Texas Instruments TLC59731DR

Overview

TLC59731DR from Texas Instruments is a 3-channel, 8-bit PWM LED driver IC with single-wire EasySet™ interface, 50 mA per channel sink current capability, 6 MHz internal GS clock oscillator, and integrated shunt regulator - used for RGB LED cluster lamp displays requiring precise grayscale control and minimal wiring.

For engineers reviewing the TLC59731DR datasheet, TLC59731DR pinout, TLC59731DR application, or TLC59731DR equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative options, and supply support details specific to the SOIC-8 package variant.

Technical Context

The TLC59731DR implements an 8-bit grayscale PWM architecture driven by an internal 6 MHz oscillator, delivering 3.1 kHz display repeat rate with simple gamma correction. Each of its three output channels operates as a constant-current sink with externally set current via per-channel resistors.

It uses a single-wire serial interface (EasySet™) where data encoding relies on measured t_CYCLE between SDI rising edges - enabling unlimited cascading without external clock lines. The device supports two operating modes: no internal shunt regulator (3–5.5 V V_CC) and internal shunt regulator mode (3–6 V V_CC), with OUT terminals rated up to 21 V.

Key Specifications

Pinout & Package

Package: SOIC-8 (4.90 mm × 3.91 mm body size), surface-mount, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL8863T-13 and IS31FL3731-QFLS4-TR, the TLC59731DR uniquely combines single-wire simplicity, per-channel sink control, integrated shunt regulation, and guaranteed 3.1 kHz update rate - making it optimal for cost-sensitive, space-constrained RGB lamp applications where daisy-chain scalability matters.

Availability

TLC59731DR is available at Aetrix Electronics and suitable for architectural LED signage, RGB backlit control panels, and automotive interior mood lighting requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for TLC59731DR 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 company headquartered in Dallas, Texas, designing analog and embedded processing solutions for industrial, automotive, and consumer markets since 1930.

The TLC59731DR belongs to TI's LED driver product line, engineered specifically for low-pin-count, high-efficiency RGB LED control in space-constrained and wiring-sensitive applications - emphasizing ease of integration, thermal robustness, and cascading flexibility.

FAQ

What is the maximum number of TLC59731DR devices that can be cascaded?

The TLC59731DR supports unlimited cascading - there is no hard limit on daisy-chain length. Each device forwards processed SDI data via SDO to the next, with timing automatically adjusted per device using the measured t_CYCLE. Real-world deployments exceed 100 devices without signal degradation when proper termination and trace length guidelines are followed. The TLC59731DR's architecture eliminates clock skew and synchronization overhead inherent in multi-device systems.

Does the TLC59731DR require an external clock source?

No, the TLC59731DR does not require an external clock source. It integrates a 6 MHz internal grayscale (GS) clock oscillator (4–8 MHz typical), which drives all PWM timing functions including the 3.1 kHz display repeat rate. This eliminates the need for crystals, oscillators, or clock distribution networks - simplifying BOM and layout. The TLC59731DR's single-wire EasySet™ interface further removes dependency on synchronous clock lines.

How is LED current set on the TLC59731DR?

LED current on the TLC59731DR is set externally per channel using a resistor (R_Ln) between the OUTn pin and LED cathode. The typical sink current I_OUTn = (V_LED − V_{F_TOTAL} − V_OUTn) / R_Ln, where V_OUTn ≈ 0.6 V at 40 mA. For example, a 12 Ω resistor yields ~42 mA at 5.5 V V_CC. The TLC59731DR itself does not regulate current - it provides precise PWM-controlled conduction time while external resistors define amplitude.

Can the TLC59731DR drive LEDs with forward voltages above 5.5 V?

Yes, the TLC59731DR can drive LEDs with total forward voltages exceeding 5.5 V - its OUT0–OUT2 terminals support up to 21 V. In "no internal shunt regulator" mode (V_CC = 3–5.5 V), the device relies on an external power rail matching the LED string voltage. In "internal shunt regulator" mode (V_CC = 3–6 V), the internal shunt clamps V_CC at ~5.9 V while the OUT pins float up to 21 V relative to GND - enabling direct drive of 6–7 white LEDs in series using a 12 V supply.

What is the purpose of the TEST pin on the TLC59731DR?

The TEST pin on the TLC59731DR is reserved for Texas Instruments internal factory testing and has no defined function in end-user applications. Per the datasheet, it must be left unconnected (open) or tied to GND - driving it high, applying AC signals, or connecting it to other logic may cause undefined behavior or damage. The TLC59731DR operates identically regardless of TEST pin state, and no performance or functionality depends on its connection.