Texas Instruments TLC5946RHBTG4

Overview

TLC5946RHBTG4 from Texas Instruments is a 16-channel, 12-bit PWM LED driver with integrated 6-bit dot correction, operating as a constant-current sink with 40 mA per channel capability and supporting LED power supply voltages up to 17 V. It delivers precise grayscale control for monochrome and full-color LED displays via serial interface, with real-time open-LED detection and thermal error flagging.

For engineers reviewing the TLC5946RHBTG4 datasheet, TLC5946RHBTG4 pinout, TLC5946RHBTG4 application, or TLC5946RHBTG4 equivalent, key selection criteria include its 33 MHz grayscale PWM clock, ±1% typical channel-to-channel current accuracy, daisy-chainable serial interface, and QFN-32 PowerPAD™ package optimized for thermal management in high-density LED signage and backlighting designs.

Technical Context

The TLC5946RHBTG4 implements dual-stage serial control: a 96-bit shift register for 6-bit dot correction (DC) data and a 192-bit shift register for 12-bit grayscale (GS) PWM data, selected by the MODE pin. Grayscale timing is driven by an external GSCLK input up to 33 MHz, while dot correction adjusts per-channel current from 0% to 100% of I_OLCMax in 64 discrete steps.

It integrates two independent error detection circuits: LED open detection (LOD) triggers at ≤0.3 V across OUTn under active drive, and thermal error flag (TEF) activates at +150°C junction temperature with +10°C hysteresis. Both errors assert the open-drain XERR output, enabling system-level fault monitoring without additional circuitry.

Key Specifications

Pinout & Package

The TLC5946RHBTG4 is housed in a 5 mm × 5 mm QFN-32 package with exposed thermal pad (PowerPAD™), rated for 3482 mW maximum power dissipation at TA = +25°C when mounted on 2 oz copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5947RGER and IS31FL3731-QFLS4-TR, the TLC5946RHBTG4 uniquely balances high channel density, hardware-enforced fault detection, and flexible serial timing - making it optimal for industrial LED arrays where reliability and deterministic error response outweigh interface convenience.

Availability

TLC5946RHBTG4 is available at Aetrix Electronics and suitable for LED signboards, full-color video walls, automotive display backlights, and industrial HMI panel lighting requiring stable component supply across long production lifecycles.

Supply support for TLC5946RHBTG4 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 technologies, with decades of expertise in precision LED control and industrial-grade IC design.

The TLC5946RHBTG4 belongs to TI's high-accuracy LED driver product line, engineered specifically for demanding visual applications where per-pixel current consistency, real-time fault awareness, and thermal resilience are non-negotiable design requirements.

FAQ

What is the maximum LED supply voltage supported by the TLC5946RHBTG4?

The TLC5946RHBTG4 supports LED power-supply voltages up to 17 V on its OUT0–OUT15 pins. This allows direct connection to common 12 V and 15 V LED strings without external boost circuitry, while maintaining full 40 mA sink capability across the specified operating temperature range of –40°C to +85°C. The absolute maximum rating is +18 V, but sustained operation above 17 V is not recommended per TI's published specifications for the TLC5946RHBTG4.

How does the TLC5946RHBTG4 implement dot correction and grayscale control?

The TLC5946RHBTG4 uses separate 96-bit and 192-bit shift registers for dot correction (6-bit per channel) and grayscale (12-bit per channel). When MODE is high, serial data on SIN is loaded into the dot correction register; when MODE is low, it loads grayscale data. XLAT latches the data, and GSCLK drives the PWM counter. This dual-path architecture lets designers calibrate LED variations first (dot correction), then animate content (grayscale), both using the same serial interface - a core feature of the TLC5946RHBTG4.

Can the TLC5946RHBTG4 be daisy-chained, and what pins enable this?

Yes, the TLC5946RHBTG4 supports seamless daisy-chaining via its dedicated serial interface: SIN receives data, SCLK clocks it in, and SOUT outputs the shifted-out data to the next device's SIN pin. This 3-wire topology eliminates parallel bus routing and reduces MCU GPIO usage. Up to 32 devices can be chained without signal degradation when using proper PCB layout practices and termination - a capability confirmed in TI's application notes for the TLC5946RHBTG4.

What thermal protection features does the TLC5946RHBTG4 provide?

The TLC5946RHBTG4 integrates a thermal error flag (TEF) that asserts the open-drain XERR pin when junction temperature exceeds +150°C, with +10°C hysteresis for stable recovery. Unlike software-based thermal monitoring, this hardware flag operates independently of clock or data activity, ensuring fail-safe shutdown even during communication faults. The QFN-32 PowerPAD™ package further enhances thermal performance, delivering 3482 mW dissipation capability at +25°C ambient - a key reliability attribute of the TLC5946RHBTG4.

How is the output current set on the TLC5946RHBTG4?

The TLC5946RHBTG4 sets its maximum per-channel output current (I_OLCMax) using a single external resistor (RIREF) between the IREF pin and GND. With a fixed 1.20 V internal bandgap reference, I_OLCMax = 42.5 × (1.20 V / RIREF). For example, a 1.3 kΩ resistor yields ~39 mA. TI specifies RIREF between 1.275 kΩ and 12.75 kΩ to maintain stable operation from 4 mA to 40 mA - a simple, predictable method unique to the TLC5946RHBTG4 among TI's LED driver portfolio.