My Inquiry
My Account
Allegro MicroSystems A6281EESTR-T
- Part No.:
- A6281EESTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
A6281EESTR-T.pdf
- Description:
- IC LED DRVR LIN PWM 150MA 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,998
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
A6281EESTR-T from Allegro MicroSystems is a 3-channel constant-current LED driver IC designed for RGB pixel control in large-format displays. It delivers programmable 10-bit PWM brightness (0–1023 levels per channel), 7-bit dot correction per output, and supports 10–150 mA per channel via external REXT. Its daisy-chain architecture enables single-microcontroller control of hundreds of pixels using only four logic signals - ideal for architectural lighting and scrolling marquees.
For engineers reviewing the A6281EESTR-T datasheet, A6281EESTR-T pinout, A6281EESTR-T application, or A6281EESTR-T equivalent, key selection criteria include its 3 mm × 3 mm QFN-16 package, internal 800 kHz PWM oscillator with selectable clock division (200/400/800 kHz or external), thermal shutdown (165°C), undervoltage lockout (UVLO), and buffered serial interface supporting up to 5 MHz data rates.
Technical Context
The A6281EESTR-T implements a 32-bit shift register with address-bit–controlled loading into either three 10-bit PWM counters or three 7-bit dot correction scalars. Its internal linear regulator allows VIN to connect directly to the LED supply (5.5–17 V), eliminating external bias rails - critical for distributed pixel boards.
Each output is a current-sinking channel with independent dot correction scaling (36.5–100% of REXT-set max current) and matched output-to-output current error ≤ ±7%. Buffered CO/LO/OEO/SDO outputs maintain signal integrity across daisy chains of up to 250 devices without duty-cycle skew or timing degradation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Channels | 3 independent sinking channels (OUT0, OUT1, OUT2) for RGB or monochrome LED strings |
| PWM Resolution | 10-bit per channel → 1024 intensity levels; enables >1 billion color combinations in RGB clusters |
| Dot Correction | 7-bit per channel → 128 scalar steps (36.5–100% of max current); compensates for LED binning, aging, and thermal drift |
| Output Current Range | 10–150 mA per channel, set by external REXT (e.g., 5 kΩ → 150 mA typ); stable over temperature and supply variation |
| Supply Voltage | 5.5–17 V on VIN; internal LDO allows direct connection to LED bus - no separate chip supply needed |
| Logic Interface Speed | Serial port supports up to 5 MHz clock; buffered outputs drive Cat5 UTP cables across long daisy chains |
| Thermal Protection | Thermal shutdown at 165°C (typ), with 15°C hysteresis; outputs disable while latches retain data |
Pinout & Package
Package: 16-terminal QFN (ES suffix), 3 mm × 3 mm footprint, 0.75 mm height, lead-free with 100% matte-tin plating. Exposed thermal pad (PAD) must be externally connected to both LGND and PGND for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - REXT | Current reference input | External resistor sets maximum output current (IOUT(max) = 753.12 / REXT) |
| 2 - VREG | Internal LDO bypass | Connect 1.0 μF ceramic capacitor to LGND; not an output - internal regulator node only |
| 3 - LGND | Logic ground reference | Reference for digital inputs/outputs; tied to PAD and PGND externally |
| 4 - VIN | Chip power input | Supplies internal circuitry and LDO; connect to LED supply (5.5–17 V) or to VREG for 4.75–5.5 V operation |
| 5 - CI | Serial clock input | Rising edge clocks SDI data; drives CO with 100 ns one-shot pulse to preserve chain timing |
| 6 - OEI | Output enable input | Active-low: enables/disables all three outputs simultaneously (blanking function) |
| 7 - LI | Latch input | Low-to-high transition latches 32-bit shift register contents into PWM/dot correction registers |
| 8 - SDI | Serial data input | MSB-first (bit 31 first) 32-bit stream: address bit + 3×10-bit PWM + 3×7-bit scalar + mode bits |
| 9 - OUT2 | Sinking output | Drives blue (or third-color) LED string; voltage compliance: 1–3 V (VDS(min) = 1.0 V) |
| 10 - PGND | Power ground return | High-current return path for LED currents; tied to PAD and LGND externally |
| 11 - OUT1 | Sinking output | Drives green (or second-color) LED string; matched current accuracy ±7% vs. OUT0/OUT2 |
| 12 - OUT0 | Sinking output | Drives red (or first-color) LED string; same current range and dot correction capability as others |
| 13 - SDO | Serial data output | Buffered echo of SDI bit 31 on CI falling edge - prevents race conditions in daisy chains |
| 14 - LO | Latch output | Buffered copy of LI signal; drives LI of next device in chain |
| 15 - OEO | Output enable output | Buffered copy of OEI signal; drives OEI of next device |
| 16 - CO | Clock output | 100 ns one-shot pulse synchronized to CI rising edge; maintains clock/data alignment across chain |
| PAD | Exposed thermal pad | Not internally connected; must be soldered to PCB copper plane tied to LGND/PGND for thermal dissipation (RθJA = 47 °C/W) |
Key Features
| Feature | Design Value |
|---|---|
| 3 × 10-bit PWM brightness control | Enables precise, flicker-free intensity grading across RGB LEDs - essential for high-fidelity video walls |
| 3 × 7-bit per-channel dot correction | Compensates for LED forward-voltage mismatch and aging drift without external calibration hardware |
| Daisy-chain capable with buffered I/O | CO/LO/OEO/SDO outputs drive Cat5 cables over >1 m lengths; supports up to 250 devices per chain |
| Integrated linear regulator | Eliminates need for separate 5 V rail - VIN connects directly to LED supply (5.5–17 V), reducing BOM count |
| Thermal shutdown & UVLO protection | Prevents latch-up or erroneous display during overtemperature or brownout; retains latch data during fault |
Applications
| Architectural Lighting | Large-Format Video Displays |
|---|---|
|
Use Scenario: Linear LED strips mounted on building façades, bridges, or signage with uniform color blending across meters-long runs. IC Role / Device Role / Timing Role: A6281EESTR-T acts as distributed current sink per RGB pixel, enabling synchronized PWM dimming and dot correction across thousands of nodes. Use Value: Eliminates external current-setting resistors per LED; buffered outputs maintain timing integrity over 250-device chains - reduces controller GPIO count and simplifies firmware. |
Use Scenario: High-resolution outdoor LED video walls (e.g., stadium screens) requiring consistent white point and grayscale linearity. IC Role / Device Role / Timing Role: A6281EESTR-T provides per-pixel 10-bit brightness + 7-bit dot correction, ensuring color fidelity despite LED batch variations and thermal gradients. Use Value: 1024-step PWM + calibrated current matching achieves >100:1 contrast ratio and eliminates visible banding in gradient scenes. |
| Scrolling Marquees | Colored Character Signs |
|
Use Scenario: Dynamic text-based signage (e.g., transit station info boards) with smooth horizontal scrolling and multi-color highlighting. IC Role / Device Role / Timing Role: A6281EESTR-T serves as serially addressed pixel driver, accepting real-time brightness updates via microcontroller SPI-like interface. Use Value: 5 MHz serial interface enables full-frame refresh at >120 Hz for 100-pixel chains - eliminates motion blur during fast scrolling. |
Use Scenario: Large-character alphanumeric signs (e.g., retail store logos) where red/green/blue segments require independent intensity tuning. IC Role / Device Role / Timing Role: A6281EESTR-T replaces discrete transistor/resistor drivers with integrated current regulation and per-channel dot correction. Use Value: Reduces component count by >60% vs. discrete solutions; factory-programmable dot correction ensures consistent brightness across all sign modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-channel constant-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC59283DBQR | 3-channel, 16-bit PWM, but no dot correction; requires external current-setting resistors per channel | Better resolution (65,536 levels), but lacks per-channel current trimming - unsuitable for mixed-bin RGB arrays | Choose when ultra-fine grayscale is prioritized over LED mismatch compensation |
| IS31FL3728-QFLS4-TR | 18-channel, I²C interface, integrated dot correction; smaller 4 mm × 4 mm QFN-28 package | Higher channel density and simpler bus protocol, but limited to 40 mA/channel - not suitable for high-brightness signage | Choose for compact, multi-color indicator panels where current demand < 40 mA/channel |
Compared with TLC59283DBQR and IS31FL3728-QFLS4-TR, the A6281EESTR-T uniquely balances daisy-chain scalability, per-channel dot correction, and 150 mA drive strength - making it optimal for large-pixel, high-current architectural and signage applications where thermal stability and color consistency are non-negotiable.
Availability
A6281EESTR-T is available at Aetrix Electronics and suitable for architectural lighting, large-format video displays, scrolling marquees, and colored character signage requiring stable component supply across multi-year production cycles.
Supply support for A6281EESTR-T 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
Allegro MicroSystems is a U.S.-based designer of high-performance magnetic sensing and power ICs, headquartered in Worcester, Massachusetts, with global manufacturing and support infrastructure.
The A6281 product line was developed specifically for distributed, high-reliability LED pixel control in outdoor and commercial signage - emphasizing daisy-chain robustness, thermal resilience, and per-channel current calibration.
FAQ
What is the maximum number of A6281EESTR-T devices that can be daisy-chained reliably?
The A6281EESTR-T datasheet specifies a maximum of 250 devices per daisy chain under standard PCB layout and Cat5 cabling conditions. This limit accounts for cumulative propagation delay mismatch between CI→CO and LI→LO paths, ensuring ≥20 ns setup time at the final device. For longer chains, reduce clock frequency or add repeater buffers.
How does the A6281EESTR-T handle LED forward voltage variation across channels?
The A6281EESTR-T uses a constant-current sink architecture with 1–3 V output compliance. As long as VDS remains within this range, output current remains stable regardless of LED VF differences. Dot correction registers further scale each channel's current independently to match luminance - critical for RGB white-point tuning.
Can the A6281EESTR-T operate from a 5 V supply?
Yes - but VIN must be connected externally to VREG when using 4.75–5.5 V supplies. The internal LDO requires this connection to regulate properly. Do not exceed 6 V on VREG; absolute maximum rating is 6 V. At 5 V, quiescent current is ≤5.0 mA (typ).
What is the role of the exposed thermal pad (PAD) on the A6281EESTR-T QFN package?
The exposed thermal pad on the A6281EESTR-T is not internally connected. It must be soldered to a PCB copper area tied to both LGND and PGND to provide thermal conduction and electrical grounding. Without this connection, junction temperature rises significantly - RθJA degrades from 47 °C/W to >80 °C/W, risking thermal shutdown.
How is dot correction data loaded into the A6281EESTR-T registers?
Dot correction data is loaded via the same 32-bit serial interface used for brightness data. An address bit (bit 31) determines whether incoming data targets the PWM counters (address = "0") or dot correction scalars/clock mode (address = "1"). Dot correction values are latched on the rising edge of LI, independent of PWM counter updates.
A6281EESTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Linear
- Topology:
- Shift Register
- Internal Switch(s):
- Yes
- Number of Outputs:
- 3
- Voltage - Supply (Min):
- 4.75V
- Voltage - Supply (Max):
- 17V
- Voltage - Output:
- 1V ~ 3V
- Current - Output / Channel:
- 150mA
- Frequency:
- 5MHz
- Dimming:
- PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN/MLP (3x3)
A6281EESTR-T FAQ
1.How can I place an order for A6281EESTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A6281EESTR-T 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 A6281EESTR-T reliable?
The price and inventory of A6281EESTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A6281EESTR-T is usually 5 days.
3.What payment methods are accepted for A6281EESTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A6281EESTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A6281EESTR-T?
A6281EESTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A6281EESTR-T 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 A6281EESTR-T?
For technical support, including A6281EESTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A6281EESTR-T requirements.
6.How does Aetrix verify that A6281EESTR-T is sourced from the original manufacturer or authorized distributors?
All A6281EESTR-T 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 A6281EESTR-T meets industry standards.
7.What is the process for return or replacement of A6281EESTR-T?
All A6281EESTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A6281EESTR-T, 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 A6281EESTR-T part is unused and in its original packaging.
Return procedure for A6281EESTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A6281EESTR-T Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
