Texas Instruments TLC5940QRHBREP

Overview

TLC5940QRHBREP from Texas Instruments is a 16-channel, constant-current sink LED driver IC with 12-bit grayscale PWM control (4096 steps), integrated 6-bit dot correction (64 steps) stored in EEPROM, and dual error detection (LED open detection and thermal error flag). It supports up to 120 mA per channel at VCC > 3.6 V and −40°C to 125°C operation, used in high-reliability full-color LED displays and defense-grade signage.

For engineers reviewing the TLC5940QRHBREP datasheet, TLC5940QRHBREP pinout, TLC5940QRHBREP application, or TLC5940QRHBREP equivalent, key selection considerations include its VQFN-32 package, 30 MHz serial interface speed, IREF-based current programming, open-drain XERR error reporting, and EP-grade qualification for extended temperature and lifecycle support.

Technical Context

The TLC5940QRHBREP implements a dual-register serial architecture: grayscale (GS) data controls 12-bit PWM timing per channel, while dot correction (DC) data adjusts per-channel current gain via 6-bit scaling. GSCLK drives the PWM counter; SCLK shifts 192-bit data (16 × 12-bit GS + 16 × 6-bit DC); XLAT latches data into active registers. VPRG selects between GS mode (low), DC mode (high), or EEPROM programming (20–23 V).

Error handling is hardware-synchronized: LED open detection triggers when OUTn voltage exceeds 0.3–0.4 V (indicating open-circuit LED), and thermal error flag activates at junction temperature ≥150°C (typical 160°C). Both faults drive the open-drain XERR output low, with LOD maskable via BLANK = HIGH.

Key Specifications

Pinout & Package

Package: VQFN-32 (5.00 mm × 5.00 mm, 0.5 mm pitch, exposed thermal pad).

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 TLC5940QRHBREP uniquely combines EEPROM-stored dot correction, 16-channel precision sinking, and EP-grade reliability-making it irreplaceable in defense, aerospace, and medical LED systems where calibration integrity and long-term stability are non-negotiable.

Availability

TLC5940QRHBREP is available at Aetrix Electronics and suitable for monocolor signage, full-color RGB displays, and aerospace cabin lighting requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for TLC5940QRHBREP 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 ICs, with decades of heritage in precision power and signal chain solutions.

The TLC5940QRHBREP belongs to TI's Enhanced Plastic (EP) product line-engineered for defense, aerospace, and medical applications demanding extended temperature operation, controlled baselines, and full traceability.

FAQ

What is the maximum safe operating current per channel for TLC5940QRHBREP at 125°C?

The TLC5940QRHBREP supports up to 72 mA per channel across the full −40°C to +125°C ambient temperature range. This rating assumes proper PCB thermal design with the exposed thermal pad soldered to a sufficient copper area. At 125°C, current must be derated per the device's thermal resistance (RθJA = 36.7°C/W for VQFN), and the 72 mA value reflects worst-case junction temperature limits under continuous operation.

How does the TLC5940QRHBREP implement dot correction, and where is the data stored?

The TLC5940QRHBREP uses 6-bit dot correction values to scale each channel's constant-current sink independently, compensating for LED forward-voltage variation and driver mismatch. These 64-step correction factors are written to and retained in the device's integrated EEPROM-preserving calibration across power cycles without external memory. Programming requires VPRG = 20–23 V and DCPRG = HIGH.

Can TLC5940QRHBREP detect open LEDs during active PWM operation?

Yes. The TLC5940QRHBREP performs LED open detection (LOD) continuously during normal operation by monitoring voltage at each OUTn pin. If the voltage exceeds 0.3–0.4 V (indicating no current flow through the LED), LOD asserts and pulls XERR low. LOD remains active even while GSCLK is running - though it can be temporarily masked by setting BLANK = HIGH.

What is the function of the XERR pin on TLC5940QRHBREP, and how should it be interfaced?

The XERR pin on TLC5940QRHBREP is an open-drain output that goes low when either LED open detection (LOD) or thermal error flag (TEF) is triggered. It requires an external pull-up resistor (typically 4.7–10 kΩ to VCC). Multiple TLC5940QRHBREP devices can share one XERR bus - enabling system-level fault aggregation with a single MCU interrupt input.

Does TLC5940QRHBREP support daisy-chaining, and what is the maximum number of devices in series?

Yes. The TLC5940QRHBREP supports unlimited daisy-chaining via SIN → SOUT connections. Each device accepts 192-bit serial data (16 × 12-bit GS + 16 × 6-bit DC), and SOUT forwards shifted-out data to the next device's SIN. There is no hard limit on cascade length - practical constraints are governed by SCLK timing margin, PCB trace length, and total propagation delay across the chain.