Texas Instruments LM61435AASQRJRRQ1

Overview

LM61435AASQRJRRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous step-down DC-DC converter delivering up to 3.5 A output current across a 3-V to 36-V input range, with ±1% total output regulation accuracy, spread-spectrum EMI reduction, and adjustable switching frequency (200 kHz–2.2 MHz). It powers infotainment head units and ADAS camera modules requiring low-noise, high-reliability power conversion.

For engineers reviewing the LM61435AASQRJRRQ1 datasheet, LM61435AASQRJRRQ1 pinout, LM61435AASQRJRRQ1 application, or LM61435AASQRJRRQ1 equivalent, key selection criteria include its HotRod™ VQFN-HR package for ultra-low EMI, integrated high-side/low-side MOSFETs (R_DS(ON) = 41 mΩ / 21 mΩ), 7-µA no-load quiescent current, and functional safety documentation support.

Technical Context

The LM61435AASQRJRRQ1 implements peak-current-mode control with auto-mode frequency foldback, enabling seamless PWM-to-PFM transition and 7-µA unloaded current draw. Its dual VIN pins (VIN1/VIN2) and parallel input path minimize parasitic inductance, while RBOOT-adjustable SW node rise time and pseudo-random spread spectrum reduce conducted emissions.

It integrates a 3.3-V internal LDO (VCC), precision enable/sync input with 1.263-V threshold and 24–32% hysteresis, and a robust PGOOD output with 94–96.5% UV and 105–110% OV thresholds. Thermal shutdown triggers at 158–180°C with 10°C hysteresis, supporting operation up to +150°C junction temperature.

Key Specifications

Pinout & Package

LM61435AASQRJRRQ1 uses a 14-pin VQFN-HR (RJR) package, 4.00 mm × 3.50 mm, with exposed thermal pad. The HotRod™ layout minimizes switch-node ringing and improves thermal performance (R_θJA = 25°C/W on 4-layer board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down converter applications.

Compared with LM61435AASQRJRRQ1, the LM61435AANQRJRRQ1 trades EMI performance for lower unit cost, while the LM61440QRJRRQ1 offers higher current headroom with identical footprint-both preserve thermal and layout continuity but differ in regulatory compliance and power ceiling.

Availability

LM61435AASQRJRRQ1 is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera systems, and body electronics requiring stable component supply, long-term lifecycle assurance, and AEC-Q100-compliant sourcing.

Supply support for LM61435AASQRJRRQ1 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 ICs, with decades of automotive qualification expertise and broad power management portfolio.

The LM61435-Q1 product line delivers high-efficiency, low-EMI DC-DC converters optimized for automotive subsystems-including infotainment, ADAS, and body electronics-where reliability, thermal robustness, and EMI compliance are mandatory.

FAQ

What is the maximum input voltage the LM61435AASQRJRRQ1 can withstand during load dump events?

The LM61435AASQRJRRQ1 supports 42-V absolute maximum input voltage per its AEC-Q100 qualification, enabling direct connection to automotive 12-V battery systems without external transient voltage suppression. This rating applies to VIN1 and VIN2 pins simultaneously and covers short-duration load dump pulses defined in ISO 7637-2, simplifying front-end protection design for head units and ADAS ECUs.

Does the LM61435AASQRJRRQ1 support fixed-output voltage configurations?

Yes, the LM61435AASQRJRRQ1 supports factory-programmed 3.3-V fixed output in addition to adjustable operation (1 V to 95% of VIN). The "AAS" suffix denotes the spread-spectrum variant with adjustable output; fixed-voltage versions use different orderable part numbers (e.g., LM61435AFSQRJRRQ1 for FPWM + fixed 3.3 V). No external resistors are needed for the fixed option.

How does the RBOOT pin affect EMI performance in the LM61435AASQRJRRQ1?

The RBOOT pin on the LM61435AASQRJRRQ1 connects to CBOOT through an external resistor that directly controls the SW node rise time-slower rise times reduce high-frequency harmonics and conducted EMI. With RBOOT = 0 Ω, t_RISE is 2.15 ns (10%–80%); increasing resistance to 100 Ω extends it to 2.7 ns. This adjustment allows fine-tuning of EMI vs. efficiency trade-offs without changing layout or components.

Can the LM61435AASQRJRRQ1 be synchronized to an external clock, and what happens to its light-load behavior?

Yes, the EN/SYNC pin accepts external clock signals (200 kHz–2.2 MHz) on its rising edge to synchronize switching frequency. When synchronized, the LM61435AASQRJRRQ1 disables Auto-mode frequency foldback and operates exclusively in forced PWM (FPWM), eliminating PFM mode. This ensures deterministic switching for noise-sensitive systems but increases light-load quiescent current from 7 µA to ~18 µA.

What thermal metrics define the LM61435AASQRJRRQ1's power dissipation capability on a standard PCB?

The LM61435AASQRJRRQ1 has a junction-to-ambient thermal resistance (R_θJA) of 25°C/W on a 4-layer JEDEC board-enabling 3.5-A operation at +105°C ambient with proper copper pour and thermal vias. Its junction-to-board (R_θJB) is 19.2°C/W and junction-to-case (top) is 26.1°C/W, confirming strong heat transfer to the PCB. These values assume the exposed thermal pad is fully soldered to inner ground planes.