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Texas Instruments LMR66430MB3RXBR
- Part No.:
- LMR66430MB3RXBR
- Manufacturer:
- Texas Instruments
- Package:
- 14-PowerTFQFN
- Datasheet:
-
LMR66430MB3RXBR.pdf
- Description:
- IC REG BUCK ADJ/1V 3A 14VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,989
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Product details
Overview
LMR66430MB3RXBR from Texas Instruments is a 36-V, 3-A synchronous step-down DC/DC converter in a 2.6-mm × 2.6-mm enhanced HotRod™ QFN package, featuring fixed 3.3-V output, 1-MHz switching frequency, MODE/SYNC pin for PFM/FPWM selection and external clock synchronization, and input transient protection up to 42 V. It delivers >85% efficiency at 1 mA and supports industrial applications requiring ultra-low quiescent current (1.5 µA) and wide junction temperature range (–40°C to +150°C).
For engineers reviewing the LMR66430MB3RXBR datasheet, LMR66430MB3RXBR pinout, LMR66430MB3RXBR application, or LMR66430MB3RXBR equivalent, key selection considerations include its fixed 3.3-V output with ±0.3% accuracy over temperature, dual-random spread spectrum for EMI reduction, factory-set 1-MHz FPWM/Auto mode control via MODE/SYNC, thermal shutdown at 168°C, and PG open-drain power-good flag with 2.5-ms activation delay.
Technical Context
The LMR66430MB3RXBR uses peak-current-mode control with internal compensation and implements frequency foldback in Auto mode to maintain regulation at light loads while achieving 1.5 µA no-load input current. Its MODE/SYNC pin enables seamless transition between PFM (diode emulation enabled) and FPWM (diode emulation disabled) operation, and supports in-phase PLL-based synchronization to external clocks from 0.2 MHz to 2.5 MHz.
Designed for high-reliability industrial systems, it integrates NC pins between critical high-voltage nodes (VIN, SW, BOOT), features wettable-flank QFN packaging for optical solder inspection, and includes robust protection: thermal shutdown with 20°C hysteresis, input UVLO (3.35 V rising), output overvoltage/undervoltage detection on PG, and 42-V input transient tolerance - all within a 14-pin RXB package optimized for minimal EMI and compact layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A continuous DC output - supports high-power industrial rails without external current boosting. |
| Input Voltage Range | 3.0 V to 36 V after start-up, with 42-V transient tolerance - eliminates need for upstream TVS in harsh environments. |
| Output Voltage | Fixed 3.3 V ±0.3% over –40°C to +150°C - ensures stable logic supply for microcontrollers and FPGAs. |
| Switching Frequency | Factory-set 1 MHz (±10%) - balances efficiency, size, and EMI for compact PCB layouts. |
| Quiescent Current | 1.5 µA at 13.5 V VIN, no load, Auto mode - enables always-on functionality in battery-backed systems. |
| Thermal Shutdown | 168°C trip with 20°C hysteresis - protects against sustained overload or poor heatsinking in sealed enclosures. |
| Power-Good Flag | Open-drain PG with 2.5-ms activation delay and 91–94.2% UV threshold - replaces discrete reset supervisors in PLCs and PACs. |
Pinout & Package
LMR66430MB3RXBR is housed in a 14-pin enhanced HotRod™ VQFN-FCRLF (RXB) package measuring 2.6 mm × 2.6 mm with wettable flanks and an exposed thermal pad (GND/DAP) that must be soldered to PCB ground for thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN | Enable / UVLO input | Logic-controlled startup with precision 1.23-V rising threshold and 0.35-V hysteresis - allows direct connection to VIN or microcontroller GPIO. |
| VIN | Main input supply | Accepts 3.0–36 V with 42-V transient rating - requires local ceramic bypass capacitor to PGND for stability. |
| SW | Switch node | Connects to power inductor; high dv/dt node - minimized ringing via bond-wire-free HotRod packaging. |
| BOOT | Bootstrap supply | Requires 0.1-µF/16-V capacitor to SW - enables high-side MOSFET gate drive above VIN. |
| VOUT/FB | Output voltage sense / feedback | Fixed 3.3-V output; pin tied internally to reference - no external resistor divider needed. |
| MODE/SYNC | Mode control / clock sync | Configures PFM/FPWM operation or accepts external 0.2–2.5 MHz sync clock - enables deterministic timing in multi-rail systems. |
| PG | Power-good flag | Open-drain output asserting high when VOUT is within ±1.2% of 3.3 V - provides system-level power sequencing signal. |
| GND/DAP | Power ground / thermal pad | Exposed copper pad must be soldered to solid GND plane - achieves 26.2°C/W junction-to-board thermal resistance. |
Key Features
| Feature | Design Value |
|---|---|
| Functional Safety-Capable | Documentation available for ISO 26262/IEC 61508 system-level safety analysis - supports SIL2/ASIL B designs. |
| Dual Random Spread Spectrum (DRSS) | Reduces peak EMI emissions by spreading switching frequency across ±10% bandwidth - lowers filter component count and cost. |
| Enhanced HotRod™ QFN | Bond-wire-free construction with wettable flanks - enables automated optical inspection and improves solder joint reliability in thermal cycling. |
| Internal Compensation | No external compensation components required - simplifies design, reduces BOM count, and accelerates time-to-market. |
| NC Pin Isolation | No-connect pins placed between VIN, SW, and BOOT - mitigates creepage/corona risks and improves field failure rate (FMEA-optimized). |
Applications
| PLC Power Supply | Medical Sensor Module |
|---|---|
Use Scenario: Compact 24-V input to 3.3-V rail powering ARM Cortex-M7 MCU, isolated CAN transceiver, and analog front-end in modular PLC I/O cards. IC Role / Device Role: Primary point-of-load regulator delivering clean, regulated 3.3 V with fast transient response and low noise. Use Value: 1.5 µA quiescent current extends backup battery life during mains loss; 150°C junction rating enables operation in unventilated DIN-rail enclosures. | Use Scenario: Battery-powered wearable vital sign monitor requiring ultra-low standby power and EMI-compliant 3.3-V supply for ADC, Bluetooth SoC, and OLED display. IC Role / Device Role: Always-on buck converter enabling wake-on-event architecture with sub-µA sleep current. Use Value: DRSS and HotRod packaging meet CISPR-11 Class B radiated emissions limits without shielding; PG flag triggers MCU wake-up on valid rail. |
| Aerospace Avionics | Test Equipment Power |
Use Scenario: Ruggedized flight data recorder using 28-V aircraft bus to generate 3.3-V logic rail under extreme temperature and vibration. IC Role / Device Role: High-reliability DC/DC converter with built-in fault reporting and thermal margin. Use Value: NC pin isolation and 168°C thermal shutdown prevent single-point failures; PG flag signals health status to flight control processor. | Use Scenario: Benchtop oscilloscope mainboard requiring low-noise, tightly regulated 3.3-V supply for high-speed ADC and FPGA fabric. IC Role / Device Role: Precision power rail generator with minimal output ripple and fast load-step response. Use Value: Fixed 3.3-V accuracy (±0.3%) ensures ADC reference stability; 1-MHz FPWM mode eliminates audible switching noise in lab environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR66430R5RXBR | Fixed 5-V output; RT pin for adjustable frequency (200 kHz–2.2 MHz); no MODE/SYNC functionality | Suitable for 5-V logic systems where external sync or PFM/FPWM selection is unnecessary | Select when 5-V rail is required and frequency flexibility outweighs sync capability |
| TPS54360BDDAR | 3.5-A output; 3.5–60-V input; adjustable frequency (100 kHz–2.5 MHz); no spread spectrum or PG flag | Higher input voltage range but lacks EMI optimization and integrated power-good signaling | Choose for wider VIN range where DRSS and PG are not critical |
Compared with LMR66430R5RXBR and TPS54360BDDAR, the LMR66430MB3RXBR uniquely combines fixed 3.3-V output, factory-set 1-MHz MODE/SYNC control, dual-random spread spectrum, and open-drain PG in a 2.6-mm² package - making it optimal for space-constrained, EMI-sensitive, and safety-aware industrial 3.3-V systems.
Availability
LMR66430MB3RXBR is available at Aetrix Electronics and suitable for factory automation, medical sensor modules, and aerospace avionics requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LMR66430MB3RXBR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The LMR664x0 product line was designed specifically for high-reliability, low-quiescent-current industrial power conversion - targeting PLCs, PACs, test equipment, and medical devices operating across –40°C to +150°C with stringent EMI and functional safety requirements.
FAQ
What is the output voltage configuration of the LMR66430MB3RXBR?
The LMR66430MB3RXBR features a factory-configured fixed 3.3-V output. Unlike adjustable variants, it does not require external feedback resistors - the VOUT/FB pin is internally connected to the 3.3-V reference. Output voltage accuracy is ±0.3% over –40°C to +150°C, ensuring stable logic supply for microcontrollers and sensors in demanding environments. This fixed configuration simplifies design and improves long-term reliability compared to resistor-based setups.
How does the MODE/SYNC pin function on the LMR66430MB3RXBR?
On the LMR66430MB3RXBR, the MODE/SYNC pin enables user-selectable PFM/FPWM operation or external clock synchronization. Applying a logic-high voltage (>1.6 V) selects FPWM mode (fixed 1-MHz switching, diode emulation disabled); logic-low (<1 V) selects Auto mode (PFM at light loads, diode emulation enabled). A valid external clock (0.2–2.5 MHz) forces SYNC mode, locking the internal oscillator phase to the input signal. This pin eliminates need for external mode control circuitry in multi-rail systems.
What thermal performance can be expected from the LMR66430MB3RXBR in a typical PCB layout?
In a standard 4-layer JEDEC board, the LMR66430MB3RXBR achieves a junction-to-board thermal resistance (RθJB) of 26.2°C/W. With proper thermal pad soldering to a solid GND plane, it sustains 3-A continuous output at +150°C junction temperature. Thermal shutdown activates at 168°C with 20°C hysteresis, allowing safe recovery without manual reset. The device's 2.6-mm × 2.6-mm HotRod package minimizes thermal impedance versus traditional QFNs, supporting compact, fanless industrial designs.
Does the LMR66430MB3RXBR support input voltages below 3.6 V?
Yes - the LMR66430MB3RXBR supports an input voltage range of 3.0 V to 36 V after start-up, with a falling UVLO threshold of 2.7 V. While start-up requires ≥3.35 V (rising threshold), once operational, it maintains regulation down to 3.0 V. This enables compatibility with partially discharged 3.7-V Li-ion batteries or brownout conditions in 3.3-V systems. Input transient tolerance remains at 42 V regardless of operating voltage, protecting against load-dump events in industrial power buses.
What protection features are integrated into the LMR66430MB3RXBR?
The LMR66430MB3RXBR integrates thermal shutdown (168°C trip, 20°C hysteresis), input overvoltage lockout (42-V absolute max), output overvoltage/undervoltage detection (via PG flag), valley current limiting, and zero-cross current limiting in Auto mode. It also includes high-side MOSFET overcurrent protection (4.4-A typical peak limit) and low-side valley current limiting (3.5-A typical). These protections operate autonomously without external components, ensuring robust operation in unattended industrial deployments where LMR66430MB3RXBR serves as the primary power source.
LMR66430MB3RXBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-PowerTFQFN
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Fixed)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- -
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 1V
- Voltage - Output (Max):
- 3.3V
- Current - Output:
- 3A
- Frequency - Switching:
- -
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 14-VQFN (2.6x2.6)
LMR66430MB3RXBR FAQ
1.How can I place an order for LMR66430MB3RXBR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR66430MB3RXBR 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 LMR66430MB3RXBR reliable?
The price and inventory of LMR66430MB3RXBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR66430MB3RXBR is usually 5 days.
3.What payment methods are accepted for LMR66430MB3RXBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR66430MB3RXBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR66430MB3RXBR?
LMR66430MB3RXBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR66430MB3RXBR 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 LMR66430MB3RXBR?
For technical support, including LMR66430MB3RXBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR66430MB3RXBR requirements.
6.How does Aetrix verify that LMR66430MB3RXBR is sourced from the original manufacturer or authorized distributors?
All LMR66430MB3RXBR 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 LMR66430MB3RXBR meets industry standards.
7.What is the process for return or replacement of LMR66430MB3RXBR?
All LMR66430MB3RXBR units undergo pre-shipment inspection (PSI). If there is an issue with LMR66430MB3RXBR, 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 LMR66430MB3RXBR part is unused and in its original packaging.
Return procedure for LMR66430MB3RXBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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