Texas Instruments TLC5945RHBR

Overview

TLC5945RHBR from Texas Instruments is a 16-channel constant-current LED driver IC with integrated 12-bit grayscale PWM control (4096 steps) and 6-bit dot correction (64 steps), supporting up to 80 mA per channel and LED supply voltage up to 17 V. It operates from 3.0 V to 5.5 V, features serial interface with 30-MHz SCLK, and delivers precise brightness uniformity for full-color LED displays.

For engineers reviewing the TLC5945RHBR datasheet, TLC5945RHBR pinout, TLC5945RHBR application, or TLC5945RHBR equivalent, key selection criteria include its dual-register architecture (GS/DC), open-drain XERR error reporting (LOD/TEF), thermal error flag threshold at 160°C typical, and QFN-32 package with PowerPAD™ for thermal management.

Technical Context

The TLC5945RHBR implements a synchronous grayscale PWM engine driven by GSCLK, where each of 16 outputs is individually controlled by a 12-bit grayscale register and a 6-bit dot correction register. Grayscale counter advances on every GSCLK rising edge, comparing against programmed GSn values to determine ON/OFF state per channel within the 4096-step cycle.

Dot correction is applied multiplicatively to maximum sink current (Imax = 31.5 × I_IREF) to fine-tune per-channel output across temperature and LED variance. Error detection is hardware-asserted: LED Open Detection triggers when OUTn voltage falls below 0.3 V (typ) during active drive, and Thermal Error Flag activates at junction temperature >160°C (typ), both driving open-drain XERR low.

Key Specifications

Pinout & Package

The TLC5945RHBR is housed in a 32-pin 5 mm × 5 mm QFN package with exposed thermal pad (PowerPAD™), rated at 35.9°C/W junction-to-board thermal impedance when soldered with 2-oz copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5945RHBR, TLC5947RGER offers higher integration per package but requires identical PCB layout effort; IS31FL3731-QFLS4-TR trades serial timing complexity for I²C simplicity and embedded memory, at the cost of fixed matrix topology and lower max current (40 mA).

Availability

TLC5945RHBR is available at Aetrix Electronics and suitable for LED signboards, full-color video displays, and automotive interior lighting requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for TLC5945RHBR 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 reliability.

The TLC5945RHBR belongs to TI's high-accuracy LED driver product line, designed specifically for demanding visual applications where brightness uniformity, thermal robustness, and fault visibility are critical-such as outdoor signage and automotive displays.

FAQ

What is the maximum output current per channel for the TLC5945RHBR?

The TLC5945RHBR supports a maximum constant-current sink of 80 mA per channel (OUT0–OUT15), set by an external resistor on the IREF pin. Using the internal 1.24 V reference and the scaling factor of 31.5, R_IREF = 640 Ω yields Imax = 80 mA. Current accuracy remains within ±4% across channels at this setting, as specified in the Electrical Characteristics table of the TLC5945RHBR datasheet.

How does the TLC5945RHBR handle LED open-circuit faults?

The TLC5945RHBR performs real-time LED open detection (LOD) on each output: when an OUTn channel is actively sinking current and its voltage drops below 0.3 V (typical), the LOD flag is asserted. This condition latches into the Status Information Data (SID) register and pulls the open-drain XERR pin low. The SID can then be read via SOUT to identify the exact faulty channel (bits 0–15), enabling targeted diagnostics without external circuitry.

Can the TLC5945RHBR operate with a 3.3 V supply?

Yes, the TLC5945RHBR operates across a supply range of 3.0 V to 5.5 V, fully supporting 3.3 V logic and power domains. All digital inputs (SIN, SCLK, XLAT, MODE, BLANK, GSCLK) meet CMOS level thresholds at 3.3 V (VIH ≥ 2.64 V, VIL ≤ 0.66 V), and the IREF reference remains stable at 1.24 V. The TLC5945RHBR maintains full 80 mA sink capability and 30 MHz SCLK performance at 3.3 V, as validated in the Recommended Operating Conditions table.

What is the function of the MODE pin on the TLC5945RHBR?

The MODE pin selects between two distinct serial data protocols on the TLC5945RHBR: when pulled to GND, it enables Grayscale (GS) mode with a 192-bit input shift register for 12-bit data per channel; when pulled to VCC, it enables Dot Correction (DC) mode with a 96-bit register for 6-bit per-channel correction values. The MODE state must be stable before each XLAT pulse, and switching modes requires XLAT to be low during the transition to avoid data corruption in the TLC5945RHBR internal latches.

Does the TLC5945RHBR require an external clock source for grayscale PWM?

Yes, the TLC5945RHBR requires an external GSCLK signal to drive its grayscale PWM counter. GSCLK is a free-running clock input (pin 24 in RHB package) with frequency up to 30 MHz; each rising edge increments the 12-bit counter, which compares against stored GSn values to determine output ON/OFF states. Unlike self-timed drivers, the TLC5945RHBR provides deterministic, jitter-free PWM timing controlled entirely by the system's GSCLK generator, ensuring synchronization across multiple ICs in large displays.