Texas Instruments LM3423BS2LYEV/NOPB

Overview

LM3423BS2LYEV/NOPB from Texas Instruments is an evaluation board designed to demonstrate the LM3423 high-voltage, low-side N-FET controller in buck-boost configuration for constant-current driving of high-power LED strings. It supports 4.5V–35V input, delivers up to 1A LED current at up to 35V output, operates at 600 kHz switching frequency, and implements high-side current sensing with programmable OVP (56V), UVLO (8.4V), and fast PWM dimming-targeting automotive lighting and industrial LED signage.

For engineers reviewing the LM3423BS2LYEV/NOPB datasheet, LM3423BS2LYEV/NOPB pinout, LM3423BS2LYEV/NOPB application, or LM3423BS2LYEV/NOPB equivalent, this evaluation board provides verified reference design implementation of peak current-mode buck-boost LED regulation-including jumper-configurable current sensing (R_DS(ON) or external sense resistor), dual-mode PWM dimming (high-side/low-side), fault flag monitoring, and full thermal and overvoltage protection validation.

Technical Context

The LM3423BS2LYEV/NOPB implements a complete, two-layer FR4 evaluation platform for the LM3423 controller IC, featuring banana-plug power and LED connections (VIN, GND, LED+, LED−), on-board jumpers for EN, IS, DIM, FLT, and RPD configuration, and test points for all critical signals including HSP/HSN, CSH, COMP, GATE, FLT, TIMR, and L-RDY. It validates the LM3423's 4.5V–75V input capability (configured for 4.5V–35V out-of-box), 2 MHz max switching frequency, and peak current-mode control loop stability with transconductance error amplifier compensation.

This board demonstrates the LM3423's integrated high-side current sense amplifier (HSP/HSN inputs), adjustable current sense voltage via CSH pin (1.24 V reference), programmable fault timer (via TIMR pin and external capacitor), and "zero-current" shutdown mode (RPD pin tied to bottom resistors of UVLO/OVP dividers). All features are user-accessible through documented jumper settings and component population options per TI AN-1907.

Key Specifications

Availability

LM3423BS2LYEV/NOPB is available at Aetrix Electronics and suitable for automotive headlamp development, industrial LED signage prototyping, and high-brightness display backlight evaluation requiring stable component supply, traceable sourcing, and long-term design support.

Supply support for LM3423BS2LYEV/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 decades of leadership in LED driver innovation and precision power control ICs.

The LM3423 product line is designed specifically for high-efficiency, high-voltage constant-current LED regulation in buck, boost, and buck-boost topologies - targeting applications demanding robust thermal performance, fast PWM dimming, and flexible protection schemes.

FAQ

What is the primary function of the LM3423BS2LYEV/NOPB evaluation board?

The LM3423BS2LYEV/NOPB evaluation board is a fully assembled, tested platform for validating the LM3423 high-voltage, low-side N-FET LED controller in buck-boost topology. It enables rapid prototyping of constant-current LED drivers with configurable current sensing, dimming, protection, and compensation - directly supporting design-in of the LM3423 IC in real-world lighting systems.

Does the LM3423BS2LYEV/NOPB support input voltages above 35 V?

Yes - while configured for 4.5 V–35 V operation out-of-box, the LM3423BS2LYEV/NOPB can be modified to support up to 75 V input and output by upgrading input/output capacitors (C1/C8/C17/C4/C7/C11/C16) and power MOSFETs (Q4/Q5/Q7) to higher-voltage ratings, as specified in TI AN-1907 Section 2. The LM3423 IC itself supports 4.5 V–75 V operation.

How is LED current set and adjusted on the LM3423BS2LYEV/NOPB?

LED current is set using high-side sensing via HSP/HSN pins and regulated through the CSH pin (1.24 V reference). On the LM3423BS2LYEV/NOPB, fixed 1 A current is achieved with R9 = 0.1 Ω, R7 = 1 kΩ, and R17 = 12.4 kΩ. Users adjust I_LED by changing R9 or the R7/R17 ratio - equations and design guidance are provided in TI AN-1907 Sections 5.1–5.2.

Can the LM3423BS2LYEV/NOPB be used for both high-side and low-side PWM dimming?

Yes - the LM3423BS2LYEV/NOPB supports both configurations. High-side dimming is enabled by closing jumper J5; low-side dimming is enabled by opening J5 (default setting). The board includes dedicated MOSFET Q7 and drive circuitry for either mode, and the PWM signal is applied via BNC connector or TP6 test point per TI AN-1907 Section 5.5.

What protection features are implemented and how are they configured on the LM3423BS2LYEV/NOPB?

The LM3423BS2LYEV/NOPB implements overvoltage protection (OVP, 56 V default), under-voltage lockout (UVLO, 8.4 V), cycle-by-cycle current limiting, thermal shutdown, and fault flag assertion (FLT pin). OVP is set via R20/R22; UVLO uses R13/R25 on nDIM; fault timing is controlled via TIMR pin and external capacitor (J6 open); all are jumper- or resistor-configurable per TI AN-1907 Sections 5.4, 5.10, and 5.11.