Texas Instruments LMQ644A2QRXARQ1

Overview

LMQ644A2QRXARQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter supporting dual 6 A/6 A outputs or stackable 12 A operation, with 3 V to 36 V input range, 0.8 V to 20 V adjustable output, 50 ns minimum on-time, and integrated 22 nF VIN-to-GND bypass capacitors - deployed in infotainment head units and ADAS power rails.

For engineers reviewing the LMQ644A2QRXARQ1 datasheet, LMQ644A2QRXARQ1 pinout, LMQ644A2QRXARQ1 application, or LMQ644A2QRXARQ1 equivalent, key selection criteria include its dual-output current capability (6 A per channel), wettable-flank RXA package for automated optical inspection, CISPR 25 Class 5 EMI compliance, and bias-powered 9 µA no-load quiescent current for battery-sensitive automotive systems.

Technical Context

The LMQ644A2QRXARQ1 employs interleaved current-mode control with stackable architecture supporting up to six phases for scalable current delivery. Its 50 ns t_ON(min) enables direct 12 V/24 V-to-low-voltage conversion without pre-regulation, while dual random spread spectrum (±10%) reduces peak EMI emissions across 100 kHz–2.2 MHz switching frequency range.

It integrates four 22 nF high-frequency bypass capacitors, symmetrical VIN pin layout (>1 mm clearance to ground), and wettable-flank 24-pin RXA QFN package optimized for thermal performance (R_θJA = 17 °C/W on EVM) and manufacturability. The device supports both FPWM and diode emulation modes via SYNC pin configuration and features independent ENABLE/PGOOD per channel.

Key Specifications

Pinout & Package

LMQ644A2QRXARQ1 uses a 24-pin RXA (VQFN-FCRLF) package with wettable flanks, 4.0 mm × 5.0 mm body size, and exposed thermal pad (PGND4) for low-impedance heat sinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMQ644A2QRXARQ1, the LMQ644A0QRXARQ1 and LMQ64480QRXARQ1 share the RXA package, pinout, and feature set but scale down current capability and thermal derating - making them viable alternatives only when full 6 A/channel output is not required, avoiding overdesign and cost premium.

Availability

LMQ644A2QRXARQ1 is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and digital instrument clusters requiring stable component supply across extended vehicle lifecycles.

Supply support for LMQ644A2QRXARQ1 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 AEC-Q100 compliance, thermal robustness, and stackable scalability are mandatory.

FAQ

What is the maximum output current capability of the LMQ644A2QRXARQ1 in dual-output mode?

The LMQ644A2QRXARQ1 delivers up to 6 A per channel in dual-output mode, with independent current limiting and thermal monitoring for each rail. Its 11 A high-side peak current limit and 7.7 A low-side valley limit ensure robust operation under transient overload, and stacking multiple LMQ644A2QRXARQ1 devices enables scalable current delivery up to 36 A across six phases.

Does the LMQ644A2QRXARQ1 support synchronization with external clock sources?

Yes, the LMQ644A2QRXARQ1 supports external clock synchronization via its SYNC pin, accepting input frequencies from 320 kHz to 2.4 MHz depending on RT resistor setting. In single-output primary configuration, it also provides a SYNC_OUT signal to coordinate timing with secondary devices, ensuring phase-aligned switching for optimal ripple cancellation and EMI reduction.

How does the LMQ644A2QRXARQ1 achieve CISPR 25 Class 5 EMI compliance?

The LMQ644A2QRXARQ1 achieves CISPR 25 Class 5 compliance through integrated hardware-level EMI mitigation: symmetrical VIN pin layout (>1 mm ground clearance), four internal 22 nF high-frequency bypass capacitors, Dual Random Spread Spectrum (±10% frequency hopping), and enhanced HotRod QFN packaging with wettable flanks - eliminating need for external EMI filters in most automotive layouts.

What is the purpose of the BIAS pin on the LMQ644A2QRXARQ1?

The BIAS pin on the LMQ644A2QRXARQ1 allows the device to be powered from its own output rail, reducing input-side quiescent current to just 9 µA in no-load dual-output mode. This significantly extends battery runtime in always-on automotive modules such as telematics control units and body controllers during vehicle sleep states.

Can the LMQ644A2QRXARQ1 operate with input voltage as low as 3 V?

Yes, the LMQ644A2QRXARQ1 operates down to 3 V input - critical for automotive cold-crank conditions. Its adaptive frequency scaling automatically reduces switching frequency when minimum on-time or off-time limits would otherwise prevent regulation, maintaining stable output even at near-100% duty cycle during deep voltage sags.