Texas Instruments TLC5917IN

Overview

TLC5917IN from Texas Instruments is an 8-channel constant-current LED sink driver IC designed for precise current control in LED display and lighting systems. It delivers 3–120 mA per channel with ±3% inter-channel current matching, supports 3.0–5.5 V supply, and features open-load, short-load (TLC5917 only), and overtemperature detection - enabling robust fault monitoring in video billboards and industrial signage.

For engineers reviewing the TLC5917IN datasheet, TLC5917IN pinout, TLC5917IN application, or TLC5917IN equivalent, key selection considerations include its 30-MHz serial interface, R-EXT–based current programming, error status readback via SDO, and support for cascaded configurations in high-density LED arrays.

Technical Context

The TLC5917IN integrates an 8-bit shift register, output latches, and eight independent constant-current sinks with integrated thermal and electrical fault sensing. Its dual-mode operation-Normal Mode for data loading and Special Mode for error/status readback or global current gain adjustment-relies on edge-triggered LE(ED1) and pulse-width–sensitive OE(ED2) control signals.

Unlike the TLC5916, the TLC5917IN adds short-to-VLED detection using dual voltage thresholds (2.5–3.1 V trigger, 2.2 V return), enabling reliable identification of LED short-circuit faults while maintaining identical pinout, timing, and current regulation architecture across the family.

Key Specifications

Pinout & Package

Package: 16-pin SOIC (9.90 mm × 3.91 mm), PDIP (19.30 mm × 6.35 mm), or TSSOP (5.00 mm × 4.40 mm); TLC5917IN specifically uses SOIC (N) package per TI orderable addendum.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant-current LED sink driver applications.

Compared with TLC5916IN, the TLC5917IN adds short-load detection at no pinout or timing penalty; versus MAX7219CWG+, it offers wider current range, discrete channel control, and superior fault coverage - making it optimal for high-reliability linear LED arrays.

Availability

TLC5917IN is available at Aetrix Electronics and suitable for video billboards, industrial signage, gaming machine displays, and white goods UI panels requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for TLC5917IN 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 over 50 years of innovation in power management and interface solutions.

The TLC5917IN belongs to TI's constant-current LED driver product line, engineered specifically for high-reliability, fault-aware LED display systems where uniform brightness, thermal resilience, and real-time diagnostics are critical.

FAQ

What is the maximum output voltage rating for the TLC5917IN?

The TLC5917IN supports a maximum output voltage of 20 V at its OUT0–OUT7 pins. This allows direct driving of multi-LED series strings or high-forward-voltage LEDs without external voltage boosting circuitry. The 20-V rating applies across the full operating temperature range (–40°C to +125°C) and is specified in the Absolute Maximum Ratings table of the SLVS695D datasheet. This headroom ensures compatibility with common white and blue LEDs, as well as legacy red/green/yellow variants.

Does the TLC5917IN support daisy-chaining with other LED drivers?

Yes, the TLC5917IN supports seamless daisy-chaining via its SDI and SDO pins. Serial data shifted into SDI propagates through the internal 8-bit shift register and exits SDO, enabling connection to the SDI of the next TLC5917IN (or TLC5916IN) in the chain. This architecture allows scalable control of dozens of channels using only three MCU pins (CLK, LE, OE). The 30-MHz clock capability ensures minimal latency even in long cascades - verified in TI's Typical Application section (Figure 24).

How does short-load detection work on the TLC5917IN?

The TLC5917IN implements short-load detection by monitoring output voltage (VOUT) against two thresholds: a trigger threshold (2.5–3.1 V) and a return threshold (2.2 V). When a channel is active and VOUT exceeds the trigger level, the device flags a short-to-VLED condition in its error register. The hysteresis prevents chatter during marginal conditions. This feature is exclusive to TLC5917IN - the TLC5916IN lacks it entirely - and requires the channel to be ON for detection to activate, as documented in Section 9.3.2 of SLVS695D.

Can the TLC5917IN drive LEDs at different current levels simultaneously?

No - the TLC5917IN sets a single output current level for all eight channels via the external R-EXT resistor. However, individual channels can be digitally switched ON/OFF to create variable effective brightness (e.g., PWM via host controller), and the 256-step global current gain allows runtime adjustment of the full-scale current value. For true per-channel current tuning, a different device such as the TLC5947 would be required. The TLC5917IN's design prioritizes simplicity, matching, and fault coverage over per-channel current programming.

What thermal protection mechanisms does the TLC5917IN include?

The TLC5917IN incorporates dual-layer thermal protection: a global junction sensor that shuts down all outputs if TJ exceeds 150–200°C, and eight independent channel-specific sensors that disable only the affected output under localized overheating. Both modes store error status persistently until cleared by returning to Normal Mode. After cooling, outputs automatically restart if their latch remains active. Thermal metrics (e.g., RθJA = 87.4°C/W for SOIC) are provided in Section 7.4 of SLVS695D to support board-level thermal design.