Texas Instruments LM3481-FLYBACKEVM

Overview

LM3481-FLYBACKEVM from Texas Instruments is an evaluation module designed to validate isolated flyback converter operation using the LM3481 low-side N-channel controller. It supports 5 V to 32 V input, delivers 12 V at up to 2 A output, operates at a nominal 130 kHz switching frequency, and enables loop-response characterization via Loop_1/Loop_2 test points.

For engineers reviewing the LM3481-FLYBACKEVM datasheet, LM3481-FLYBACKEVM pinout, LM3481-FLYBACKEVM application, or LM3481-FLYBACKEVM equivalent, this EVM provides measured efficiency curves, load transient waveforms, output ripple data, SW node overshoot analysis, and gain/phase plots across multiple input voltages (12 V, 20 V, 28 V) under full-load conditions.

Technical Context

The LM3481-FLYBACKEVM implements a current-mode controlled isolated flyback topology with an LM3481MM/NOPB controller, CSD19502Q5B MOSFET, LTV-817S optocoupler feedback path, and TL431AIDBZR shunt regulator. It uses a custom Wurth 12 µH EFD25 transformer with 1:1 primary-to-secondary turns ratio and supports external loop compensation via R8 replacement for stability analysis.

Test points SW, ISEN, D_SW, Loop_1, Loop_2, Vin, Vout, TP_GND, and ISOGND provide direct access to critical nodes for oscilloscope measurement of switch-node voltage, primary current sense, secondary rectifier behavior, and control-loop gain/phase response - all validated at 25°C ambient with input voltages from 5 V to 32 V and load currents up to 2 A.

Key Specifications

Availability

LM3481-FLYBACKEVM is available at Aetrix Electronics and suitable for power supply validation, flyback topology benchmarking, and control-loop stability assessment requiring stable component supply, traceable sourcing, and documented test data.

Supply support for LM3481-FLYBACKEVM 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 specializing in analog, embedded processing, and power management technologies, with decades of leadership in power conversion ICs and evaluation platforms.

The LM3481-FLYBACKEVM belongs to TI's power management evaluation module family, developed specifically to accelerate design-in of LM3481-based isolated DC/DC converters by providing fully assembled, characterized, and documented reference hardware.

FAQ

What is the primary function of the LM3481-FLYBACKEVM?

The LM3481-FLYBACKEVM is an evaluation module that demonstrates and validates the performance of the LM3481 controller in an isolated flyback configuration. It enables engineers to measure real-world parameters including efficiency, load transient response, output ripple, loop stability, and switch-node behavior - all using the exact LM3481MM/NOPB controller and supporting components specified in the official SNVU528 User's Guide. The LM3481-FLYBACKEVM is not a production-ready power supply but a lab-grade tool for topology verification and design refinement.

Which controller IC is used on the LM3481-FLYBACKEVM board?

The LM3481-FLYBACKEVM uses the LM3481MM/NOPB - a 10-pin MSOP packaged, low-side N-channel PWM controller optimized for boost, SEPIC, and flyback topologies. This device features current-mode control, programmable switching frequency (100 kHz–1 MHz), cycle-by-cycle current limiting, and adjustable UVLO. Its presence on the LM3481-FLYBACKEVM is confirmed in the Bill of Materials (Item 41) and schematic (U1), and it drives the CSD19502Q5B MOSFET in the primary switch leg.

Does the LM3481-FLYBACKEVM support loop stability analysis?

Yes, the LM3481-FLYBACKEVM explicitly supports control-loop stability analysis via dedicated test points Loop_1 and Loop_2. As documented in Section 4.2 and Figure 6 of SNVU528, users replace R8 with a 49.9-Ω resistor and inject an AC signal across it to perform gain/phase measurements. Measured Bode plots are provided for 12 V and 20 V input conditions at 2 A load, enabling direct validation of compensation network design before final PCB layout.

What input and output connectors are provided on the LM3481-FLYBACKEVM?

The LM3481-FLYBACKEVM features four standard 5.5 mm banana jacks: J1 (VIN, positive input), J2 (GND, input return), J3 (VOUT, positive output), and J4 (ISO GND, isolated output return). These connectors allow safe, low-inductance connection to bench power supplies and electronic loads. Input voltage sensing (Vin, TP_GND) and output voltage sensing (Vout, ISOGND) are also accessible via separate test points to minimize measurement error from connector resistance.

Can the LM3481-FLYBACKEVM be used for production applications?

No, the LM3481-FLYBACKEVM is strictly intended for evaluation and development use per TI's Standard Terms and Conditions for Evaluation Modules. It is not certified for safety, EMC, or regulatory compliance in end equipment; lacks conformal coating, enclosure, or production-grade thermal management; and contains components (e.g., non-automotive-grade capacitors, unshielded transformer) unsuitable for deployment. TI explicitly prohibits assembly of the LM3481-FLYBACKEVM into finished products - its role is limited to feasibility testing, parameter validation, and schematic/layout reference during design phase.