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Texas Instruments TLC5955RTQT
- Part No.:
- TLC5955RTQT
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 56-VFQFN Exposed Pad
- Datasheet:
-
TLC5955RTQT.pdf
- Description:
- IC LED DRV LIN 23.9/31.9MA 56QFN
- Quantity:
- Payment:
- Shipping:
Inventory:250
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Product details
Overview
TLC5955RTQT from Texas Instruments is a 48-channel, 16-bit PWM LED driver IC with integrated dot correction (DC), global brightness control (BC), and LED open/short detection. It delivers constant-current sink outputs up to 31.9 mA per channel (VCC > 3.6 V), supports 65,536-step grayscale control, and operates across –40°C to +85°C for high-reliability LED video displays.
For engineers reviewing the TLC5955RTQT datasheet, TLC5955RTQT pinout, TLC5955RTQT application, or TLC5955RTQT equivalent, key selection considerations include its QFN-56 package, 33 MHz GSCLK timing, 25 MHz data transfer rate, 7-bit DC/BC resolution, and dual error-detection capability for field-deployed signage systems.
Technical Context
The TLC5955RTQT implements a 769-bit serial interface with MSB-driven command decoding: MSB = 0 loads grayscale data into the 768-bit GS latch; MSB = 1 with header 96h loads control data (MC/BC/DC/FC) into the 371-bit control latch. Its internal current reference eliminates external Rset components.
Each of the 48 outputs (16 red, 16 green, 16 blue) features independent 7-bit dot correction and group-level 7-bit global brightness control. LED open detection triggers at ≤0.35 V; short detection thresholds are programmable at 70% or 90% of VCC - enabling real-time fault isolation in large-format displays without external sensing circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output channels | 48 constant-current sink outputs (16×R, 16×G, 16×B) - enables full-color RGB pixel driving per IC |
| Grayscale resolution | 16-bit (65,536 steps) - supports smooth intensity transitions and high-fidelity image rendering |
| Max sink current | 31.9 mA per channel (VCC > 3.6 V) - drives standard LEDs at full brightness without external boost |
| Data rate | 25 MHz SCLK - achieves sub-millisecond frame load times for 1920×1080+ display modules |
| GSCLK frequency | 33 MHz - enables precise 16-bit PWM timing with <±20 ns on-time error |
| Current accuracy | ±2% channel-to-channel (typ), ±5% max - ensures uniform luminance across LED arrays |
| LED fault detection | LOD threshold ≤0.35 V; LSD selectable at 70% or 90% VCC - provides deterministic failure reporting via SOUT |
Pinout & Package
Package: QFN-56 (8.0 mm × 8.0 mm, 0.5 mm pitch), thermally enhanced with exposed thermal pad requiring PCB GND connection.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SIN | Serial input | MSB-first 769-bit shift register input; initiates GS or control data load based on MSB value |
| SCLK | Shift clock | Rising-edge synchronized data capture; 25 MHz max - defines serial throughput limit |
| LAT | Latch enable | Rising edge transfers data from shift register to GS or control latch; enables display timing reset when TMGRST = 1 |
| GSCLK | Grayscale clock | Rising edge increments PWM counter; 33 MHz operation sets minimum pulse width and refresh stability |
| SOUT | Serial output | MSB of shift register; outputs status info (LOD/LSD) after LAT falling edge for daisy-chain diagnostics |
| OUTR0–OUTR15 | Red channel sinks | 16 individually controlled constant-current outputs; support parallel grouping for higher current per LED |
| OUTG0–OUTG15 | Green channel sinks | 16 dedicated green-current paths; independent DC/BC scaling enables white-point tuning |
| OUTB0–OUTB15 | Blue channel sinks | 16 blue-current outputs; matched thermal design ensures color channel consistency over temperature |
| VCC | Power supply | 3.0–5.5 V logic and analog rail; powers internal reference, shift logic, and current drivers |
| GND | Ground | Multiple pins (8, 35) - low-impedance return path critical for noise immunity in high-speed PWM |
| Thermal pad | Thermal interface | Exposed bottom pad - must be soldered to PCB GND plane for θJB = 6.5°C/W thermal performance |
Key Features
| Feature | Design Value |
|---|---|
| Integrated current setting | 3-bit maximum current (MC) control per color group replaces external Rset resistor - eliminates drift, tolerance, and layout sensitivity |
| Auto-display repeat | Hardware-based frame repetition without host intervention - reduces MCU overhead in static signage applications |
| Delay switching | Controlled turn-on sequencing prevents inrush current spikes during power-up or blanking transitions |
| UVLO default | Undervoltage lockout initializes registers to safe state (all outputs off) below 2.7 V - prevents erratic behavior during brownout |
| Low knee voltage | 0.25-V typical saturation voltage at 19.1 mA - maximizes usable LED forward voltage headroom in 5-V systems |
Applications
| LED Video Displays | Variable Message Signs (VMS) |
|---|---|
Use Scenario: Indoor/outdoor full-color LED panels with pixel pitches ≤P2.5, driven by FPGA or ASIC controllers. IC Role / Device Role / Timing Role: Primary grayscale PWM driver with per-pixel current regulation and real-time fault reporting. Use Value: 16-bit GS resolution and ±2% channel matching ensure flicker-free, high-contrast imagery across 10,000+ pixels per panel. | Use Scenario: Highway-facing dynamic message boards requiring 24/7 reliability and remote diagnostics. IC Role / Device Role / Timing Role: Fault-tolerant LED driver with LOD/LSD status reporting via daisy-chained SOUT. Use Value: Automatic LED open/short detection reduces maintenance visits by >60% and enables predictive replacement scheduling. |
| Illumination Systems | Stage & Architectural Lighting |
Use Scenario: Tunable-white and RGBW commercial lighting fixtures with DALI or DMX512 interfaces. IC Role / Device Role / Timing Role: Constant-current sink for high-CRI LED strings, managed via microcontroller SPI bridge. Use Value: 7-bit dot correction compensates for binning variance across 100+ LEDs per fixture, achieving <±0.002 u'v' chromaticity deviation. | Use Scenario: High-brightness moving-head fixtures and façade wash systems with thermal derating requirements. IC Role / Device Role / Timing Role: High-speed PWM engine supporting 120 Hz+ strobing and color morphing effects. Use Value: 33 MHz GSCLK enables sub-100 ns PWM edge placement - critical for artifact-free high-frame-rate projection mapping. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC5947RTQT | 48-channel, 12-bit GS (4096 steps), no BC/DC registers, no LOD/LSD, 16-MHz SCLK max | Lacks grayscale depth and diagnostics - suitable only for cost-sensitive, non-critical signage | Select TLC5955RTQT when 16-bit fidelity, white-point tuning, or field fault detection is required |
| IS31FL3733-QFLS4 | 48-channel, 16-bit GS, I²C interface, no LOD/LSD, 1.2-MHz bus speed, 25-mA max sink | Slower interface limits frame rate; lacks hardware timing reset and auto-refresh | Choose TLC5955RTQT for high-speed serial control, deterministic timing, and robust diagnostics in industrial displays |
Compared with TLC5947RTQT and IS31FL3733-QFLS4, the TLC5955RTQT uniquely combines 16-bit grayscale, per-channel dot correction, group-level brightness control, and hardware-accelerated LED fault detection - making it the only option qualified for mission-critical outdoor video walls and safety-signage systems.
Availability
TLC5955RTQT is available at Aetrix Electronics and suitable for LED video displays, variable message signs (VMS), and architectural illumination requiring stable component supply, long-term lifecycle support, and traceable sourcing for Class B industrial deployments.
Supply support for TLC5955RTQT 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 for industrial, automotive, and communications markets.
The TLC5955RTQT belongs to TI's high-performance LED driver product line, engineered specifically for large-format, high-brightness RGB displays demanding precision current matching, real-time diagnostics, and extended thermal operation.
FAQ
What is the maximum operating junction temperature for the TLC5955RTQT?
The TLC5955RTQT has a maximum operating junction temperature of +125°C, with recommended ambient operation from –40°C to +85°C. Its QFN-56 package achieves θJB = 6.5°C/W when the thermal pad is properly soldered to a GND plane - enabling sustained 31.9 mA output current under continuous load at 85°C ambient.
Does the TLC5955RTQT require an external current-setting resistor?
No, the TLC5955RTQT does not require an external current-setting resistor. It uses an internal reference with 3-bit maximum current (MC) control per color group (R/G/B) to set sink current ranges from 3 mA to 30 mA. This eliminates resistor tolerance drift, layout sensitivity, and potential failure modes associated with external components - a key differentiator from legacy LED drivers.
How does LED open detection (LOD) work on the TLC5955RTQT?
LED open detection (LOD) on the TLC5955RTQT monitors each output node during active drive periods and triggers when voltage exceeds 0.35 V (max). Detected faults are stored in an internal 96-bit LOD/LSD latch and read out serially via SOUT after a LAT falling edge. This allows full-panel fault mapping without additional sense circuitry or GPIO overhead.
Can the TLC5955RTQT drive LEDs with forward voltages above 5 V?
Yes, the TLC5955RTQT supports LED string voltages up to 10 V at its OUTx pins, independent of the 3.0–5.5 V VCC supply. This allows direct driving of 2–3 white/blue LEDs in series (VF ≈ 3.2–3.6 V each) without external boost converters - simplifying power architecture and improving system efficiency in high-brightness signage.
What is the function of the thermal pad on the TLC5955RTQT QFN package?
The exposed thermal pad on the TLC5955RTQT QFN-56 package is not internally connected to GND but must be externally soldered to a PCB GND plane. Doing so achieves θJB = 6.5°C/W, reducing junction temperature rise by >40% versus pad floating - essential for maintaining ±2% current accuracy and long-term reliability at full 31.9 mA load per channel.
TLC5955RTQT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 56-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Linear
- Topology:
- Shift Register
- Internal Switch(s):
- Yes
- Number of Outputs:
- 48
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 10V
- Current - Output / Channel:
- 23.9mA, 31.9mA
- Frequency:
- -
- Dimming:
- -
- Applications:
- Signage
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 56-QFN (8x8)
TLC5955RTQT FAQ
1.How can I place an order for TLC5955RTQT through Aetrix?
Please submit a Request for Quotation (RFQ) for TLC5955RTQT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TLC5955RTQT reliable?
The price and inventory of TLC5955RTQT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLC5955RTQT is usually 5 days.
3.What payment methods are accepted for TLC5955RTQT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TLC5955RTQT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TLC5955RTQT?
TLC5955RTQT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLC5955RTQT order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TLC5955RTQT?
For technical support, including TLC5955RTQT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLC5955RTQT requirements.
6.How does Aetrix verify that TLC5955RTQT is sourced from the original manufacturer or authorized distributors?
All TLC5955RTQT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TLC5955RTQT meets industry standards.
7.What is the process for return or replacement of TLC5955RTQT?
All TLC5955RTQT units undergo pre-shipment inspection (PSI). If there is an issue with TLC5955RTQT, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TLC5955RTQT part is unused and in its original packaging.
Return procedure for TLC5955RTQT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TLC5955RTQT Tags
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