Texas Instruments TLC5946RHBRG4

Overview

TLC5946RHBRG4 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 (4096 steps) and per-channel brightness calibration for high-fidelity monochrome/multicolor LED displays.

For engineers reviewing the TLC5946RHBRG4 datasheet, TLC5946RHBRG4 pinout, TLC5946RHBRG4 application, or TLC5946RHBRG4 equivalent, key selection criteria include its 33 MHz grayscale PWM clock, ±1% channel-to-channel current accuracy, open-drain XERR error flag for LED open/thermal detection, and QFN-32 package with exposed thermal pad for thermal management in dense LED signage layouts.

Technical Context

The TLC5946RHBRG4 implements dual-mode serial interface control: MODE = high enables 96-bit dot correction data loading (6 bits × 16 channels), while MODE = low enables 192-bit grayscale PWM data loading (12 bits × 16 channels). Data is shifted in MSB-first via SIN/SCLK and latched on XLAT rising edge.

Its internal architecture includes a 12-bit grayscale counter synchronized to GSCLK (up to 33 MHz), four-grouped output delay for reduced EMI, and independent LOD (LED open detection) and TEF (thermal error flag) circuits monitored through open-drain XERR. BLANK resets the grayscale counter and forces all outputs OFF.

Key Specifications

Pinout & Package

Package: 5 mm × 5 mm QFN-32 with exposed thermal pad (PowerPAD™), RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5946RHBRG4, TLC5947RGER offers higher channel count in identical footprint and thermal performance, while MAX6966AUG+T trades dot correction and error flags for I²C simplicity and lower unit cost-making it suitable only where per-channel calibration and fault monitoring are non-critical.

Availability

TLC5946RHBRG4 is available at Aetrix Electronics and suitable for LED signboards, full-color video walls, and automotive interior lighting requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for TLC5946RHBRG4 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 components for industrial, automotive, and consumer applications.

The TLC5946RHBRG4 belongs to TI's precision LED driver product line, engineered for high-density, high-reliability LED display systems demanding per-pixel current accuracy, real-time fault detection, and thermal robustness in compact form factors.

FAQ

What is the maximum LED forward voltage supported by the TLC5946RHBRG4?

The TLC5946RHBRG4 supports an output voltage range of –0.3 V to +18 V at its OUT0–OUT15 pins, enabling direct drive of LED strings with up to 17 V total forward voltage. This accommodates common high-brightness RGB configurations and multi-LED series chains without external boost circuitry, provided the external LED supply rail meets the 17 V ceiling and remains within the device's absolute maximum ratings.

How does the TLC5946RHBRG4 implement LED open detection (LOD)?

The TLC5946RHBRG4 performs continuous LED open detection during active display periods by monitoring voltage at each OUTn pin. When an LED is disconnected or fails open, the corresponding output voltage rises above the 0.2–0.4 V LOD threshold, triggering the XERR pin to assert low. This occurs independently per channel and operates concurrently with grayscale PWM, allowing real-time fault identification without interrupting display operation.

Can the TLC5946RHBRG4 be daisy-chained, and what pin enables this?

Yes, the TLC5946RHBRG4 supports daisy-chaining via its SOUT pin (Pin 23), which outputs delayed serial data after 96 or 192 bits depending on MODE state. The XHALF pin (Pin 25) must be held low to activate the extended serial interface mode required for reliable multi-device cascading. This eliminates the need for external multiplexers or additional GPIOs when driving large-scale LED arrays.

What external component sets the maximum output current for all 16 channels of the TLC5946RHBRG4?

A single external resistor (RIREF) connected between the IREF pin (Pin 26) and GND sets the maximum sink current for all 16 channels. With a typical internal IREF voltage of 1.20 V, RIREF = 1.3 kΩ yields ~40 mA per channel. The relationship is I_OLCMax ≈ 42.5 × V_IREF/R_IREF, and RIREF must remain between 1.275 kΩ and 12.75 kΩ to maintain stable operation across the 4–40 mA range.

Does the TLC5946RHBRG4 require BLANK to be asserted high before updating grayscale or dot correction data?

No-BLANK does not need to be high to latch new data. The XLAT rising edge immediately transfers data from the shift register to the grayscale or dot correction latch, making values effective even while outputs are active. However, TI recommends asserting BLANK high during power-up and before initial data load to prevent undefined output states, and latching grayscale data only when BLANK is high to avoid mid-cycle glitches that could cause visible flicker or transient brightness errors in the TLC5946RHBRG4.