and integrated protection in ultra-small packages for next-generation factory automation and energy infrastructure.
FAQ
What is the maximum input voltage rating for the LMR51420YFDDCR?
The LMR51420YFDDCR has an absolute maximum input voltage rating of 38 V, with recommended operating range from 4.5 V to 36 V. Exceeding 36 V continuously may trigger undervoltage lockout or reduce reliability; operation at 36 V is fully specified for 2-A output across the full temperature range.
Does the LMR51420YFDDCR require external compensation components?
No, the LMR51420YFDDCR features fully internal compensation, eliminating the need for external Type-II or Type-III compensation networks. This simplifies design, reduces BOM count, and ensures stable operation with standard ceramic output capacitors-verified across 10–100 µF ranges in TI's reference designs.
Can the LMR51420YFDDCR start up when the output is already biased to a voltage?
Yes, the LMR51420YFDDCR supports start-up with prebiased output-a critical feature for systems recovering from brownouts or sharing outputs with backup supplies. During start-up, the device actively controls the high-side FET to prevent reverse current flow into the output capacitor, avoiding potential damage or latch-up.
What is the purpose of the CB pin on the LMR51420YFDDCR?
The CB (bootstrap capacitor) pin on the LMR51420YFDDCR provides gate drive voltage for the integrated high-side NMOS FET. A 100-nF ceramic capacitor must be placed between CB and SW pins; it is charged during low-side conduction and enables full enhancement of the high-side switch, ensuring efficient 100% duty-cycle capability and low RDSON utilization.
How does hiccup-mode short-circuit protection work in the LMR51420YFDDCR?
When the LMR51420YFDDCR detects a sustained short circuit, it enters hiccup mode: it shuts down for 135 ms, then attempts restart. If the fault persists, the cycle repeats. This limits average power dissipation, prevents thermal runaway, and avoids catastrophic failure-unlike latch-off protection, it enables autonomous recovery once the fault clears without requiring system-level reset.
LMR51420YFDDCR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- SOT-23-6 Thin, TSOT-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):
- 4.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 34.2V
- Current - Output:
- 2A
- 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-THIN
LMR51420YFDDCR FAQ
1.How can I place an order for LMR51420YFDDCR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR51420YFDDCR 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 LMR51420YFDDCR reliable?
The price and inventory of LMR51420YFDDCR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR51420YFDDCR is usually 5 days.
3.What payment methods are accepted for LMR51420YFDDCR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR51420YFDDCR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR51420YFDDCR?
LMR51420YFDDCR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR51420YFDDCR 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 LMR51420YFDDCR?
For technical support, including LMR51420YFDDCR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR51420YFDDCR requirements.
6.How does Aetrix verify that LMR51420YFDDCR is sourced from the original manufacturer or authorized distributors?
All LMR51420YFDDCR 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 LMR51420YFDDCR meets industry standards.
7.What is the process for return or replacement of LMR51420YFDDCR?
All LMR51420YFDDCR units undergo pre-shipment inspection (PSI). If there is an issue with LMR51420YFDDCR, 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 LMR51420YFDDCR part is unused and in its original packaging.
Return procedure for LMR51420YFDDCR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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