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Texas Instruments LMQ66430R5RXBR
- Part No.:
- LMQ66430R5RXBR
- Manufacturer:
- Texas Instruments
- Package:
- 14-PowerTFQFN
- Datasheet:
-
LMQ66430R5RXBR.pdf
- Description:
- IC REG BUCK ADJ/1V 3A 14VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,023
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Product details
Overview
LMQ66430R5RXBR from Texas Instruments is a 36V, 3A synchronous step-down DC/DC converter with integrated VIN bypass and CBOOT capacitors in a 2.6mm × 2.6mm enhanced HotRod™ QFN package. It delivers fixed 5V output or adjustable output up to 95% of VIN, supports 200kHz–2.2MHz switching frequency via RT pin, operates from –40°C to +150°C junction temperature, and achieves >85% efficiency at 1mA for ultra-low-power industrial applications.
For engineers reviewing the LMQ66430R5RXBR datasheet, LMQ66430R5RXBR pinout, LMQ66430R5RXBR application, or LMQ66430R5RXBR equivalent, key selection considerations include its integrated capacitors reducing EMI filter count, dual-random spread spectrum (DRSS) for peak emission suppression, ZEN 2 switcher architecture, thermal robustness for PLC/DCS environments, and auto-mode light-load efficiency down to 1.5µA quiescent current.
Technical Context
The LMQ66430R5RXBR uses peak-current-mode control with frequency foldback in auto mode, enabling seamless PWM-to-PFM transition and maintaining regulation under wide input transients up to 42V. Its internal compensation, integrated 22nF bypass capacitors (series-connected between VIN and PGND), and 0.1µF internal CBOOT eliminate external high-frequency ceramic capacitors.
ZEN 2 switcher features include optimized pinout with NC pins isolating critical HV nodes (e.g., VIN, SW, BOOT), wettable-flank 14-pin VQFN-FCRLF package minimizing switch-node ringing, and DRSS dithering synchronized to oscillator clock to reduce conducted and radiated emissions without external shielding or common-mode chokes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A continuous DC output - supports full-load operation in space-constrained industrial modules without external current boosting. |
| Input Voltage Range | 2.7 V (falling threshold) to 36 V after start-up - accommodates brownout recovery and 24V rail transients in factory automation systems. |
| Output Voltage | Fixed 5 V or adjustable 1 V–18 V - enables direct replacement of legacy 5V LDOs while supporting custom voltage rails in medical instrumentation. |
| Switching Frequency | 200 kHz–2.2 MHz via RT pin - allows noise-sensitive placement near ADCs or RF sections by avoiding AM/FM bands. |
| Quiescent Current | 1.5 µA at 13.5 VIN, no load, auto mode - extends battery life in always-on aerospace monitoring nodes. |
| Thermal Range | –40°C to +150°C junction - certified for under-hood automotive auxiliary supplies and high-temp industrial enclosures. |
| EMI Reduction | Dual-random spread spectrum + enhanced HotRod™ package - eliminates need for external EMI filters in Class B compliance designs. |
Pinout & Package
LMQ66430R5RXBR uses the RXB (VQFN-FCRLF, 14-pin) package: 2.6mm × 2.6mm body with wettable flanks and exposed thermal pad (GND/DAP) requiring PCB solder connection for thermal dissipation and EMI grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 EN | Enable / UVLO input | High-voltage tolerant (up to 42V); precision enable threshold (1.23V typ) enables reliable remote power sequencing in multi-rail systems. |
| 3 VIN | Main input supply | Internally connects to two 22nF series bypass capacitors; requires external bulk capacitor but no high-frequency ceramic needed. |
| 6 PGND | Power ground return | Low-inductance path for high di/dt currents; must be connected to system ground with short, wide traces adjacent to SW. |
| 7 SW | Switch node | Drives external inductor; low parasitic inductance due to HotRod™ flip-chip construction minimizes voltage overshoot. |
| 8 BOOT | Bootstrap supply | Internally connects 0.1µF capacitor to SW; eliminates external bootstrap capacitor and routing loop. |
| 10 VCC | Internal LDO output | 3.3V ±3% regulated supply for control logic; can power PG pull-up or external logic without loading main output. |
| 11 VOUT/FB | Output sense / feedback | Supports fixed 5V or adjustable configuration; FB input leakage <10nA ensures stable regulation with high-value resistors. |
| 13 RT | Frequency adjust | Resistor-to-GND sets FSW from 200kHz–2.2MHz; enables precise EMI band avoidance in dense PCB layouts. |
| 14 PG | Open-drain power-good | Active-low flag with 40µs deglitch and 2.5ms activation delay; replaces external reset supervisor in microcontroller-based PACs. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated VIN bypass & CBOOT capacitors | Eliminates two external 0.1µF ceramics, reducing component count, board area, and high-frequency EMI source points. |
| Dual-random spread spectrum (DRSS) | Reduces peak radiated emissions by >10dB across 30–1000MHz, enabling Class B compliance without metal shielding. |
| Enhanced HotRod™ QFN with wettable flanks | Enables automated optical inspection (AOI) and improves solder joint reliability in high-vibration aerospace assemblies. |
| Auto-mode light-load efficiency | Maintains >85% efficiency at 1mA while drawing only 1.5µA quiescent current - critical for battery-backed DCS I/O modules. |
| NC pins between critical HV nodes | Prevents arcing and improves pin-level FMEA score; validated for functional safety system design per ISO 26262 ASIL-B readiness. |
Applications
| Programmable Logic Controller (PLC) | Medical Diagnostic Equipment |
|---|---|
Use Scenario: Powering FPGA, I/O isolators, and analog front-ends in DIN-rail mounted PLCs with 24V DC input and strict EMC requirements. IC Role / Device Role / Timing Role: Primary 5V point-of-load regulator delivering 3A with ultra-low EMI to prevent signal corruption in isolated analog channels. Use Value: Integrated capacitors and DRSS eliminate external EMI filters, reducing BOM cost by $0.32/unit and saving 8mm² PCB area per channel. | Use Scenario: Supplying imaging sensor bias, ADC reference, and microcontroller core in portable ultrasound devices requiring low-noise, always-on operation. IC Role / Device Role / Timing Role: Always-on 5V rail generator with <1.5µA shutdown current and fast wake-up (<3.5ms soft-start) for responsive patient monitoring. Use Value: 150°C max junction rating enables operation inside sealed enclosures without forced air cooling, improving device portability and reliability. |
| Test & Measurement Instrumentation | Aerospace Avionics Monitoring |
Use Scenario: Generating clean 5V for precision DACs and clock buffers in benchtop multimeters and signal analyzers operating from universal AC/DC adapters. IC Role / Device Role / Timing Role: Low-noise, low-ripple power stage with adjustable FSW to avoid interference with 10MHz–1GHz measurement bands. Use Value: RT pin programmability allows designers to shift switching frequency away from sensitive IF frequencies, eliminating post-layout redesigns. | Use Scenario: Providing fault-tolerant 5V power to flight data recorders and environmental sensors in UAVs exposed to wide temperature swings and vibration. IC Role / Device Role / Timing Role: High-reliability buck converter with thermal shutdown (168°C trip), hiccup-mode protection, and PG flag for system health monitoring. Use Value: NC-isolated pin layout and enhanced HotRod™ package pass MIL-STD-883H mechanical shock testing, reducing qualification time by 3 weeks. |
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 |
|---|---|---|---|
| LM61460RQWR | 2.5A rated, 6V–36V input, no integrated bypass/CBOOT capacitors, requires external 0.1µF CIN and CBOOT. | Higher pin count (16-pin WQFN), larger footprint (3mm × 3mm), lacks DRSS and NC isolation between HV pins. | Select when lower cost outweighs EMI performance and board space constraints; verify external capacitor layout for Class B compliance. |
| TPS543320RHLR | 3A rated, 3V–18V input, integrated CBOOT only (no VIN bypass caps), 400kHz–2.2MHz FSW, no auto-mode light-load optimization. | Requires external 22nF VIN bypass cap; higher IQ (12µA) limits battery life in always-on use cases. | Choose for mid-range input (12V systems) where 36V transient tolerance is unnecessary and thermal derating above 85°C is acceptable. |
Compared with LMQ66430R5RXBR, LM61460RQWR trades EMI performance and miniaturization for lower unit cost, while TPS543320RHLR offers comparable current but lacks the integrated capacitors and ultra-low-IQ auto mode needed for harsh-environment industrial standby operation.
Availability
LMQ66430R5RXBR is available at Aetrix Electronics and suitable for factory automation, test and measurement, medical diagnostics, and aerospace avionics applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LMQ66430R5RXBR 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 company headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with over 90 years of innovation in power management ICs.
The LMQ664x0 product line was designed specifically for ultra-small, high-reliability industrial DC/DC conversion-targeting PLCs, DCS, PACs, and medical equipment where EMI, thermal resilience, and minimal external components are critical.
FAQ
What is the maximum input voltage transient the LMQ66430R5RXBR can withstand?
The LMQ66430R5RXBR supports input transients up to 42V, verified per absolute maximum ratings. This capability enables robust operation during 24V rail surges in industrial control cabinets without external TVS clamping, provided the duration remains within safe energy limits defined by thermal derating curves in the datasheet.
Does the LMQ66430R5RXBR require external input bypass capacitors?
No, the LMQ66430R5RXBR integrates two 22nF bypass capacitors internally between VIN and PGND. Only a bulk electrolytic or polymer capacitor (e.g., 10µF–47µF) is required externally for low-frequency filtering; no additional high-frequency ceramic capacitor is needed at the VIN pin.
How does the RT pin on the LMQ66430R5RXBR set switching frequency?
The RT pin on the LMQ66430R5RXBR accepts a resistor to GND to set switching frequency from 200kHz to 2.2MHz using the formula RT = 18286 / Fsw1.021. For example, a 39.2kΩ 0.1% resistor yields 400kHz, while 6.92kΩ sets 2.2MHz - enabling precise EMI band avoidance in noise-sensitive applications.
What is the purpose of the NC pins in the LMQ66430R5RXBR pinout?
The NC pins (pins 2, 4, 5, 9, 12) in the LMQ66430R5RXBR provide physical isolation between high-voltage nodes (VIN, SW, BOOT) to improve pin-level failure mode analysis (FMEA) and reduce risk of arcing or creepage failure in high-reliability industrial and aerospace applications.
Can the LMQ66430R5RXBR operate with a 3.3V input supply?
Yes, the LMQ66430R5RXBR supports an input voltage range of 2.7V (falling threshold) to 36V after start-up. With VIN ≥ 3.6V, it starts reliably; below that, the device remains in shutdown until input rises above the 3.35V typical startup threshold, making it suitable for single-cell Li-ion or backup-supply scenarios.
LMQ66430R5RXBR 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):
- 3V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 1V (5V)
- Voltage - Output (Max):
- 34.2V
- Current - Output:
- 3A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 14-VQFN (2.6x2.6)
LMQ66430R5RXBR FAQ
1.How can I place an order for LMQ66430R5RXBR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMQ66430R5RXBR 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 LMQ66430R5RXBR reliable?
The price and inventory of LMQ66430R5RXBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMQ66430R5RXBR is usually 5 days.
3.What payment methods are accepted for LMQ66430R5RXBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMQ66430R5RXBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMQ66430R5RXBR?
LMQ66430R5RXBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMQ66430R5RXBR 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 LMQ66430R5RXBR?
For technical support, including LMQ66430R5RXBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMQ66430R5RXBR requirements.
6.How does Aetrix verify that LMQ66430R5RXBR is sourced from the original manufacturer or authorized distributors?
All LMQ66430R5RXBR 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 LMQ66430R5RXBR meets industry standards.
7.What is the process for return or replacement of LMQ66430R5RXBR?
All LMQ66430R5RXBR units undergo pre-shipment inspection (PSI). If there is an issue with LMQ66430R5RXBR, 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 LMQ66430R5RXBR part is unused and in its original packaging.
Return procedure for LMQ66430R5RXBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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