Texas Instruments TLC5929DBQR

Overview

TLC5929DBQR from Texas Instruments is a 16-channel constant-current LED sink driver with 7-bit global brightness control (128 steps), ±1% typical channel-to-channel current accuracy, and integrated LED open/short detection. It operates from 3.0 V to 5.5 V supply voltage, supports up to 10 V LED supply, and delivers up to 50 mA per channel at VCC > 3.6 V - used in variable message signs and high-reliability LED illumination systems.

For engineers reviewing the TLC5929DBQR datasheet, TLC5929DBQR pinout, TLC5929DBQR application, or TLC5929DBQR equivalent, key selection criteria include its daisy-chainable serial interface (33 MHz SCLK), invisible detection mode for fault diagnosis during output-off states, power-save mode (10 µA ICC), and thermal shutdown with pre-warning flag at 138°C junction temperature.

Technical Context

The TLC5929DBQR implements a 17-bit serial shift register with dual-latch architecture: LSB–bit15 load into output on/off data latch on LAT rising edge when MSB = 0; bit0–bit15 load into control data latch (global BC, LSD voltage select, IDM timing) when MSB = 1. All 16 outputs are independently controllable constant-current sinks referenced to a single external IREF resistor.

Error diagnostics include LED open detection (LOD) threshold at 0.30 V, four programmable LED short detection (LSD) thresholds (0.35×VCC to 0.65×VCC), output leakage detection (OLD) at 3 µA, and thermal flags (PTW at 138°C, TEF at 150°C). BLANK pulse width minimum is 40 ns, and propagation delay from LAT to output state change is 35 ns.

Key Specifications

Pinout & Package

SSOP-24 (DBQ) package with exposed thermal pad (PowerPAD™ not present in DBQ variant); 0.635 mm pitch, 8.2 mm × 3.91 mm body size; RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5929DBQR, TLC5940RHBR offers finer per-channel intensity control but requires external fault management, while MAX7219CWG+ provides compact digit driving at the cost of current regulation fidelity and diagnostic capability - TLC5929DBQR remains optimal for standalone, fault-aware, high-current LED arrays.

Availability

TLC5929DBQR is available at Aetrix Electronics and suitable for variable message signs, architectural illumination systems, and industrial panel displays requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TLC5929DBQR 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and industrial-grade performance.

The TLC5929 belongs to TI's high-integrity LED driver product line, engineered specifically for outdoor signage and mission-critical illumination where autonomous fault detection, thermal resilience, and current-matching uniformity are mandatory.

FAQ

What is the maximum LED supply voltage supported by the TLC5929DBQR?

The TLC5929DBQR supports LED anode supply voltages up to 10 V, independent of its VCC logic supply (3.0 V to 5.5 V). This allows direct connection to common 5 V, 9 V, or 12 V LED rails without level-shifting. The OUT0–OUT15 pins are rated for –0.3 V to +11 V, providing 1 V margin above the 10 V maximum. This capability is essential for driving high-VF LED strings in signage applications.

How does the invisible detection mode (IDM) function in the TLC5929DBQR?

The invisible detection mode (IDM) in the TLC5929DBQR enables LED open detection (LOD) and LED short detection (LSD) even when all outputs are turned OFF via BLANK or latch data. IDM operates using brief, internally timed test pulses that do not activate visible LED emission. Detection results are stored in status registers and readable via SOUT - allowing continuous health monitoring without disrupting display operation or causing flicker in the TLC5929DBQR.

Can the TLC5929DBQR be daisy-chained, and what is the maximum number of devices?

Yes, the TLC5929DBQR supports daisy-chaining via its SIN/SOUT interface: SOUT of one device connects to SIN of the next, sharing a common SCLK and LAT. There is no hard limit on chain length, but practical constraints include SCLK timing margin (33 MHz max), cumulative propagation delay (<11 ns per stage), and total shift register bits (17 × N). For reliable operation at full speed, chains exceeding 10 devices require careful PCB layout and termination - confirmed in TI's SBVS159B datasheet for the TLC5929DBQR.

What is the role of the IREF pin, and how is output current calculated for the TLC5929DBQR?

The IREF pin on the TLC5929DBQR sets the maximum sink current (IOLCMax) for all 16 channels via an external resistor (RIREF) to GND. Internal circuitry generates a 1.205 V reference at IREF, so IOLCMax ≈ (1.205 V × 54.8) / RIREF. For example, RIREF = 1.32 kΩ yields ~50 mA (VCC > 3.6 V). Current per channel is then scaled by the 7-bit global brightness control (BC) value: IOLCn = IOLCMax × BC/127 - a core operating principle of the TLC5929DBQR.

Does the TLC5929DBQR include thermal protection, and what are the trip thresholds?

Yes, the TLC5929DBQR integrates two thermal safety features: pre-thermal warning (PTW) triggers at 138°C junction temperature, signaling impending thermal stress to the host controller; thermal shutdown (TSD) activates at 150°C to disable outputs and prevent damage. Hysteresis is 10°C, so recovery occurs at 140°C. These thresholds are fixed and unadjustable - part of the die-level protection architecture inherent to the TLC5929DBQR design.