Texas Instruments LM5149-Q1EVM-400

Overview

LM5149-Q1EVM-400 from Texas Instruments is a fully assembled, automotive-grade evaluation module based on the LM5149-Q1 synchronous buck DC/DC controller. It delivers 12 V at up to 8 A from a 15–72 V input, features 400 kHz free-running switching frequency with external synchronization capability, achieves >95% full-load efficiency at 48 V input, and incorporates dual-random spread spectrum (DRSS) and active EMI filtering (AEF) for CISPR 25 Class 5 compliance.

For engineers reviewing the LM5149-Q1EVM-400 datasheet, LM5149-Q1EVM-400 test setup, LM5149-Q1EVM-400 schematic, LM5149-Q1EVM-400 thermal performance, or LM5149-Q1EVM-400 efficiency curves, this page provides verified electrical characteristics, application circuit context, PCB layout validation, and design-ready performance data for automotive power system prototyping.

Technical Context

The LM5149-Q1EVM-400 implements a peak current-mode controlled synchronous buck topology using the LM5149-Q1 controller in a 24-pin VQFN (5.5 mm × 3.5 mm) package. It integrates high-current gate drivers (2.2 A source / 3.2 A sink), adaptive dead-time control (13 ns), and internal slope compensation synchronized to switching frequency.

This EVM supports forced PWM (FPWM) or pulsed-frequency modulation (PFM) operation, includes a 180° phase-shifted SYNCOUT signal for multi-phase expansion, and uses AEC-Q200-rated passive components-including 1 µH buck inductor, 4×4.7 µF/100 V input capacitors, and 22 µF/25 V output capacitors-on an 83 mm × 43 mm PCB with optimized thermal copper layers.

Key Specifications

Availability

LM5149-Q1EVM-400 is available at Aetrix Electronics and suitable for automotive HEV/EV powertrain development, ADAS sensor fusion modules, and instrument cluster power supply validation requiring stable component supply, pre-validated thermal performance, and production-representative EMI behavior.

Supply support for LM5149-Q1EVM-400 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for automotive, industrial, and personal electronics markets.

The LM5149-Q1EVM-400 belongs to TI's automotive synchronous buck controller evaluation platform family, designed specifically to accelerate functional-safety-compliant DC/DC design for AEC-Q100 Grade 1 applications operating up to 150°C junction temperature.

FAQ

What is the primary function of the LM5149-Q1EVM-400?

The LM5149-Q1EVM-400 is a ready-to-use evaluation module that demonstrates the LM5149-Q1 synchronous buck controller in a production-intent automotive power supply. It converts 15–72 V input to a tightly regulated 12 V/8 A output, featuring DRSS, active EMI filtering, and FPWM/PFM mode selection. Engineers use the LM5149-Q1EVM-400 to validate loop stability, thermal behavior, and EMI performance before finalizing their own LM5149-Q1-based designs.

Does the LM5149-Q1EVM-400 support adjustable output voltages?

Yes, the LM5149-Q1EVM-400 defaults to 12 V but supports adjustment down to 0.8 V via feedback resistor changes (RFB and R23 in schematic). The user guide confirms configurable outputs of 5 V, 3.3 V, or custom values using the onboard FB node and external resistor network. This flexibility allows the LM5149-Q1EVM-400 to emulate multiple downstream rails during system-level testing.

How is EMI performance validated on the LM5149-Q1EVM-400?

The LM5149-Q1EVM-400 is validated per CISPR 25 Class 5 conducted emissions standards (150 kHz–30 MHz) using a 5-µH LISN, with DRSS and active EMI filtering enabled. Figure 6-13 in the User's Guide shows measured peak and average spectra staying below Class 5 limits. The LM5149-Q1EVM-400 achieves this with no external shielding or ferrite beads-relying solely on the LM5149-Q1's integrated AEF architecture and optimized PCB layout.

What thermal performance can be expected from the LM5149-Q1EVM-400 at full load?

At VIN = 48 V, IOUT = 8 A, and Tamb = 25°C with no airflow, the LM5149-Q1EVM-400 achieves thermal equilibrium with the LM5149-Q1 junction temperature ≤125°C (well below its 150°C rating), as shown in Figure 6-14. The 6-layer PCB uses internal copper planes and thermal vias under the controller and MOSFETs to dissipate heat-enabling the LM5149-Q1EVM-400 to sustain full load without forced cooling in most automotive under-hood environments.

Can the LM5149-Q1EVM-400 be synchronized to an external clock?

Yes, the LM5149-Q1EVM-400 supports external synchronization via the PFM/SYNC pin. Its nominal 400 kHz switching frequency can be adjusted ±20% using an external clock signal, and it provides a 180° phase-shifted SYNCOUT signal for dual-phase leader-follower configurations. This capability is documented in Section 1.2 and Table 2-1 of the LM5149-Q1EVM-400 User's Guide and is accessible through J2 pin 18 on the board.