Texas Instruments LMR33620CQRNXTQ1

Overview

LMR33620CQRNXTQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-qualified synchronous step-down DC/DC converter delivering 2 A output current across 3.8 V to 36 V input, with adjustable 1 V–24 V output and fixed 2.1 MHz switching frequency. It integrates 75 mΩ/50 mΩ power MOSFETs, peak-current-mode control, and a 68 ns minimum on-time for high-efficiency operation in infotainment USB charging and telematics control units.

For engineers reviewing the LMR33620CQRNXTQ1 datasheet, LMR33620CQRNXTQ1 pinout, LMR33620CQRNXTQ1 application, or LMR33620CQRNXTQ1 equivalent, key selection criteria include its 2.1 MHz fixed-frequency operation, wettable-flank VQFN package for EMI reduction, precision enable thresholds (1.231 V typical), power-good flag with glitch filtering, and functional safety documentation support.

Technical Context

The LMR33620CQRNXTQ1 implements peak-current-mode control with automatic PFM/PWM mode transition to maintain >95% peak efficiency across load range. Its integrated compensation network eliminates external loop components, while the 68 ns minimum on-time enables high step-down ratios - e.g., regulating 3.3 V from 3.8 V input at 2.1 MHz.

Thermal protection includes thermal shutdown at 165°C with 148°C recovery, cycle-by-cycle current limiting (ISC = 3.5 A typ), hiccup-mode short-circuit response (94 ms off-time), and input UVLO with precision EN thresholds (VEN-H = 1.231 V, VEN-HYS = 100 mV). The device supports hot-swap capability via controlled soft-start (4 ms typical) and power-good flag with ±2% regulation window.

Key Specifications

Pinout & Package

LMR33620CQRNXTQ1 uses a 12-pin VQFN (RNX) package measuring 3.00 mm × 2.00 mm × 0.85 mm with wettable flanks for solder inspection and enhanced thermal performance (R_θJA = 72.5°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR33620CQRNXTQ1, the LMR33620BQRNXTQ1 offers relaxed EMI filtering requirements at the cost of larger passive components, while the TPS543320RHLT adds telemetry and headroom at significantly higher BOM cost and complexity - neither is pin-compatible, but both target the same automotive power rail segment.

Availability

LMR33620CQRNXTQ1 is available at Aetrix Electronics and suitable for automotive infotainment systems, telematics control units, and ADAS camera modules requiring stable component supply with AEC-Q100 qualification and long-term production support.

Supply support for LMR33620CQRNXTQ1 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 manufacturing scale.

The LMR336xx-Q1 product line delivers compact, high-efficiency synchronous buck regulators optimized for automotive subsystems where space, thermal performance, and AEC-Q100 reliability are mandatory - especially infotainment, body electronics, and ADAS edge nodes.

FAQ

What is the switching frequency of the LMR33620CQRNXTQ1?

The LMR33620CQRNXTQ1 operates at a fixed 2.1 MHz switching frequency, as confirmed in the Device Comparison Table and Section 6.5 of the datasheet. This frequency is factory-programmed and non-adjustable, enabling compact magnetics and reduced EMI fundamental energy above the AM radio band. The LMR33620CQRNXTQ1 maintains this frequency across its full input and load range unless entering hiccup or dropout modes.

Does the LMR33620CQRNXTQ1 support adjustable output voltage?

Yes, the LMR33620CQRNXTQ1 supports adjustable output voltage from 1 V to 24 V using an external resistor divider on the FB pin. Its feedback reference voltage is 1.0 V (±1.5%), and the datasheet provides design equations and layout guidance for stable regulation. Fixed-output variants (e.g., 3.3 V or 5 V) exist but are distinct part numbers - the LMR33620CQRNXTQ1 itself is the adjustable version.

What package type and dimensions does the LMR33620CQRNXTQ1 use?

The LMR33620CQRNXTQ1 uses a 12-pin VQFN package (RNX) with nominal dimensions of 3.00 mm × 2.00 mm × 0.85 mm and wettable flanks. This HotRod™ package features symmetrical VIN/PGND pins to cancel magnetic fields and reduce EMI. The package is explicitly listed in the Device Information table and Pin Configuration section of the datasheet, and footprint drawings are provided in the mechanical data appendix.

How does the power-good (PG) flag function on the LMR33620CQRNXTQ1?

The LMR33620CQRNXTQ1 PG pin is an open-drain output that asserts high when output voltage is within ±5% of target (105–110% upper / 90–95% lower thresholds) and holds low during startup, faults, or EN deactivation. It includes a 60–170 µs glitch filter to ignore transient excursions. The LMR33620CQRNXTQ1 PG signal remains valid down to 2 V input, and the pin must be pulled up externally - typically to VCC or VOUT via a 100 kΩ resistor.

Is the LMR33620CQRNXTQ1 qualified for automotive applications?

Yes, the LMR33620CQRNXTQ1 is AEC-Q100 Grade 1 qualified for automotive use, with operating ambient temperature range of –40°C to +125°C. It includes functional safety documentation, thermal shutdown (165°C), cycle-by-cycle current limit, hiccup-mode short-circuit protection, and input UVLO - all validated per automotive stress test standards. The "-Q1" suffix and front-page features section explicitly confirm this qualification.