Texas Instruments TLC5946PW

Overview

TLC5946PW from Texas Instruments is a 16-channel, 12-bit PWM LED driver with integrated 6-bit dot correction, operating as a constant-current sink for monochrome/multicolor LED displays. It delivers up to 40 mA per channel, supports 30-MHz serial data transfer and 33-MHz grayscale PWM clocking, and features LED open detection (LOD) and thermal error flag (TEF) for system reliability in outdoor signage and backlighting applications.

For engineers reviewing the TLC5946PW datasheet, TLC5946PW pinout, TLC5946PW application, or TLC5946PW equivalent, key selection criteria include its TSSOP-28 package, 4096-step grayscale resolution, 64-step dot correction per channel, IREF-based current setting, and dual-mode serial interface (MODE pin controlled) for independent grayscale and dot correction programming.

Technical Context

The TLC5946PW implements a dual-latch serial architecture: a 96-bit shift register for dot correction (DC) mode and a 192-bit shift register for grayscale (GS) mode, selected via the MODE pin. Its grayscale timing uses a 12-bit counter driven by GSCLK, resetting on BLANK high, with output on-time directly proportional to programmed GS value (0–4095) and GSCLK period.

Dot correction adjusts each channel's current from 0% to 100% of I_OLCMax in 64 discrete steps (0–63), enabling per-LED brightness/color matching. Current accuracy is ±1% (channel-to-channel) and ±2% (device-to-device), set by a single external resistor (RIREF) tied between IREF and GND, where VIREF = 1.20 V (typ).

Key Specifications

Pinout & Package

TLC5946PW is housed in a 28-pin TSSOP (Thin Shrink Small Outline Package) with exposed thermal pad (PowerPAD not implemented in PW variant). Pin pitch is 0.65 mm; body dimensions are 9.7 mm × 4.4 mm × 1.2 mm. The package is RoHS-compliant and designed for surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5946PW, TLC5947PWP offers superior thermal performance in thermally constrained designs, while TLC59283PWR reduces BOM cost where per-channel calibration and real-time fault detection are unnecessary-making TLC5946PW the optimal balance of precision, diagnostics, and package compatibility for demanding LED systems.

Availability

TLC5946PW is available at Aetrix Electronics and suitable for outdoor signage, industrial HMIs, and architectural lighting requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for TLC5946PW 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 decades of expertise in precision power management and LED control solutions.

The TLC5946PW belongs to TI's high-accuracy LED driver product line, engineered specifically for applications demanding per-pixel luminance uniformity, real-time fault detection, and robust operation across industrial temperature ranges.

FAQ

What is the maximum LED forward voltage supported by the TLC5946PW?

The TLC5946PW supports an output voltage range of –0.3 V to +18 V at OUT0–OUT15 pins, enabling direct drive of LED strings with up to 17 V total forward voltage. This allows use with high-V_F UV, white, or multi-die LEDs without external boost circuitry-critical for outdoor signage where long LED strings reduce wiring complexity. The TLC5946PW maintains 40 mA sink capability across this full range when VCC ≥ 3.0 V.

How does the IREF pin set the output current in the TLC5946PW?

The IREF pin on the TLC5946PW connects to an internal 1.20 V (typ) bandgap reference. An external resistor (RIREF) between IREF and GND sets the maximum sink current per channel (IOLCMax) using IOLCMax ≈ 42.5 × (1.20 V / RIREF). For example, RIREF = 1.3 kΩ yields ~39 mA. The TLC5946PW guarantees ±1% channel-to-channel matching and ±2% device-to-device consistency across the 4–40 mA range, making it ideal for high-fidelity displays.

Can the TLC5946PW detect open-circuit LEDs during normal operation?

Yes-the TLC5946PW integrates continuous LED open detection (LOD) that operates during active display periods. When an LED disconnects or fails open, the corresponding OUTn pin voltage rises above 0.4 V (VLOD threshold), triggering the XERR pin to assert low within 20–40 ns (tD1). This real-time fault flag enables immediate system-level response-such as disabling the faulty zone or logging the event-without interrupting other channels' PWM operation.

What is the function of the MODE and XLAT pins on the TLC5946PW?

The MODE pin selects serial data load mode: HIGH configures the TLC5946PW to accept 96-bit dot correction (DC) data; LOW selects 192-bit grayscale (GS) data. The XLAT pin provides the rising-edge latch signal that transfers data from the shift register into the respective DC or GS latch. Critically, new data become active immediately upon XLAT assertion-even mid-PWM cycle-so proper sequencing (latching during BLANK high) prevents visual artifacts in the TLC5946PW output.

Does the TLC5946PW support daisy-chaining, and how many devices can be cascaded?

Yes-the TLC5946PW supports seamless daisy-chaining via its SOUT pin, which outputs shifted data to the next device's SIN pin. With 30-MHz SCLK capability and deterministic 25-ns propagation delay (tD0), the TLC5946PW enables reliable cascading of 10+ devices in a single chain. Each additional TLC5946PW adds 96 or 192 bits to the serial frame, but timing margins remain sufficient for full-speed operation-verified in TI's typical application circuit with multiple TLC5946PW units.