Texas Instruments LM62440ALPQRJRRQ1

Overview

LM62440ALPQRJRRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous step-down DC-DC converter delivering up to 4 A output current across a 3-V to 36-V input range, with 42-V load dump tolerance, ±1% total output regulation accuracy, and factory-set 400-kHz switching frequency optimized for high efficiency at low frequencies. It serves as the primary power stage in automotive infotainment head units and ADAS domain controllers requiring robust, low-EMI 5-V or 3.3-V rails.

For engineers reviewing the LM62440ALPQRJRRQ1 datasheet, LM62440ALPQRJRRQ1 pinout, LM62440ALPQRJRRQ1 application, or LM62440ALPQRJRRQ1 equivalent, key selection criteria include its 400-kHz fixed-frequency operation, adjustable SW node rise time via RBOOT, FPWM mode enablement, 7-µA no-load quiescent current, and VQFN-HR (14-pin) wettable flank package for automotive thermal and reliability compliance.

Technical Context

The LM62440ALPQRJRRQ1 implements a dual-input, dual-power-ground architecture with integrated high-side (41 mΩ typical R_DS(on)) and low-side (21 mΩ typical R_DS(on)) MOSFETs, enabling efficient 4-A conversion while minimizing PCB layout complexity. Its control loop supports auto-mode frequency foldback and seamless PWM-to-PFM transition, maintaining ≥76% efficiency at 100 µA load with 5-V output.

EMI mitigation is achieved through pseudorandom spread spectrum (2% span), adjustable SW node rise time (2.15–2.7 ns), and HotRod™-derived VQFN-HR package with parallel input paths and minimized switch-node ringing - all validated under conducted EMI testing per CISPR 25 Class 5.

Key Specifications

Pinout & Package

VQFN-HR (14-pin, 4.00 mm × 3.50 mm) package with wettable flanks for automotive-grade solder joint reliability and thermal performance. Exposed thermal pad connected to PGND1/PGND2 for low-impedance heat path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with LM62440BLPQRJRRQ1, the LM62440ALPQRJRRQ1 provides design flexibility via adjustable output voltage but requires external feedback resistors; compared with LM61440ALPQRJRRQ1, it adds AEC-Q100 Grade 1 qualification, 42-V load dump support, and extended thermal range - essential for under-hood automotive deployment.

Availability

LM62440ALPQRJRRQ1 is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera ECUs, and body control modules requiring stable component supply with guaranteed long-term automotive lifecycle support.

Supply support for LM62440ALPQRJRRQ1 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 and embedded processing technologies, with deep expertise in automotive power management ICs and functional safety-compliant design.

The LM62440-Q1 product line delivers high-efficiency, low-EMI synchronous buck converters engineered specifically for automotive power rails - addressing stringent AEC-Q100, CISPR 25, and ASIL-ready system requirements.

FAQ

What is the input voltage start-up threshold for the LM62440ALPQRJRRQ1?

The LM62440ALPQRJRRQ1 requires a minimum input voltage of 3.95 V to initiate startup under nominal conditions. Once operating, it sustains regulation down to 3.0 V input. This 3.95-V threshold ensures reliable turn-on after cold-crank events while maintaining compatibility with standard 12-V automotive battery profiles. The device also supports 42-V load dump transients for up to 400 ms without latch-off or damage.

Does the LM62440ALPQRJRRQ1 support external synchronization?

Yes, the LM62440ALPQRJRRQ1 supports external clock synchronization via the MODE/SYNC pin. It accepts a TTL/CMOS-compatible clock signal between 200 kHz and 2.2 MHz, with valid pulse widths ≥100 ns. When synchronized, the device locks to the external clock within 2048 cycles and maintains spread spectrum operation if enabled. This capability allows timing alignment across multiple rails in domain controllers or radar modules.

How does the RBOOT pin affect EMI performance in the LM62440ALPQRJRRQ1?

The RBOOT pin on the LM62440ALPQRJRRQ1 adjusts the SW node rise time by controlling gate drive strength: a 0-Ω connection yields 2.15 ns (10%–80%), while 100 Ω extends it to 2.7 ns. Slower rise times reduce high-frequency harmonic content and conducted EMI peaks, particularly above 30 MHz. This adjustment is critical for meeting CISPR 25 Class 5 limits without adding ferrite beads or extra filtering components.

What is the thermal resistance specification for the LM62440ALPQRJRRQ1 package?

The LM62440ALPQRJRRQ1 in its VQFN-HR (14-pin) package achieves a junction-to-ambient thermal resistance (R_θJA) of 25°C/W on a standard 4-layer JEDEC board - significantly lower than the 58.7°C/W simulated value due to optimized copper pour and thermal vias. Its junction-to-board (R_θJB) is 19.2°C/W, confirming effective heat transfer to the PCB, which supports continuous 4-A operation at +125°C ambient with proper layout.

Can the LM62440ALPQRJRRQ1 operate in forced PWM (FPWM) mode at light loads?

Yes, the LM62440ALPQRJRRQ1 supports pin-selectable FPWM mode via the MODE/SYNC pin. In FPWM, the device maintains constant 400-kHz switching frequency regardless of load - eliminating frequency modulation artifacts that cause audible noise or interfere with sensitive analog circuits. This mode is especially valuable in infotainment audio subsystems and camera ISPs where consistent switching behavior is mandatory.