Texas Instruments LMQ644A0QRXARQ1

Overview

LMQ644A0QRXARQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter supporting dual 5 A/5 A outputs or stackable 10 A operation, with 3 V to 36 V input range, 0.8 V to 20 V adjustable output, and 50 ns minimum on-time for high VIN/VOUT step-down. It delivers >95% efficiency at 8 A (VIN=12 V, VOUT=5 V) in single-output mode and targets infotainment power rails.

For engineers reviewing the LMQ644A0QRXARQ1 datasheet, LMQ644A0QRXARQ1 pinout, LMQ644A0QRXARQ1 application, or LMQ644A0QRXARQ1 equivalent, key selection criteria include its dual-output current rating (5 A/5 A), wettable-flank RXA package, 100 kHz–2.2 MHz programmable switching frequency, integrated 22 nF bypass capacitors, and functional safety documentation support.

Technical Context

The LMQ644A0QRXARQ1 employs interleaved, stackable current-mode control enabling precise current sharing across up to six phases and fast transient response. Its architecture supports both independent dual-output regulation and synchronized single-output stacking with external clock synchronization (SYNCIN/SYNCOUT).

It integrates four 22 nF high-frequency VIN-to-GND bypass capacitors, symmetrical input pins with >1 mm ground clearance, and Dual Random Spread Spectrum (±10%) to meet CISPR 25 Class 5 EMI requirements. The bias pin enables output-powered operation, achieving 9 µA no-load quiescent current.

Key Specifications

Pinout & Package

LMQ644A0QRXARQ1 uses the RXA package: 24-pin enhanced HotRod QFN with wettable flanks (4.0 mm × 5.0 mm body), optimized for automated optical inspection and thermal performance (R_θJA = 34.2°C/W on JEDEC board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output buck converter applications.

Compared with LMQ644A0QRXARQ1, the LMQ644A2QRXARQ1 offers higher current headroom for future-proofing or thermally constrained layouts, while the LMQ64480QRXARQ1 provides identical pinout and feature set at reduced current rating-enabling scalable platform design across power tiers.

Availability

LMQ644A0QRXARQ1 is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and digital cluster displays requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant sourcing.

Supply support for LMQ644A0QRXARQ1 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 specializing in analog and embedded processing technologies, with leadership in automotive power management ICs and functional safety solutions.

The LMQ644xx-Q1 product line was designed specifically for high-density, low-EMI automotive DC/DC conversion - targeting infotainment, ADAS, and body electronics where reliability, thermal performance, and regulatory compliance are critical.

FAQ

What is the maximum output current capability of the LMQ644A0QRXARQ1 in dual-output mode?

The LMQ644A0QRXARQ1 is rated for continuous dual-output operation at 5 A per channel (10 A total). It supports stacking multiple units in interleaved configuration for higher current, with validated 10 A stack performance and accurate current sharing enabled by its current-mode control architecture.

Does the LMQ644A0QRXARQ1 support fixed 3.3 V and 5 V outputs without external feedback resistors?

Yes, the LMQ644A0QRXARQ1 supports fixed 3.3 V and 5 V outputs via pin-strapping: connect FB1 or FB2 to AGND for 3.3 V, or to VCC through a 10 kΩ resistor for 5 V. This eliminates external resistors for standard rails while retaining full adjustability (0.8 V–20 V) via resistive dividers when needed.

How does the LMQ644A0QRXARQ1 achieve CISPR 25 Class 5 EMI compliance?

The LMQ644A0QRXARQ1 achieves CISPR 25 Class 5 compliance through integrated design elements: four 22 nF high-frequency VIN-to-GND bypass capacitors, symmetrical input pin layout with >1 mm ground clearance, Dual Random Spread Spectrum (±10%), and enhanced HotRod QFN packaging with wettable flanks - collectively reducing peak emissions without external filtering.

What thermal protection features are included in the LMQ644A0QRXARQ1?

The LMQ644A0QRXARQ1 includes thermal shutdown at 168°C junction temperature with 10°C hysteresis, hiccup-mode overcurrent protection with configurable wait/restart timing, and precision thermal monitoring via its internal die temperature sensing - all documented for functional safety system integration.

Can the LMQ644A0QRXARQ1 operate with input voltage as low as 3 V, and how does it maintain regulation?

Yes, the LMQ644A0QRXARQ1 operates down to 3 V input. At low VIN, it automatically reduces switching frequency to maintain regulation near 100% duty cycle - enabling stable output during automotive cold-crank events without dropout, supported by its 50 ns minimum on-time and adaptive control loop.