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Texas Instruments TLC5946RHBT
- Part No.:
- TLC5946RHBT
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
TLC5946RHBT.pdf
- Description:
- IC LED DRIVER LINEAR 40MA 32VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:235
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Product details
Overview
TLC5946RHBT from Texas Instruments is a 16-channel, 12-bit PWM LED driver with integrated 6-bit dot correction and constant-current sink outputs. It delivers precise grayscale control (4096 steps), per-channel brightness calibration (64-step dot correction), and supports up to 40 mA per channel with ±1% channel-to-channel current accuracy. It is used in high-fidelity LED signage requiring uniform luminance across monochrome or full-color displays.
For engineers reviewing the TLC5946RHBT datasheet, TLC5946RHBT pinout, TLC5946RHBT application, or TLC5946RHBT equivalent, key selection considerations include its QFN-32 package, 33-MHz grayscale clock capability, open-LED detection (LOD), thermal error flag (TEF), and daisy-chainable serial interface for multi-device systems.
Technical Context
The TLC5946RHBT implements dual-mode serial programming: MODE = high configures the 96-bit shift register for 6-bit dot correction data; MODE = low loads 192-bit grayscale (PWM) data into independent latches. Its internal 12-bit grayscale counter is synchronized to GSCLK (up to 33 MHz) and resets on BLANK assertion.
Each of the 16 OUTn pins functions as a constant-current sink with programmable maximum current set by a single external resistor (RIREF) connected to IREF, delivering 4–40 mA with ±2% device-to-device accuracy. Error detection includes continuous LED open detection (LOD) and thermal shutdown at ~162°C (TEF), both reported via open-drain XERR.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 16 independent constant-current sink outputs (OUT0–OUT15) |
| Grayscale resolution | 12-bit (4096 PWM steps) - enables smooth intensity gradation without visible stepping |
| Dot correction | 6-bit (64 steps) per channel - corrects LED-to-LED forward-voltage and aging variations |
| Max output current | 40 mA per channel (dc), adjustable via RIREF (1.275 kΩ–12.75 kΩ) |
| Current accuracy | ±1% (channel-to-channel), ±2% (device-to-device) - ensures display uniformity across panels |
| Supply voltage | VCC = 3.0 V to 5.5 V - compatible with standard logic and embedded power rails |
| LED voltage support | Up to 17 V at OUT pins - drives strings of multiple LEDs in series |
Pinout & Package
Package: 5 mm × 5 mm QFN-32 with exposed thermal pad (RHB). Designed for high-density PCB layouts and efficient thermal dissipation when soldered to copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 30) | Ground reference | Common return path for all currents; must be low-impedance connection to minimize noise and thermal rise |
| VCC (Pin 27) | Power supply input | 3.0–5.5 V digital and analog core supply; bypass capacitor required near pin |
| IREF (Pin 26) | Reference current setting | Connects to GND via external resistor (RIREF) to set max output current (IOLCMax = 42.5 × VIREF/RIREF) |
| SIN (Pin 2) | Serial data input | MSB-first data stream for dot correction or grayscale; Schmitt-triggered for noise immunity |
| SCLK (Pin 1) | Data shift clock | Up to 30 MHz; rising edge clocks data into internal shift register |
| XLAT (Pin 32) | Latch control | Rising edge transfers data from shift register to dot correction or grayscale latch - immediate effect on output current |
| GSCLK (Pin 24) | Grayscale timing clock | Up to 33 MHz; drives 12-bit PWM counter; determines minimum on-time resolution (tGSCLK) |
| BLANK (Pin 31) | Global output disable | High forces all OUTn off and resets grayscale counter - used for flicker-free frame blanking |
| MODE (Pin 3) | Function mode select | High = dot correction data load; Low = grayscale data load - defines shift register length (96 vs 192 bits) |
| XERR (Pin 22) | Error status output | Open-drain flag asserted low on LED open (LOD) or junction overtemperature (TEF) |
| OUT0–OUT15 (Pins 4–21) | Constant-current sinks | 16 individually controlled outputs; each sinks up to 40 mA with ±1% matching |
| XHALF (Pin 25) | Extended interface enable | High = normal operation; Low = activates extended serial protocol for faster data throughput |
| SOUT (Pin 23) | Serial data output | Daisy-chains to SIN of next device; data delayed by one SCLK cycle |
Key Features
| Feature | Design Value |
|---|---|
| Dual-mode serial interface | Single 3-wire bus (SIN/SCLK/XLAT) supports both 6-bit dot correction and 12-bit grayscale loading via MODE pin |
| Per-channel dot correction | 64-step linear adjustment compensates for LED binning, aging, and thermal drift - critical for color-matched displays |
| Integrated error detection | Real-time LOD and TEF reporting via XERR eliminates need for external monitoring circuitry in mission-critical signage |
| Four-grouped output delay | Staggered turn-on across four 4-channel groups reduces peak current demand and EMI during PWM transitions |
| Thermal-aware design | TEF threshold at +162°C (typ) with +10°C hysteresis prevents thermal runaway while maintaining safe operating margins |
Applications
| LED Signboards | Full-Color Video Walls |
|---|---|
|
Use Scenario: Outdoor alphanumeric and graphic message boards using high-brightness through-hole or SMD LEDs. IC Role / Device Role / Timing Role: Constant-current sink driver providing synchronized grayscale PWM and per-LED brightness trimming across 16-output segments. Use Value: Eliminates visible column/row brightness non-uniformity caused by LED Vf variation, enabling consistent luminance at 4096-step depth. |
Use Scenario: Modular indoor video walls composed of RGB LED cabinets with tight pixel pitch. IC Role / Device Role / Timing Role: Per-cabinet grayscale controller managing R/G/B subpixels with independent dot correction for white-point stability. Use Value: Maintains color fidelity across temperature swings and lifetime by correcting individual LED degradation via 6-bit DC registers. |
| Monochrome Display Backlighting | Industrial Panel Indicators |
|
Use Scenario: High-reliability backlight for medical or industrial HMIs requiring flicker-free, dimmable illumination. IC Role / Device Role / Timing Role: 16-channel current source driving parallel LED strings with synchronized PWM dimming and open-circuit fault detection. Use Value: Ensures zero visual flicker (via precise GSCLK-synchronized BLANK control) and failsafe operation via LOD-triggered XERR alert. |
Use Scenario: Status indicator arrays in factory automation controllers where long-term brightness consistency is mandatory. IC Role / Device Role / Timing Role: Precision current sink for discrete indicator LEDs, programmed via microcontroller SPI interface with error feedback. Use Value: Reduces BOM count by integrating current setting, PWM generation, and fault reporting - no external resistors or comparators needed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC5947RGER | 24-channel, same 12-bit PWM + 6-bit DC, but QFN-32 with different pinout and no XHALF; higher ICC4 (45 mA max) | Better suited for larger displays needing >16 channels; requires PCB redesign due to non-pin-compatible layout | Select when scaling channel count without changing firmware interface protocol |
| IS31FL3731-QFLS4-TR | 16-channel, 8-bit PWM only (no dot correction); I²C interface; built-in auto-breathing; lower max current (28 mA) | Targeted at consumer UI lighting with animation effects, not high-precision signage requiring per-LED calibration | Choose for cost-sensitive, low-complexity indicator applications where dot correction is unnecessary |
Compared with TLC5946RHBT, TLC5947RGER offers expanded channel density but lacks XHALF-based extended interface, while IS31FL3731-QFLS4-TR trades precision dot correction for simplified I²C control and integrated effects - making TLC5946RHBT optimal for industrial-grade LED uniformity-critical systems.
Availability
TLC5946RHBT is available at Aetrix Electronics and suitable for LED signboards, full-color video walls, and industrial panel indicators requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for TLC5946RHBT 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 TLC5946RHBT belongs to TI's precision LED driver product line, engineered specifically for high-brightness display systems demanding per-pixel current matching, real-time fault detection, and daisy-chain scalability.
FAQ
What is the maximum LED string voltage supported by the TLC5946RHBT?
The TLC5946RHBT supports up to 17 V at each OUT0–OUT15 pin, enabling direct drive of multi-LED series strings (e.g., 5× white LEDs @ 3.2 V VF). This rating is absolute maximum; recommended operating voltage is ≤15 V to ensure margin under transient conditions. The device itself operates from 3.0–5.5 V VCC, independent of LED string voltage.
How does the TLC5946RHBT implement dot correction and grayscale control simultaneously?
The TLC5946RHBT uses separate internal latches: 6-bit dot correction (DC) values scale the maximum current per channel, while 12-bit grayscale (GS) values determine PWM on-time duration. During operation, the actual output current is IOUTn = IOLCMax × (DCn/63) × (GSn/4095). Both registers are loaded independently via the MODE pin and share the same SIN/SCLK interface.
Can the TLC5946RHBT be daisy-chained, and what is the maximum number of devices?
Yes - the TLC5946RHBT supports seamless daisy-chaining via SOUT-to-SIN connection. Each device consumes 96 bits (dot correction) or 192 bits (grayscale) per stage. Practical limits depend on SCLK timing margins and microcontroller SPI throughput; TI validates configurations up to 16 devices in series with proper signal integrity design and termination.
What thermal management is required for the TLC5946RHBT in continuous 40-mA-per-channel operation?
In QFN-32 (RHB) package with PowerPAD soldered to ≥1 in² 2-oz copper, the TLC5946RHBT sustains 2.2 W dissipation at +85°C ambient. At full 16×40 mA load (2.56 W), junction temperature remains below +125°C if board thermal resistance is ≤25°C/W. Use thermal vias under the exposed pad and avoid enclosing the device in sealed enclosures without airflow.
Does the TLC5946RHBT require external components for basic operation?
Yes - a single resistor (RIREF) between IREF and GND sets maximum output current; 0.1-µF ceramic decoupling capacitors are required on VCC and IREF; and series 100-Ω resistors on SCLK/XLAT/BLANK are recommended for EMI suppression. No external current-setting resistors per channel are needed - all 16 outputs share the same RIREF-defined reference.
TLC5946RHBT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Linear
- Topology:
- Shift Register
- Internal Switch(s):
- Yes
- Number of Outputs:
- 16
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 17V
- Current - Output / Channel:
- 40mA
- Frequency:
- 30MHz
- Dimming:
- -
- Applications:
- Backlight, Signage
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-VQFN (5x5)
TLC5946RHBT FAQ
1.How can I place an order for TLC5946RHBT through Aetrix?
Please submit a Request for Quotation (RFQ) for TLC5946RHBT 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 TLC5946RHBT reliable?
The price and inventory of TLC5946RHBT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLC5946RHBT is usually 5 days.
3.What payment methods are accepted for TLC5946RHBT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TLC5946RHBT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TLC5946RHBT?
TLC5946RHBT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLC5946RHBT 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 TLC5946RHBT?
For technical support, including TLC5946RHBT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLC5946RHBT requirements.
6.How does Aetrix verify that TLC5946RHBT is sourced from the original manufacturer or authorized distributors?
All TLC5946RHBT 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 TLC5946RHBT meets industry standards.
7.What is the process for return or replacement of TLC5946RHBT?
All TLC5946RHBT units undergo pre-shipment inspection (PSI). If there is an issue with TLC5946RHBT, 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 TLC5946RHBT part is unused and in its original packaging.
Return procedure for TLC5946RHBT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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