Texas Instruments LMR38025S5QDRRRQ1

Overview

LMR38025S5QDRRRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter delivering 2.5A continuous output at fixed 5V, operating from 4.2V to 80V input with 40µA quiescent current and 200kHz–2.2MHz adjustable switching frequency - used in 48V mild-hybrid ECU bias supplies.

For engineers reviewing the LMR38025S5QDRRRQ1 datasheet, LMR38025S5QDRRRQ1 pinout, LMR38025S5QDRRRQ1 application, or LMR38025S5QDRRRQ1 equivalent, key selection criteria include its fixed 5V output, spread-spectrum EMI reduction, prebias start-up capability, precision enable threshold (1.1–1.4V), and integrated thermal shutdown at 163°C.

Technical Context

The LMR38025S5QDRRRQ1 implements fixed-frequency peak-current mode control with internal compensation, enabling stable regulation across wide VIN (4.2–80V) and load (0–2.5A) ranges. It supports both PFM for light-load efficiency and forced PWM (FPWM) for constant frequency operation - though this variant is FPWM-disabled per Device Comparison Table.

Its 12-pin WSON package integrates wettable flanks and PowerPAD™ for thermal reliability in automotive under-hood environments. The device features a high-voltage enable pin, open-drain power-good flag with built-in glitch filtering (45µs), and RT/SYNC pin supporting either resistor-programmed frequency or external clock synchronization (300–2100kHz).

Key Specifications

Pinout & Package

LMR38025S5QDRRRQ1 uses a 12-pin WSON (DRR) package with 3mm × 3mm footprint and exposed thermal pad (PowerPAD™) soldered to PCB ground for enhanced thermal dissipation. Wettable flanks support automated optical inspection (AOI) of solder joints in automotive production.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR38025S5QDRRRQ1, the LMR38025FSQDRRRQ1 adds FPWM for tighter regulation at light loads but increases IQ, while the LMR36520S5QDRRRQ1 reduces voltage range and current capability to lower cost - neither is pin-compatible due to differing enable thresholds and internal compensation.

Availability

LMR38025S5QDRRRQ1 is available at Aetrix Electronics and suitable for automotive inverter bias supplies, 48V mild-hybrid ECU power, battery management systems, and automotive DC/DC converter auxiliary rails requiring stable component supply across extended temperature and long product lifecycles.

Supply support for LMR38025S5QDRRRQ1 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 solutions with decades of AEC-Q100 qualification experience.

The LMR38025-Q1 product line delivers high-voltage, low-IQ synchronous buck converters specifically engineered for demanding automotive applications including 48V mild hybrids, battery management, and motor control bias supplies.

FAQ

What is the output voltage configuration of the LMR38025S5QDRRRQ1?

The LMR38025S5QDRRRQ1 is factory-configured for fixed 5.0V output - no external feedback resistors are required. Its FB pin is internally connected to the output stage and must be shorted directly to the VOUT pin per datasheet guidance. This configuration ensures ±0.8% output tolerance over –40°C to +150°C junction temperature and eliminates design variability associated with resistor divider selection.

Does the LMR38025S5QDRRRQ1 support external frequency synchronization?

Yes, the LMR38025S5QDRRRQ1 supports external clock synchronization via its RT/SYNC pin. When driven with a square wave between 300kHz and 2100kHz (with ≥2V high level and ≤0.6V low level), the internal oscillator locks to the external signal. This capability enables EMI reduction through frequency dithering and avoids beat frequencies in multi-converter systems - a key requirement in automotive ADAS and infotainment platforms.

How does the LMR38025S5QDRRRQ1 handle start-up into a prebiased output?

The LMR38025S5QDRRRQ1 supports prebiased start-up, allowing safe activation when the output capacitor is already charged to 5V. During start-up, the device controls high-side switch timing to prevent reverse current flow from VOUT into the SW node. This behavior protects downstream circuitry and ensures reliable operation in systems with hot-pluggable modules or shared bias rails - common in automotive gateway and domain controller architectures.

What thermal performance can be expected from the LMR38025S5QDRRRQ1 in a typical automotive layout?

In a standard 4-layer PCB with 2oz copper and a 300mm² thermal pad connected to internal ground planes, the LMR38025S5QDRRRQ1 achieves RθJA(Eff) ≈ 23.0°C/W. At 2.5A load and 24V input, junction temperature rise remains below 85°C - well within the AEC-Q100 Grade 1 limit of +150°C. The exposed PowerPAD™ and wettable flank design ensure manufacturable, AOI-verifiable solder joints for long-term under-hood reliability.

Is spread-spectrum modulation enabled by default on the LMR38025S5QDRRRQ1?

Yes, spread-spectrum modulation is factory-enabled on the LMR38025S5QDRRRQ1 and cannot be disabled. This pseudorandom frequency dithering reduces peak radiated emissions by up to 10dB, directly supporting compliance with CISPR25 Class 5 requirements for automotive electronics. No external components or configuration pins are needed - the feature operates automatically across the full 200kHz–2.2MHz frequency range.