Texas Instruments LMR33620CQ5RNXRQ1

Overview

LMR33620CQ5RNXRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-qualified synchronous step-down DC/DC converter delivering 2 A output current with fixed 5-V output, 3.8–36-V input range, 2.1-MHz switching frequency, and peak efficiency >95%. It integrates high- and low-side MOSFETs (75 mΩ/50 mΩ), precision enable, power-good flag, and operates from –40°C to +125°C ambient for infotainment USB charging.

For engineers reviewing the LMR33620CQ5RNXRQ1 datasheet, LMR33620CQ5RNXRQ1 pinout, LMR33620CQ5RNXRQ1 application, or LMR33620CQ5RNXRQ1 equivalent, key selection considerations include its fixed 5-V output, 2.1-MHz operation in compact 3 mm × 2 mm VQFN with wettable flanks, automotive thermal and ESD robustness (HBM ±2500 V), and functional safety documentation support.

Technical Context

The LMR33620CQ5RNXRQ1 uses peak-current-mode control with automatic PFM/PWM mode transition to maintain high light-load efficiency. Its 68-ns minimum on-time enables high VIN-to-VOUT step-down ratios, such as regulating 5 V from 3.8 V input.

It features integrated loop compensation, precision enable thresholds (1.231 V typical turn-on, 100-mV hysteresis), and a dedicated open-drain power-good flag with glitch filtering (60–170 µs) referenced to the 1-V internal feedback reference - configured for fixed 5-V output via internal resistor divider.

Key Specifications

Pinout & Package

LMR33620CQ5RNXRQ1 is housed in a 12-pin VQFN (RNX) package measuring 3.00 mm × 2.00 mm × 0.85 mm with wettable flanks for automated optical inspection (AOI) and improved solder joint reliability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR33620BQRNX, the LMR33620CQ5RNXRQ1 enables smaller passive components and better transient response due to 2.1-MHz operation; versus TPS54360BQDDARQ1, it delivers higher efficiency, lower EMI, and built-in monitoring features at the cost of fixed output and narrower VIN range.

Availability

LMR33620CQ5RNXRQ1 is available at Aetrix Electronics and suitable for automotive infotainment, telematics, and ADAS applications requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for LMR33620CQ5RNXRQ1 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-grade power management ICs with over 40 years of automotive qualification experience.

The LMR336x0-Q1 product line delivers compact, high-efficiency synchronous buck regulators optimized for automotive subsystems demanding AEC-Q100 reliability, low EMI, and functional safety readiness.

FAQ

What is the output voltage configuration of the LMR33620CQ5RNXRQ1?

The LMR33620CQ5RNXRQ1 is factory-configured with a fixed 5-V output. Unlike adjustable versions (e.g., LMR33620AQRNX), it does not require external feedback resistors - the FB pin is internally connected to a precision voltage divider referencing the 1-V internal bandgap. This simplifies design, improves accuracy (±1.5% over temperature and line/load), and reduces PCB area.

Does the LMR33620CQ5RNXRQ1 support functional safety certification?

Yes, the LMR33620CQ5RNXRQ1 is functional safety-capable. Texas Instruments provides documentation including FMEDA reports, FIT rate data (126.5 FIT), and safety analysis guidance to support ISO 26262 ASIL-B system-level development. The device includes diagnostic features such as power-good flag, thermal shutdown, and cycle-by-cycle current limiting - all documented in the functional safety manual SNVSB27C.

What package type and dimensions does the LMR33620CQ5RNXRQ1 use?

The LMR33620CQ5RNXRQ1 uses a 12-pin VQFN package (RNX variant) with nominal body size 3.00 mm × 2.00 mm × 0.85 mm and wettable flanks. This ultra-compact HotRod™ package minimizes parasitic inductance, supports automated optical inspection, and enables high-density automotive PCB layouts - especially critical for space-constrained modules like camera ECUs and instrument clusters.

How does the LMR33620CQ5RNXRQ1 manage efficiency across load conditions?

The LMR33620CQ5RNXRQ1 achieves >95% peak efficiency at medium loads and maintains >85% efficiency at 10-mA output by automatically transitioning between PWM (heavy load) and PFM with diode emulation (light load). Its integrated 75-mΩ/50-mΩ MOSFETs, low 25-µA operating IQ, and valley-current detection eliminate reverse inductor current - reducing switching and conduction losses across the full 0–2-A range.

Can the LMR33620CQ5RNXRQ1 operate with input voltage as low as 3.8 V while delivering 5 V output?

No - the LMR33620CQ5RNXRQ1 cannot regulate 5 V output from 3.8 V input because the minimum input must exceed the output voltage plus dropout losses. With 5-V output and typical RDS(on) losses, the practical minimum VIN is ~5.3 V. However, the device *can* regulate 3.3 V from 3.8 V input (as confirmed in Section 7.1), making the 3.3-V variant (LMR33620CQ3RNX) appropriate for ultra-low VIN applications.