Texas Instruments LM5020EVAL/NOPB

Overview

LM5020EVAL/NOPB from Texas Instruments is a fully assembled, two-layer evaluation board implementing a non-isolated flyback DC-DC converter using the LM5020 PWM controller, delivering 3.3 V at up to 4.5 A from a 30–75 V input. It features measured efficiency of 85% at 1.5 A, <0.1% line regulation, and 1.5% load regulation - validated for continuous operation below 40°C with convection cooling.

For engineers reviewing the LM5020EVAL/NOPB datasheet, LM5020EVAL/NOPB application, LM5020EVAL/NOPB setup, or LM5020EVAL/NOPB performance validation, this board enables rapid functional verification of LM5020-based flyback designs, including gate drive timing, soft-start behavior, load-step response, and transformer waveform analysis under real operating conditions.

Technical Context

The LM5020EVAL/NOPB implements a primary-side regulated, current-mode controlled non-isolated flyback topology. It uses the LM5020 VSSOP-10 controller with internal start-up regulator, soft-start, UVLO (30 V turn-on, 25 V turn-off), and cycle-by-cycle current limiting - all configured for fixed-frequency operation via external RT resistor.

Power stage components include Si7898DP N-channel MOSFET (150 V, 85 mΩ), MBRD835L Schottky output rectifier (8 A, 35 V), and Coilcraft B0695-A or Pulse PA0751 EFD20 flyback transformer. Input filtering uses dual 2.2 µF/100 V X7R ceramics; output employs 270 µF aluminum + dual 100 µF X7S ceramics for low-impedance 3.3 V delivery.

Key Specifications

Availability

LM5020EVAL/NOPB is available at Aetrix Electronics and suitable for power supply design validation, flyback topology benchmarking, and LM5020 controller qualification requiring stable component supply, repeatable test setups, and documented performance metrics.

Supply support for LM5020EVAL/NOPB 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 power management technologies, with over 90 years of innovation in high-reliability electronic systems.

The LM5020EVAL/NOPB belongs to TI's Power Management Evaluation Platform family, designed specifically to accelerate development of high-efficiency, wide-input-range DC-DC converters for industrial, telecom, and distributed power applications.

FAQ

What is the purpose of the LM5020EVAL/NOPB evaluation board?

The LM5020EVAL/NOPB evaluation board is a ready-to-use hardware platform that demonstrates and validates the LM5020 PWM controller in a non-isolated flyback configuration. It delivers 3.3 V at up to 4.5 A from 30–75 V input and includes all necessary passive and active components - enabling engineers to verify gate drive waveforms, soft-start behavior, load transient response, and efficiency without designing a custom PCB. The LM5020EVAL/NOPB is not a production-ready power module but a design aid for controller evaluation.

Does the LM5020EVAL/NOPB support isolated flyback topologies?

No, the LM5020EVAL/NOPB implements a non-isolated flyback configuration where input and output share a common ground - as confirmed by its schematic, layout, and application circuit (Figure 12). While the LM5020 controller itself can be used in isolated designs with optocoupler feedback, the LM5020EVAL/NOPB board lacks isolation components (e.g., optocoupler, isolated bias winding) and is explicitly documented for non-isolated operation only.

What input power supply requirements are needed to operate the LM5020EVAL/NOPB?

To fully test the LM5020EVAL/NOPB, a DC power supply capable of delivering ≥75 V and ≥1 A is required, with independent voltage and current limit controls. At 30 V input, input current reaches ~0.63 A; at 75 V, it drops to ~0.23 A. Low-impedance cabling is essential to avoid inrush-induced UVLO chattering - the LM5020EVAL/NOPB's internal UVLO (25 V turn-off) makes it sensitive to supply droop during startup.

How is output voltage regulated on the LM5020EVAL/NOPB?

The LM5020EVAL/NOPB uses primary-side sensing with a resistive divider (R5 = 15.0 kΩ, R6 = 12.4 kΩ) feeding the FB pin of the LM5020 controller, enabling regulation without an optocoupler or secondary-side error amplifier. This configuration achieves 3.3 V ±1% output with 0.1% line regulation and 1.5% load regulation - verified across the full 30–75 V input and 0.23–4.5 A load range per AN-1314 test data.

Can the LM5020EVAL/NOPB be modified for different output voltages or currents?

Yes - the LM5020EVAL/NOPB is intended for design exploration. Output voltage can be adjusted by changing the FB divider (R5/R6); maximum current is limited by MOSFET (Si7898DP), rectifier (MBRD835L), and transformer (B0695-A/PA0751) ratings. However, any modification requires revalidation of thermal performance, stability, and efficiency - the LM5020EVAL/NOPB's documented 4.5 A capability assumes original component selection and layout.