Texas Instruments TLC5928DBQR

Overview

TLC5928DBQR from Texas Instruments is a 16-channel constant-current LED sink driver with LED open detection (LOD) and pre-thermal warning (PTW). It delivers up to 35 mA per channel, supports 35-MHz serial data transfer, operates from 3.0 V to 5.5 V supply, and features 20-ns BLANK pulse width - used in high-reliability LED video displays requiring real-time fault monitoring.

For engineers reviewing the TLC5928DBQR datasheet, TLC5928DBQR pinout, TLC5928DBQR application, or TLC5928DBQR equivalent, key selection criteria include constant-current accuracy (±1% channel-to-channel), daisy-chain capability via SIN/SOUT, LOD/PTW error readback timing, and SSOP-24 thermal performance under sustained LED load conditions.

Technical Context

The TLC5928DBQR implements a 16-bit serial shift register followed by a parallel latch for on/off control of all 16 constant-current sinks. Each output's current is set by a single external resistor (RIREF) tied between IREF and GND, generating a nominal 1.20-V reference voltage.

Two dedicated error-detection circuits operate independently: LOD monitors each active OUTn voltage against a 0.30-V threshold to flag open or GND-shorted LEDs, while PTW triggers at +138 °C junction temperature. Error status is latched on BLANK rising edge and shifted out via SOUT synchronized to SCLK.

Key Specifications

Pinout & Package

Package: SSOP-24 (DBQ), 5.3 mm × 7.2 mm body, 0.65 mm pitch, exposed thermal pad (not internally connected to GND - must be externally soldered to PCB ground plane).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED sink driver applications.

Compared with TLC5928DBQR, TLC5940PWPR offers superior grayscale fidelity but requires external fault handling, while MAX7219CWG+ simplifies 8-channel designs at the expense of LOD/PTW and 16-channel scalability.

Availability

TLC5928DBQR is available at Aetrix Electronics and suitable for LED video displays, message boards, illumination systems, and industrial control panels requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for TLC5928DBQR 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 ICs, with decades of experience in high-reliability LED driver design.

The TLC5928 product line targets industrial and commercial LED display systems requiring integrated fault diagnostics, daisy-chain scalability, and robust constant-current regulation - not just basic LED switching.

FAQ

What is the maximum LED supply voltage supported by the TLC5928DBQR?

The TLC5928DBQR supports LED anode supply voltages up to 17 V at its OUT0–OUT15 pins. This allows direct driving of multi-LED series strings without external high-voltage transistors, provided the VCC supply remains within 3.0 V to 5.5 V. The 17-V rating is absolute maximum - design margin should be applied based on worst-case forward voltage and temperature drift.

How does the TLC5928DBQR implement LED open detection (LOD)?

The TLC5928DBQR monitors the voltage at each active OUTn pin during current-sink operation. If VOUTn ≤ 0.30 V (typical), the corresponding LOD bit is set to '1' in the Status Information Data (SID) register. This condition indicates either an open-circuit LED or one shorted to GND. The LOD status is latched on the rising edge of BLANK and readable via SOUT after LAT synchronization - the TLC5928DBQR requires ≥1 ms on-time for valid LOD sampling.

Can multiple TLC5928DBQR devices be daisy-chained, and how is data routed?

Yes, multiple TLC5928DBQR devices can be daisy-chained using SIN and SOUT pins. Serial data enters the first device's SIN pin, shifts through its 16-bit register, and exits SOUT to the next device's SIN. After loading all devices, a single LAT pulse transfers the full chain's data to their output latches simultaneously. This architecture reduces MCU GPIO count and ensures synchronized update across large LED arrays driven by TLC5928DBQR.

What is the role of the IREF pin on the TLC5928DBQR, and how is current set?

The IREF pin on the TLC5928DBQR provides a 1.20-V internal reference voltage. Connecting an external resistor (RIREF) between IREF and GND sets the full-scale sink current for all 16 channels using IOUT = 42 × (1.20 V / RIREF). For example, a 1.44-kΩ resistor yields ~35 mA. The TLC5928DBQR supports 2–35 mA range; RIREF values from 25.2 kΩ to 1.44 kΩ are valid per datasheet Table 1.

Does the TLC5928DBQR require external pull-up or pull-down resistors on its control pins?

No, the TLC5928DBQR does not require external pull-up or pull-down resistors on SIN, SCLK, LAT, or BLANK. These inputs feature Schmitt-triggered CMOS logic with defined VIH (≥0.7×VCC) and VIL (≤0.3×VCC) thresholds. However, BLANK must be held high during power-up to prevent unintended output activation due to random latch states - this is a functional requirement, not a biasing one. The TLC5928DBQR's internal design ensures clean signal interpretation without external passive components.