Texas Instruments TLC5958RTQT

Overview

TLC5958RTQT from Texas Instruments is a 48-channel, 16-bit enhanced-spectrum PWM LED driver with integrated 48K-bit display memory, pre-charge FET, and LED open detection (LOD). It delivers constant-current sink outputs up to 25 mA per channel at 5 V_CC, supports 32-multiplexing, and operates across –40°C to +85°C for high-density video displays and signage.

For engineers reviewing the TLC5958RTQT datasheet, TLC5958RTQT pinout, TLC5958RTQT application, or TLC5958RTQT equivalent, key selection criteria include its 16-bit grayscale resolution, 3-bit global + 9-bit per-color brightness control, thermal shutdown (170°C), IREF resistor short protection, and daisy-chainable serial interface with 25 MHz SCLK and 33 MHz GCLK.

Technical Context

The TLC5958RTQT implements an ES-PWM architecture with dual 48K-bit SRAM banks (A/B) enabling seamless frame buffering for flicker-free 32-line multiplexed LED scanning. Its 48 output channels are grouped into three 16-channel color banks (R/G/B), each independently adjustable via 9-bit color brightness control (CC) and collectively scaled by 3-bit global brightness control (BC).

It features a dedicated grayscale clock (GCLK) input that drives internal 16-bit counters for precise PWM timing, LAT-controlled data latching, and SIN/SCLK/SOUT serial interface supporting daisy-chaining. Built-in LOD flag reporting, thermal shutdown (TSD), and power-save mode (0.8 mA typ) support robust operation in high-reliability LED systems.

Key Specifications

Pinout & Package

VQFN-56 package (8.0 mm × 8.0 mm) with exposed thermal pad soldered to PCB ground for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5958RTQT, TLC5947RTQT offers lower integration and no multiplex capability, while IS31FL3733-QFLS4 provides comparable channel count and memory but omits key reliability features like LOD and pre-charge FET-making TLC5958RTQT optimal for mission-critical, high-refresh LED systems.

Availability

TLC5958RTQT is available at Aetrix Electronics and suitable for LED video walls, outdoor signage, stage lighting, and medical imaging displays requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for TLC5958RTQT 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 ICs for industrial, automotive, and consumer applications.

The TLC5958RTQT belongs to TI's high-performance LED driver product line, engineered specifically for high-refresh, high-density multiplexed LED displays demanding precision grayscale, thermal resilience, and system-level diagnostics.

FAQ

What is the maximum LED supply voltage supported by the TLC5958RTQT?

The TLC5958RTQT supports LED anode voltages up to 10 V, enabling direct drive of high-forward-voltage blue and white LEDs without external boost circuitry. This rating is specified in the Absolute Maximum Ratings table (V_OUT = –0.3 V to 11 V), and the device maintains constant-current regulation across this range when configured with appropriate IREF resistance and BC/CC settings. The TLC5958RTQT achieves this using robust output transistor design and thermal management via its exposed thermal pad.

How does the TLC5958RTQT implement LED open detection (LOD)?

The TLC5958RTQT integrates a per-channel LOD circuit that monitors output voltage during active sinking. When an open LED causes the output voltage to exceed a programmable threshold (V_LOD0–V_LOD3, selectable via FC2 register), the device sets a single LOD flag bit accessible through the serial interface. This flag reflects the logical OR of all 48 channels' open conditions-enabling fast system-level fault detection without polling each channel individually. The TLC5958RTQT does not report which specific channel is open, only that at least one is open.

Can the TLC5958RTQT be used in daisy-chain configurations, and what are the timing constraints?

Yes, the TLC5958RTQT supports seamless daisy-chaining via its SIN and SOUT pins. Data written to the first device's SIN propagates through SOUT to the next device's SIN on each SCLK rising edge. The maximum SCLK frequency remains 25 MHz regardless of chain length, but cumulative propagation delay requires careful PCB layout-especially for chains exceeding 5 devices. Latency between LAT pulse and effective GS update increases linearly with chain length, so frame synchronization must account for worst-case delay across all devices in the chain. The TLC5958RTQT's internal architecture ensures deterministic behavior under these conditions.

What is the role of the pre-charge FET in the TLC5958RTQT, and how does it prevent ghosting?

The pre-charge FET in the TLC5958RTQT briefly activates before the main current sink turns on during multiplexed scanning. This pre-charges the LED capacitance and parasitic wiring capacitance to near the LED forward voltage, eliminating the transient delay that causes faint "ghost" images on adjacent lines. The FET is synchronized to the line-enable timing and controlled internally-no external signals or configuration are required. This feature is especially critical in high-speed, high-density LED panels where ghosting would otherwise degrade image clarity. The TLC5958RTQT implements this function transparently as part of its multiplex timing engine.

How does the dual-bank 48K-bit memory improve display performance in the TLC5958RTQT?

The TLC5958RTQT's dual 48K-bit SRAM banks (A and B) enable concurrent display and update operations: while Bank A drives the current frame, Bank B accepts new grayscale data for the next frame via the serial interface. This eliminates visible tearing or stutter during rapid content changes and supports true 32-line multiplexing without host CPU bottlenecks. Each bank stores 16-bit data for all 48 channels across 32 lines (48 × 16 × 32 = 48K bits). The VSYNC command swaps active banks atomically-ensuring glitch-free transitions. This architecture is fundamental to the TLC5958RTQT's ability to sustain high visual refresh rates in professional LED displays.