Texas Instruments TLC5940PWPRG4

Overview

TLC5940PWPRG4 from Texas Instruments is a 16-channel constant-current sink LED driver with 12-bit (4096-step) grayscale PWM control, 6-bit (64-step) dot correction stored in integrated EEPROM, and simultaneous LED open detection (LOD) and thermal error flag (TEF). It supports up to 120 mA per channel at VCC > 3.6 V and operates from 3 V to 5.5 V supply, used in full-color LED displays requiring precise per-channel brightness calibration.

For engineers reviewing the TLC5940PWPRG4 datasheet, TLC5940PWPRG4 pinout, TLC5940PWPRG4 application, or TLC5940PWPRG4 equivalent, key selection criteria include its serial 3-wire interface (SIN/SCLK/XLAT), GSCLK/BLANK timing control, IREF-based current programming, and open-drain XERR error reporting - all critical for cascaded LED display systems with fault monitoring.

Technical Context

The TLC5940PWPRG4 implements dual-mode serial data loading: grayscale (GS) data (96 bits) and dot correction (DC) data (192 bits), selected via VPRG logic level. Its internal architecture includes independent 12-bit GS counters per channel, 6-bit DC registers with EEPROM backup, and graduated 20-ns inter-channel output delays (0–300 ns across OUT0–OUT15) to suppress inrush current.

LED open detection triggers when OUTn voltage falls below 0.3 V while active; thermal error flag activates at junction temperature ≥150 °C. Both errors drive the open-drain XERR pin low and are latched into a status register readable via SOUT during serial shift-out, enabling real-time system-level fault diagnostics without interrupt pins.

Key Specifications

Pinout & Package

Package: HTSSOP-28 (PWP), 9.70 mm × 4.40 mm body, exposed thermal pad (PowerPAD™).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC5940PWPRG4, TLC5941IPWPR offers enhanced reliability and timing flexibility without layout changes, while MAX6966ATL+ reduces BOM count but shifts calibration complexity to firmware - making TLC5940PWPRG4 optimal for field-serviceable, high-uniformity LED systems.

Availability

TLC5940PWPRG4 is available at Aetrix Electronics and suitable for full-color LED video walls, industrial signage, medical display backlights, and stage lighting systems requiring stable component supply, long-term calibration retention, and real-time fault reporting.

Supply support for TLC5940PWPRG4 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 solutions, with decades of expertise in precision power management and interface ICs.

The TLC5940 product line was designed specifically for high-fidelity, multi-channel LED current control in professional display and lighting applications demanding per-pixel grayscale accuracy and long-term brightness stability.

FAQ

What is the maximum output current per channel for the TLC5940PWPRG4?

The TLC5940PWPRG4 supports up to 120 mA per channel when VCC exceeds 3.6 V, set by the external IREF resistor. At VCC < 3.6 V, the limit is 60 mA. The actual current is calculated as IOUT = 31.5 × V(IREF)/R(IREF), where V(IREF) is typically 1.24 V. For example, a 640 Ω resistor yields ~60 mA per channel. This value is confirmed in Section 6.3 of the SLVS515D datasheet.

How does the TLC5940PWPRG4 implement LED open detection (LOD)?

The TLC5940PWPRG4 detects open LEDs by monitoring OUTn voltage during active drive: if OUTn drops below 0.3 V while enabled, LOD triggers and pulls XERR low. The condition must persist for ≥1 μs (tpd2) to avoid false positives. LOD status is latched into the internal status register on the falling edge of XLAT and can be read back via SOUT. This behavior is documented in Sections 8.3.4 and Table 1 of the datasheet.

Can multiple TLC5940PWPRG4 devices be cascaded, and how is data routed?

Yes, TLC5940PWPRG4 devices support daisy-chaining: SOUT of one device connects to SIN of the next, sharing SCLK and XLAT. Each device receives 96-bit (GS) or 192-bit (DC) data; total serial length scales linearly (e.g., two devices = 192 or 384 bits). Status readback also cascades - the first device's SOUT returns its own status, followed by downstream devices' data. This is detailed in Figures 12–13 and Section 8.3.1.

What is the role of the VPRG and DCPRG pins on the TLC5940PWPRG4?

VPRG selects operational mode: low = grayscale (GS) data load, high = dot correction (DC) data load, and 20–23 V = EEPROM programming mode. DCPRG controls data path: low connects DC register to EEPROM for read/write; high connects it to the shift register. Together, they enable in-system calibration updates without removing the TLC5940PWPRG4 from the board, as specified in Pin Functions Table and Section 8.3.7.

Does the TLC5940PWPRG4 require external components for basic operation?

Yes - the TLC5940PWPRG4 requires at minimum: (1) an external IREF resistor to set output current, (2) pull-up resistors on XERR and SOUT (for status readback), and (3) bypass capacitors on VCC. Optional components include series resistors on digital inputs for ESD protection. No external clock generator is needed for GSCLK or SCLK, as both are provided by the host controller. These requirements are listed in Section 10 (Power Supply Recommendations) and Figure 22.