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Texas Instruments LMQ66420MC5RXBRQ1
- Part No.:
- LMQ66420MC5RXBRQ1
- Manufacturer:
- Texas Instruments
- Package:
- 14-PowerTFQFN
- Datasheet:
-
LMQ66420MC5RXBRQ1.pdf
- Description:
- IC REG BUCK ADJ/1V 2A 14VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,394
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Product details
Overview
LMQ66420MC5RXBRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous step-down DC/DC converter delivering up to 2A output current at a fixed 5V output, operating from 3.0V to 36V input with 42V load dump tolerance. It integrates VIN bypass and CBOOT capacitors, uses peak current mode control, and achieves >85% efficiency at 1mA in Auto mode for always-on systems such as radar ECUs and infotainment head units.
For engineers reviewing the LMQ66420MC5RXBRQ1 datasheet, LMQ66420MC5RXBRQ1 pinout, LMQ66420MC5RXBRQ1 application, or LMQ66420MC5RXBRQ1 equivalent, key selection considerations include its 2.2MHz fixed switching frequency, integrated EMI-reduction features (DRSS, enhanced HotRod QFN), thermal shutdown at 168°C, power-good flag with 2.5ms activation delay, and precision enable threshold of 1.23V.
Technical Context
The LMQ66420MC5RXBRQ1 implements peak current mode control with auto-mode frequency foldback and seamless PWM-to-PFM transition, enabling ultra-low quiescent current (2µA at 13.5VIN, 0A load) while maintaining regulation across wide input transients. Its ZEN 2 switcher architecture integrates dual 22-nF VIN bypass capacitors and a 0.1-µF CBOOT capacitor internally, eliminating external placement and reducing high-frequency EMI sources.
It supports FPWM or Auto mode selection via the MODE/SYNC pin, includes internal loop compensation, and features NC pins between critical high-voltage nodes (VIN, SW, BOOT) to improve pin-level FMEA robustness. The device operates over –40°C to +150°C junction temperature and withstands 42V automotive load dump and 3VIN cold-crank conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 2A continuous - supports radar sensor modules and display backlight drivers without external current boosting. |
| Input Voltage Range | 3.0V–36V after startup; 42V absolute max - handles full automotive battery range including cold crank (3VIN) and load dump. |
| Output Voltage | Fixed 5.00V ±0.6% - eliminates external feedback resistors and ensures stable USB-peripheral or MCU I/O rail supply. |
| Switching Frequency | Fixed 2.2MHz - enables use of small 1µH inductors and avoids AM-band interference in infotainment systems. |
| Quiescent Current | 2µA at 13.5VIN, 0A load - meets ISO 26262 ASIL-B standby power requirements for always-on ADAS domains. |
| Thermal Shutdown | 168°C trip with 20°C hysteresis - protects against sustained overload in enclosed ECU enclosures without derating. |
| EMI Reduction | Dual Random Spread Spectrum (DRSS) + enhanced HotRod™ QFN - reduces peak emissions by >10dB, aiding CISPR 25 Class 5 compliance. |
Pinout & Package
LMQ66420MC5RXBRQ1 uses the RXB (VQFN-FCRLF, 14-pin) package: 2.6mm × 2.6mm enhanced HotRod™ QFN with wettable flanks and corner anchor pins for reliable solder joint inspection and mechanical robustness in automotive vibration environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 EN/UVLO | Enable input with precision UVLO | Starts regulation when VIN ≥3.35V; shuts down below 2.7V; supports direct connection to VIN for simple on/off control. |
| 3 VIN | Main power input | Internally connects two 22-nF bypass caps to PGND; accepts up to 42V transient; requires external bulk capacitance only for low-frequency ripple. |
| 6 PGND | Power ground return | Low-inductance path for high di/dt switch currents; must be connected to system GND with short, wide copper pour. |
| 7 SW | Switch node | Drives external power inductor; minimized ringing due to bond-wire-free HotRod layout and optimized pin placement. |
| 8 BOOT | Bootstrap supply | Internally connects 0.1-µF cap to SW; eliminates need for external bootstrap capacitor and routing. |
| 10 VCC | Internal LDO output | 3.3V ±3% regulated supply for control circuitry; can power logic-level PG pull-up resistor (10kΩ typical). |
| 11 VOUT/FB | Fixed 5V output / feedback node | Direct connection to 5V rail; no external divider needed; FB function disabled in fixed-VOUT variants. |
| 13 MODE/SYNC | Mode selection / clock sync input | Selects Auto (PFM) or FPWM mode; accepts 0.2–2.5MHz external clock for synchronized multi-rail systems. |
| 14 PG | Open-drain power-good flag | Asserts high after 2.5ms soft-start; provides reset timing for downstream MCUs; deglitched with 40µs filter. |
| 2,4,5,9,12 NC | No-connect terminals | Isolate high-voltage nodes (VIN, SW, BOOT); improve pin-level FMEA by preventing unintended shorts during board flex or contamination. |
| GND/DAP | Thermal pad / ground | Mandatory solder connection to PCB GND plane; primary thermal path (RθJB = 26.2°C/W); improves power dissipation by >40% vs. standard QFN. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated VIN bypass & CBOOT capacitors | Eliminates two external 0402/0603 MLCCs, reduces board area by ≥1.2mm², and removes high-frequency EMI coupling paths. |
| ZEN 2 switcher architecture | Combines DRSS, optimized HotRod pinout, and NC guard pins to achieve CISPR 25 Class 5 compliance without common-mode chokes. |
| Auto mode with frequency foldback | Reduces switching frequency under light load to maintain >85% efficiency at 1mA, cutting standby power in always-on ADAS sensors. |
| Enhanced HotRod™ QFN with wettable flanks | Enables automated optical inspection (AOI) of solder joints and improves mechanical reliability under thermal cycling and vibration stress. |
| Power-good flag with built-in delay | Provides clean 2.5ms-debounced reset signal to microcontrollers-replaces discrete supervisor ICs in cost-sensitive body electronics designs. |
Applications
| Radar ECU Power Supply | Infotainment Head Unit Core Rail |
|---|---|
|
Use Scenario: Powers 77GHz radar transceiver ASICs requiring stable 5V at ≤1.5A with ultra-low noise and fast transient response. IC Role / Device Role / Timing Role: Primary 5V buck regulator supplying RF front-end, DSP core, and CAN interface; delivers <100ns load-step response with integrated compensation. Use Value: Integrated bypass caps and DRSS suppress switching noise near 77GHz band; 2.2MHz operation avoids interference with radar chirp timing. |
Use Scenario: Supplies 5V rail to SoC, audio codec, and USB peripherals in automotive head units with strict EMI limits. IC Role / Device Role / Timing Role: Secondary voltage regulator downstream of main 12V–5V conversion; synchronizable via MODE/SYNC to avoid beat frequencies with display clocks. Use Value: SYNC capability enables deterministic noise spectrum alignment; wettable flanks ensure long-term solder joint integrity in thermally cycled dashboards. |
| eCall Module Backup Power | LED Lighting Control Unit |
|
Use Scenario: Provides always-on 5V supply to eCall cellular modem and GNSS receiver during vehicle ignition-off state. IC Role / Device Role / Timing Role: Low-quiescent-current buck converter operating in Auto mode; maintains regulation during battery voltage sag to 3.0V. Use Value: 2µA shutdown current extends backup battery life; 42V tolerance prevents latch-up during jump-start events. |
Use Scenario: Powers LED driver ICs and microcontroller in adaptive front-lighting systems (AFS) with PWM dimming inputs. IC Role / Device Role / Timing Role: Fixed 5V source for logic and gate drivers; PG flag signals MCU when output is valid post-soft-start. Use Value: Internal soft-start (3.5ms) prevents inrush into LED string capacitance; NC pins isolate SW from EN/PG to prevent false resets during PWM bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM61480QRVJRQ1 | 3A rated, 400kHz/2.1MHz selectable, no integrated bypass caps, larger 3mm × 3mm VQFN | Higher current headroom but requires external 22nF VIN bypass and 0.1µF CBOOT; less compact layout | Choose when >2A peak load is expected and board space allows larger package and extra passives. |
| TPS62865ARGRR | 3A, 2.2MHz fixed, no AEC-Q100 qualification, no integrated capacitors, 2.5mm × 2.5mm WQFN | Lacks automotive qualification and integrated EMI-reduction features; lower thermal rating (125°C TJ max) | Consider only for non-automotive industrial applications where cost is prioritized over qualification and EMI robustness. |
Compared with LMQ66420MC5RXBRQ1, LM61480QRVJRQ1 offers higher current and flexible frequency but increases BOM count and layout complexity, while TPS62865ARGRR sacrifices automotive qualification and integrated EMI mitigation-making LMQ66420MC5RXBRQ1 the optimal choice for space-constrained, safety-critical automotive 5V rails.
Availability
LMQ66420MC5RXBRQ1 is available at Aetrix Electronics and suitable for advanced driver assistance systems (radar ECUs), infotainment head units, eCall modules, and adaptive lighting control units requiring stable component supply across extended automotive temperature and lifetime requirements.
Supply support for LMQ66420MC5RXBRQ1 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 automotive-grade power management solutions, with decades of automotive qualification expertise and AEC-Q100 process validation.
The LMQ664x0-Q1 product line was designed specifically for ultra-compact, low-EMI, always-on automotive power rails-including ADAS sensors, infotainment SoCs, and body control modules-where board space, thermal performance, and CISPR 25 compliance are critical.
FAQ
What is the maximum input voltage the LMQ66420MC5RXBRQ1 can withstand during automotive load dump?
The LMQ66420MC5RXBRQ1 supports 42V absolute maximum input voltage per its Absolute Maximum Ratings table, enabling reliable operation during ISO 7637-2 Pulse 5a load dump events without external TVS clamping. This rating applies across the full –40°C to +150°C junction temperature range and is validated per AEC-Q100 stress testing protocols.
Does the LMQ66420MC5RXBRQ1 require external input bypass capacitors?
No-the LMQ66420MC5RXBRQ1 integrates two 22-nF VIN bypass capacitors internally between VIN and PGND, eliminating the need for external high-frequency ceramic capacitors. Only bulk capacitance (e.g., 10µF tantalum or polymer) is recommended at the VIN pin for low-frequency stability and hold-up time.
How does the MODE/SYNC pin function on the LMQ66420MC5RXBRQ1?
The MODE/SYNC pin on the LMQ66420MC5RXBRQ1 serves three roles: (1) logic-high sets FPWM mode, (2) logic-low selects Auto (PFM) mode, and (3) AC-coupled external clock input (0.2–2.5MHz) locks the internal oscillator for synchronized multi-rail operation. No external pull-up/down is required-internal biasing ensures defined state at power-up.
What is the purpose of the NC pins on the LMQ66420MC5RXBRQ1 package?
The NC pins (2, 4, 5, 9, 12) on the LMQ66420MC5RXBRQ1 serve as physical isolation barriers between high-voltage nodes (VIN, SW, BOOT) to reduce risk of field-induced breakdown or solder bridging. They are part of TI's pin-level FMEA optimization-improving reliability in high-vibration automotive environments without adding cost or complexity.
Can the LMQ66420MC5RXBRQ1 be used in applications requiring functional safety compliance?
Yes-the LMQ66420MC5RXBRQ1 is functional safety-capable with documentation available to support ISO 26262 ASIL-B system design. It includes diagnostic features such as power-good flag with UV/OV detection, thermal shutdown with hysteresis, and precise enable thresholds-all verified under AEC-Q100 Grade 1 conditions (–40°C to +125°C ambient).
LMQ66420MC5RXBRQ1 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):
- 18V
- Current - Output:
- 2A
- Frequency - Switching:
- 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 14-VQFN (2.6x2.6)
LMQ66420MC5RXBRQ1 FAQ
1.How can I place an order for LMQ66420MC5RXBRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LMQ66420MC5RXBRQ1 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 LMQ66420MC5RXBRQ1 reliable?
The price and inventory of LMQ66420MC5RXBRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMQ66420MC5RXBRQ1 is usually 5 days.
3.What payment methods are accepted for LMQ66420MC5RXBRQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMQ66420MC5RXBRQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMQ66420MC5RXBRQ1?
LMQ66420MC5RXBRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMQ66420MC5RXBRQ1 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 LMQ66420MC5RXBRQ1?
For technical support, including LMQ66420MC5RXBRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMQ66420MC5RXBRQ1 requirements.
6.How does Aetrix verify that LMQ66420MC5RXBRQ1 is sourced from the original manufacturer or authorized distributors?
All LMQ66420MC5RXBRQ1 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 LMQ66420MC5RXBRQ1 meets industry standards.
7.What is the process for return or replacement of LMQ66420MC5RXBRQ1?
All LMQ66420MC5RXBRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LMQ66420MC5RXBRQ1, 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 LMQ66420MC5RXBRQ1 part is unused and in its original packaging.
Return procedure for LMQ66420MC5RXBRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LMQ66420MC5RXBRQ1 Tags
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