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Texas Instruments LMR66430R5RXBR
- Part No.:
- LMR66430R5RXBR
- Manufacturer:
- Texas Instruments
- Package:
- 14-PowerTFQFN
- Datasheet:
-
LMR66430R5RXBR.pdf
- Description:
- IC REG BUCK ADJ/1V 3A 14VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,930
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Product details
Overview
LMR66430R5RXBR 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 5-V fixed output, adjustable switching frequency (200 kHz–2.2 MHz), input transient protection up to 42 V, and 1.5 µA quiescent current at no load. It serves as the primary power stage in industrial PLCs and test equipment requiring high reliability under wide temperature (–40°C to +150°C) and harsh voltage transients.
For engineers reviewing the LMR66430R5RXBR datasheet, LMR66430R5RXBR pinout, LMR66430R5RXBR application, or LMR66430R5RXBR equivalent, key selection considerations include its 3-A continuous output capability, dual-random spread spectrum for EMI reduction, NC-pin isolation between high-voltage nodes, auto-mode light-load efficiency, and compatibility with minimal external components including internal compensation.
Technical Context
The LMR66430R5RXBR employs peak-current-mode control with frequency foldback in auto mode, enabling seamless PWM-to-PFM transition and maintaining regulation down to 1.5 µA input current. Its architecture integrates internal loop compensation, dual-random spread spectrum (DRSS), and optimized pinout-including NC pins between VIN and SW-to minimize EMI and improve FMEA robustness.
It supports fixed 5-V output with ±1% accuracy over –40°C to +150°C, features an open-drain power-good (PG) flag with 2.5-ms activation delay and 40-µs deglitching, and uses an enhanced HotRod QFN package with wettable flanks for reliable solder joint inspection and thermal performance (RθJA = 66.1°C/W).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A continuous - supports full-load operation in compact industrial power rails without external current sensing. |
| Input Voltage Range | 2.7 V (falling) to 36 V - enables direct connection to 24-V industrial buses with 42-V transient tolerance. |
| Output Voltage | Fixed 5 V ±1% - eliminates need for external feedback resistors in standard logic supply applications. |
| Quiescent Current | 1.5 µA at 13.5 VIN, no load - sustains ultra-low standby power for always-on factory automation systems. |
| Switching Frequency | Adjustable 200 kHz–2.2 MHz via RT resistor - allows noise-sensitive band avoidance and layout optimization. |
| Thermal Shutdown | 158°C trip, 20°C hysteresis - ensures safe operation in sealed enclosures with limited airflow. |
| Package | RXB (VQFN-14, 2.6 mm × 2.6 mm) with wettable flanks - enables automated optical inspection and 26.2°C/W board-level thermal resistance. |
Pinout & Package
The LMR66430R5RXBR is housed in a 14-pin enhanced HotRod™ VQFN (RXB) package measuring 2.6 mm × 2.6 mm, with exposed thermal pad (GND/DAP) requiring solder connection to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 EN/UVLO | Enable & input undervoltage lockout | Logic-controlled startup; connects directly to VIN for simple enable; precision threshold (1.23 V) enables accurate system sequencing. |
| 3 VIN | Main input power supply | Accepts 2.7–36 V; withstands 42-V transients; requires local ceramic bypass to PGND for stability. |
| 6 PGND | Power ground return | Low-inductance path for high di/dt switch currents; must be routed with short, wide traces to CIN. |
| 7 SW | Switch node | Connects to power inductor; minimized ringing due to bond-wire-free HotRod packaging and DRSS. |
| 8 BOOT | Bootstrap supply for high-side driver | Requires 0.1-µF/16-V capacitor to SW; enables efficient 100% duty cycle capability during dropout. |
| 10 VCC | Internal LDO output | 3.3-V regulated supply for control circuitry; can power external logic or PG pull-up; decoupled with 1-µF capacitor. |
| 11 VOUT/FB | Output voltage sense / feedback | Configured as fixed 5-V output; no external resistors needed; FB function available if adjusted output is required. |
| 13 RT | Frequency adjust | Resistor-to-GND sets switching frequency from 200 kHz to 2.2 MHz; enables EMI tuning without changing layout. |
| 14 PG | Power-good flag | Open-drain output with 2.5-ms delay and 40-µs deglitching; signals valid regulation to host controller or FPGA. |
| 2,4,5,9,12 NC | No-connect | Isolate critical high-voltage pins (VIN, SW, PG); reduce risk of creepage failure and improve pin-level FMEA. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-random spread spectrum (DRSS) | Reduces peak EMI emissions by spreading switching frequency energy across 200-kHz bandwidth-eliminates need for common-mode chokes in many industrial layouts. |
| Enhanced HotRod QFN with wettable flanks | Enables automated optical inspection of solder joints and achieves 26.2°C/W board-level thermal resistance-critical for convection-cooled industrial modules. |
| Auto-mode light-load efficiency | Maintains >85% efficiency at 1 mA while drawing only 1.5 µA quiescent current-enables always-on operation in battery-backed or energy-harvested sensors. |
| Internal loop compensation | Removes requirement for external compensation network-reduces BOM count and design iteration time for 5-V fixed-output configurations. |
| NC-pin isolation between high-voltage nodes | Provides physical separation between VIN, SW, and PG pins-improves field reliability and meets IEC 61000-4-5 surge immunity requirements in PLC backplanes. |
Applications
| Programmable Logic Controller (PLC) Power Rail | Industrial Test Instrumentation |
|---|---|
|
Use Scenario: Powers FPGA, ADC, and isolated I/O in DIN-rail mounted PLCs operating continuously in ambient temperatures up to +70°C. IC Role / Device Role / Timing Role: Primary 5-V buck regulator delivering 3 A with tight output accuracy (±1%) and low ripple for sensitive analog front-ends. Use Value: Input transient protection to 42 V prevents shutdown during 24-V bus faults; 150°C junction rating ensures long-term reliability in sealed enclosures. |
Use Scenario: Supplies 5-V logic and analog circuitry in portable multimeters and automated test equipment with stringent EMI limits. IC Role / Device Role / Timing Role: Fixed-output DC/DC converter with DRSS and optimized HotRod layout minimizing conducted emissions below CISPR 11 Class B limits. Use Value: Adjustable frequency (via RT) avoids interference with internal 1-MHz sampling clocks; PG flag synchronizes firmware initialization sequence. |
| Medical Diagnostic Equipment | Aerospace Data Acquisition Unit |
|
Use Scenario: Provides isolated 5-V supply for patient-connected signal conditioning circuits in ultrasound and ECG devices. IC Role / Device Role / Timing Role: Low-noise, low-quiescent-current regulator supporting battery backup and fast wake-up from standby. Use Value: 1.5 µA shutdown current extends battery life; –40°C to +150°C rating supports sterilization cycles and wide environmental operation. |
Use Scenario: Powers radiation-tolerant microcontrollers and ADCs in satellite telemetry modules with strict size and thermal constraints. IC Role / Device Role / Timing Role: Compact 2.6-mm × 2.6-mm buck converter delivering 3 A with minimal external components and high thermal efficiency. Use Value: Wettable flanks enable X-ray inspection of solder joints; NC-pin spacing improves HV reliability in low-pressure 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 |
|---|---|---|---|
| LMR66430MB3RXBR | 3.3-V fixed output; MODE/SYNC pin supports external clock sync and FPWM/auto mode selection | Preferred where system-level clock synchronization or precise PFM/FPWM control is required | Select when 3.3-V rail is needed and multi-regulator phase alignment matters more than 5-V compatibility |
| TPS54360BDDAR | 3.5-A output; 3.5–60-V input; no integrated DRSS; larger SOIC-8 package (4.9 mm × 6.0 mm) | Suitable for higher-input-voltage industrial systems but lacks EMI-optimized HotRod packaging | Choose when input exceeds 36 V or when legacy SOIC footprint compatibility is mandatory |
Compared with LMR66430MB3RXBR, the LMR66430R5RXBR offers fixed 5-V output and RT-based frequency tuning instead of sync capability-ideal for cost-sensitive, space-constrained 5-V rails. Against TPS54360BDDAR, it delivers superior EMI performance and 45% smaller footprint despite lower max input voltage, making it optimal for modern compact industrial designs.
Availability
LMR66430R5RXBR is available at Aetrix Electronics and suitable for factory automation, test instrumentation, and medical diagnostics requiring stable component supply, long-lifecycle assurance, and consistent parametric performance across production batches.
Supply support for LMR66430R5RXBR 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 deep expertise in industrial-grade power conversion and functional safety solutions.
The LMR664x0 product line was designed specifically for rugged industrial applications-including PLCs, DCS, and PACs-where wide input range, high temperature operation, low EMI, and long-term supply stability are non-negotiable.
FAQ
What is the maximum input voltage the LMR66430R5RXBR can withstand without damage?
The LMR66430R5RXBR has an absolute maximum input voltage rating of 42 V, verified per TI's SNVSCJ3 datasheet Section 6.1. This transient rating allows safe operation during 24-V industrial bus faults and load-dump events. Continuous operation is specified from 3.0 V to 36 V after start-up, with 3.6 V minimum for initial start-up. The 42-V limit applies only to short-duration transients-not sustained operation.
Does the LMR66430R5RXBR require external compensation components?
No, the LMR66430R5RXBR features internal loop compensation optimized for its 5-V fixed-output configuration. As confirmed in Section 7.1 and Table 4-1 of the datasheet, no external compensation network is needed-reducing BOM count and simplifying layout. External compensation is only required if using the adjustable output variant or deviating from recommended inductor/capacitor values.
How does the LMR66430R5RXBR achieve low EMI performance?
The LMR66430R5RXBR achieves low EMI through three integrated features: dual-random spread spectrum (DRSS) dithering, an enhanced HotRod QFN package eliminating bond wires to suppress switch-node ringing, and an optimized pinout with NC pins isolating high-dV/dt nodes (VIN, SW, PG). These are validated in Figure 6-12 and Section 7.3.5 of the SNVSCJ3 datasheet, enabling compliance with CISPR 11 Class B without added filtering.
What is the purpose of the NC pins on the LMR66430R5RXBR package?
The NC pins (pins 2, 4, 5, 9, and 12) on the LMR66430R5RXBR provide physical isolation between high-voltage terminals (VIN, SW, PG) to improve pin-level FMEA and reduce risk of surface creepage failure. As stated in Section 1 and Table 5-1, this design enhances reliability in high-humidity or contaminated industrial environments and supports IEC 61000-4-5 surge immunity requirements.
Can the LMR66430R5RXBR operate with zero load current?
Yes, the LMR66430R5RXBR operates down to zero load in auto mode, drawing only 1.5 µA typical quiescent current at 13.5 VIN (Section 6.6). Its frequency foldback and diode emulation prevent reverse inductor current, maintaining regulation and stability even with no output load-making it ideal for always-on industrial subsystems and battery-backed applications.
LMR66430R5RXBR 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):
- 5V
- 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)
LMR66430R5RXBR FAQ
1.How can I place an order for LMR66430R5RXBR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR66430R5RXBR 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 LMR66430R5RXBR reliable?
The price and inventory of LMR66430R5RXBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR66430R5RXBR is usually 5 days.
3.What payment methods are accepted for LMR66430R5RXBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR66430R5RXBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR66430R5RXBR?
LMR66430R5RXBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR66430R5RXBR 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 LMR66430R5RXBR?
For technical support, including LMR66430R5RXBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR66430R5RXBR requirements.
6.How does Aetrix verify that LMR66430R5RXBR is sourced from the original manufacturer or authorized distributors?
All LMR66430R5RXBR 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 LMR66430R5RXBR meets industry standards.
7.What is the process for return or replacement of LMR66430R5RXBR?
All LMR66430R5RXBR units undergo pre-shipment inspection (PSI). If there is an issue with LMR66430R5RXBR, 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 LMR66430R5RXBR part is unused and in its original packaging.
Return procedure for LMR66430R5RXBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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