Texas Instruments TLC5902

Overview

TLC5902 from Texas Instruments is a 100-pin HTQFP constant-current LED driver IC with integrated 16-bit shift register, data latch, and pulse-width-controlled 256-gray-scale display capability. It delivers up to 80 mA per channel across 16 outputs or 120 mA across 8 paired outputs, with ±4% current matching accuracy and built-in watchdog timer (WDT) and thermal shutdown (TSD) protection - deployed in high-reliability outdoor LED signage and industrial panel displays.

For engineers reviewing the TLC5902 datasheet, TLC5902 pinout, TLC5902 application, or TLC5902 equivalent, key selection criteria include its dual-mode output configuration (80 mA × 16 or 120 mA × 8), external resistor–set current precision, 256-step gray scale via GSCLK synchronization, brightness deviation compensation across LEDs, and open-collector DOWN fault indicator for system-level thermal/WDT monitoring.

Technical Context

The TLC5902 implements a dual-path serial interface: one 16×8-bit (or 8×8-bit) shift register/latch for gray-scale data and a separate 1×8-bit latch for brightness control, both sharing DIN0–DIN7 and controlled by RSEL, LATCH, and DCLK. Its constant-current sink architecture uses an external IREF resistor to set base current, with 38× scaling and ±4% inter-channel matching at V_OUT ≤ 0.7 V (40–80 mA range).

Operation supports two modes via MODE pin: 16-bit mode enables independent 80 mA sinks on OUT0–OUT15; 8-bit mode pairs outputs (e.g., OUT0/OUT1) for 120 mA total per pair, requiring external wiring. Protection includes WDT (capacitor-adjustable timeout, ~3 ms default) and TSD (trip at 150–170°C), both asserting open-drain DOWN while preserving logic functionality.

Key Specifications

Pinout & Package

Package: 100-pin HTQFP (PZ package), thermally enhanced with exposed conductive pad soldered to PCB ground plane for thermal management and noise reduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant-current LED driver applications.

Compared with TLC5902, TLC5928 offers higher per-channel drive but removes critical safety features, while MAX6967 trades PWM fidelity and current capability for integration density and bus simplicity - making TLC5902 optimal for outdoor/industrial displays demanding robustness, precision, and scalable gray scale.

Availability

TLC5902 is available at Aetrix Electronics and suitable for outdoor LED signage, industrial control panels, stage lighting systems, and medical equipment displays requiring stable component supply across extended production lifecycles.

Supply support for TLC5902 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 high-reliability power management solutions.

The TLC5902 belongs to TI's legacy LED driver portfolio designed for high-channel-count, high-precision LED video and signage applications requiring integrated gray-scale control, thermal resilience, and system-level fault signaling.

FAQ

What output configurations does the TLC5902 support?

The TLC5902 supports two hardware-configurable output modes via the MODE pin: 16 independent 80 mA constant-current sinks (MODE = high), or 8 paired outputs delivering 120 mA total per pair (MODE = low). In 8-bit mode, outputs like OUT0 and OUT1 must be externally wired together, and current is set accordingly using the IREF resistor. This flexibility allows optimization for either pixel density or per-pixel brightness in LED matrix designs.

How does the TLC5902 achieve 256-step gray scale control?

The TLC5902 achieves 256-step gray scale using an internal 8-bit counter synchronized to the GSCLK input. Each output remains active (sinking current) until the counter matches the 8-bit gray-scale value latched for that channel. The GSCLK frequency determines frame rate - e.g., at 4 MHz, full 256-step refresh occurs every 64 µs - enabling smooth, flicker-free LED intensity modulation essential for video-grade displays.

Can the TLC5902 compensate for LED brightness variation across multiple ICs?

Yes, the TLC5902 includes dedicated 5-bit brightness control latch circuitry allowing 32-step (≈1.6% increments) adjustment of output current per IC. This lets designers correct inter-device LED intensity mismatches after PCB assembly by loading custom values via the DIN/RSEL interface - eliminating manual resistor trimming and improving yield in large-panel manufacturing.

What protection functions are built into the TLC5902?

The TLC5902 integrates two independent hardware protection circuits: a watchdog timer (WDT) that disables outputs if the scan signal stalls (configurable via WD_CAP capacitor), and thermal shutdown (TSD) that activates above 150–170°C junction temperature (enabled via TS_ENA pin). Both assert the open-drain DOWN pin, enabling system-level fault detection without software intervention - critical for unattended outdoor signage.

What is the role of the IREF pin on the TLC5902?

The IREF pin sets the base current for all 16 constant-current outputs using a single external resistor connected to GND. The internal circuit applies 38× scaling: for example, a 590 Ω resistor yields ≈80 mA per channel in 16-bit mode. Current accuracy is ±4% between channels, and the voltage at IREF is regulated to 1.24 V, ensuring stable operation across supply and temperature variations - simplifying BOM and layout versus per-channel current-setting components.