Texas Instruments TLC5971RGET

Overview

TLC5971RGET from Texas Instruments is a 12-channel, 16-bit PWM RGB LED driver with integrated 3.3-V linear regulator, constant-current sink outputs (60 mA per channel), enhanced spectrum grayscale control (65536 steps), and global brightness control (128 steps per color group). It supports cascading for large LED arrays in architectural lighting and stage displays.

For engineers reviewing the TLC5971RGET datasheet, TLC5971RGET pinout, TLC5971RGET application, or TLC5971RGET equivalent, key selection criteria include its 20-pin HTSSOP package, VCC range (6–17 V with internal regulator), IREF-based current programming, two-wire serial interface (SDTI/SCKI), thermal shutdown with auto-restart, and RGB channel grouping for independent brightness tuning.

Technical Context

The TLC5971RGET implements a 224-bit shift register with dedicated GS data (16 bits × 12 channels = 192 bits), BC data (7 bits × 3 groups = 21 bits), and control bits (11 bits). Its internal oscillator (6–12 MHz) or external clock drives PWM timing, while the 3.3-V VREG output powers external logic or daisy-chained devices.

Each of the 12 outputs (OUTR0–OUTR3, OUTG0–OUTG3, OUTB0–OUTB3) operates as an independently programmable constant-current sink with ±1% channel-to-channel accuracy and up to 17-V LED supply capability. The device features auto-display repeat, display timing reset, and unlimited cascading via SDTO/SCKO forwarding.

Key Specifications

Pinout & Package

Package: 20-pin HTSSOP (6.50 mm × 4.40 mm) with exposed PowerPAD for thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5947RGE and IS31FL3731-QFLS4-TR, the TLC5971RGET uniquely combines 16-bit grayscale, integrated 3.3-V regulation, and seamless daisy-chaining-making it optimal for scalable RGB strip systems requiring high-fidelity color control and minimal BOM count.

Availability

TLC5971RGET is available at Aetrix Electronics and suitable for architectural lighting, stage displays, and RGB video walls requiring stable component supply, long-term production continuity, and thermal reliability in ambient temperatures from –40°C to +85°C.

Supply support for TLC5971RGET 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 digital signal technologies with broad industrial and automotive design expertise.

The TLC5971 product line delivers high-precision, thermally robust LED drivers for professional lighting systems, emphasizing grayscale fidelity, cascading scalability, and integrated power management for reduced system complexity.

FAQ

What is the maximum LED supply voltage supported by the TLC5971RGET?

The TLC5971RGET supports LED supply voltages up to 17 V on its OUTR0–OUTB3 pins. This allows driving longer series strings of RGB LEDs-e.g., four 3-V blue LEDs (12 V total) plus margin-while maintaining 60 mA sink capability. The device's output voltage compliance is independent of VCC, which can be 6–17 V when using the internal regulator or 3–5.5 V when bypassing it.

How does the IREF pin set output current in the TLC5971RGET?

The IREF pin on the TLC5971RGET accepts an external resistor to GND that directly programs the maximum sink current for all 12 channels. For example, a 0.82-kΩ resistor yields 60 mA per channel (±1% typical accuracy); a 24-kΩ resistor sets 2 mA. The relationship is inverse and linear: I_OUTMAX ≈ 1.21 V / R_IREF. Connecting IREF directly to GND forces all outputs off-a hardware blanking feature.

Can the TLC5971RGET operate without its internal linear regulator?

Yes, the TLC5971RGET can operate without using its internal linear regulator by supplying 3–5.5 V directly to the VREG pin while tying VCC to the same rail or leaving it unconnected. In this mode, the internal regulator is disabled, reducing power dissipation and enabling use in low-voltage systems. The VREG pin then functions solely as a 3.3-V output for external logic, with up to 25 mA sink capability.

What is the purpose of the SDTO and SCKO pins on the TLC5971RGET?

The SDTO (serial data output) and SCKO (serial clock output) pins on the TLC5971RGET enable daisy-chaining multiple devices. SDTO forwards the MSB of the internal 224-bit shift register, while SCKO retimes the input SCKI clock to align with SDTO's data edge. This eliminates cumulative timing skew across long chains, supporting unlimited cascading for large-scale LED installations without signal integrity degradation.

Does the TLC5971RGET support both internal and external PWM clock sources?

Yes, the TLC5971RGET supports selectable PWM clock sources via the EXTGCK bit in its configuration register. When EXTGCK = 0, the internal oscillator (6–12 MHz) generates the grayscale clock; when EXTGCK = 1, the SCKI input serves as the PWM clock source. This flexibility allows synchronization to external timing masters or optimization of PWM frequency for EMI reduction in sensitive environments.