Texas Instruments TLC5946PWR

Overview

TLC5946PWR 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 features LED open detection (LOD) and thermal error flag (TEF) circuits. Used in LED signboards and display backlighting where precise grayscale and per-channel brightness calibration are required.

For engineers reviewing the TLC5946PWR datasheet, TLC5946PWR pinout, TLC5946PWR application, or TLC5946PWR equivalent, key selection criteria include its 12-bit grayscale resolution (4096 steps), 6-bit dot correction (64 steps), 33-MHz GSCLK capability, TSSOP-28 package with PowerPAD™ thermal enhancement, and dual-error reporting via open-drain XERR.

Technical Context

The TLC5946PWR implements a dual-stage serial interface: MODE pin selects between 96-bit dot correction (DC) or 192-bit grayscale (GS) data loading, both shifted in MSB-first via SIN/SCLK. Grayscale timing is driven by an internal 12-bit counter synchronized to GSCLK, resetting on BLANK high.

Constant current per channel is set by a single external resistor (RIREF) tied to IREF, generating a nominal 1.20 V reference; output accuracy is ±1% channel-to-channel and ±2% device-to-device. Error detection includes continuous LOD (0.2–0.4 V threshold) and TEF activation at +150°C to +175°C junction temperature.

Key Specifications

Pinout & Package

TLC5946PWR uses the TSSOP-28 (PW) package with exposed thermal pad (PowerPAD™). Pin numbering follows standard top-view layout; pins 1–28 correspond to GND, BLANK, XLAT, SCLK, SIN, MODE, OUT0–OUT7, VCC, IREF, XHALF, GSCLK, SOUT, XERR, OUT8–OUT15.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5946PWR, TLC5947PWR offers identical functionality in a thermally superior QFN package with higher LED voltage headroom, while IS31FL3728-QFLS4-TR provides greater channel count and nonvolatile configuration storage-neither is pin-compatible, but both address adjacent design requirements in LED system scaling and thermal management.

Availability

TLC5946PWR is available at Aetrix Electronics and suitable for LED signboards, display backlighting, and instrument panel lighting requiring stable component supply, long-term manufacturability, and automotive-grade temperature operation (−40°C to +85°C).

Supply support for TLC5946PWR 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 and embedded processing technologies, with decades of expertise in precision power management and LED control ICs.

The TLC5946PWR belongs to TI's high-accuracy LED driver product line, designed specifically for applications demanding per-channel current matching, real-time fault detection, and seamless integration with microcontroller-based display controllers.

FAQ

What is the maximum LED supply voltage supported by the TLC5946PWR?

The TLC5946PWR supports an output voltage range of −0.3 V to +18 V on OUT0–OUT15. This allows driving LED strings with total forward voltage up to 17 V, accommodating typical configurations of 4–5 white LEDs (3.4 V each) or 8–10 red LEDs (2.0 V each) without external boost circuitry. The absolute maximum rating is 18 V; operation above 17 V is not recommended for reliability.

How does the TLC5946PWR achieve channel-to-channel current matching of ±1%?

The TLC5946PWR achieves ±1% channel-to-channel current matching through matched internal current mirror circuitry and precision bandgap reference (VIREF = 1.20 V ±0.04 V). Each output stage shares the same reference and bias structure, minimizing process-induced mismatches. Matching is specified at TA = −40°C to +85°C, VCC = 3.0–5.5 V, and RIREF = 1.3 kΩ, with typical performance tighter than ±0.7% under nominal conditions.

Can the TLC5946PWR be used without connecting the IREF pin?

No - the TLC5946PWR requires an external resistor (RIREF) connected between IREF and GND to set the maximum output current (IOLCMax). Without this resistor, the internal reference current path is incomplete and no regulated sink current flows. RIREF must be between 1.275 kΩ and 12.75 kΩ to ensure stable operation across the 4–40 mA per-channel range; values outside this range may cause instability or reduced accuracy.

What happens when the XERR pin goes low during operation?

When XERR goes low, it indicates either LED open detection (LOD) - meaning one or more OUTx pins detected <0.2 V while expected to be sinking current - or thermal error flag (TEF) activation due to junction temperature exceeding +150°C. XERR is open-drain and must be pulled up externally; its assertion halts normal PWM operation until the fault condition is cleared and BLANK is pulsed to reset internal latches. The TLC5946PWR does not auto-recover - host MCU must read status and take corrective action.

Is the TLC5946PWR compatible with 3.3-V microcontrollers for serial communication?

Yes - the TLC5946PWR features CMOS-level I/O with VIH = 0.7 × VCC and VIL = 0.3 × VCC, making it fully compatible with 3.3-V logic. When VCC = 3.3 V, valid high input is ≥2.31 V and low input is ≤0.99 V. All control pins (SCLK, SIN, XLAT, MODE, BLANK, XHALF) meet this specification, and SOUT/XERR outputs swing rail-to-rail, ensuring reliable interfacing without level-shifting circuitry.