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Allegro MicroSystems A6279EA-T
- Part No.:
- A6279EA-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
A6279EA-T.pdf
- Description:
- IC LED DRVR LINEAR 75.5MA 24DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,741
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Product details
Overview
A6279EA-T from Allegro MicroSystems is a 16-channel serial-input constant-current LED sink driver with open-LED detection, Schmitt-trigger inputs, and thermal shutdown protection. It operates from 3.0–5.5 V logic supply, delivers up to 90 mA per output (set via external REXT), and supports 25 MHz serial data rates for driving alphanumeric or segment-based LED displays.
For engineers reviewing the A6279EA-T datasheet, A6279EA-T pinout, A6279EA-T application, or A6279EA-T equivalent, this device is selected for high-reliability LED display systems requiring fault diagnostics, low-noise digital interfacing, and stable current regulation across temperature and supply variation.
Technical Context
The A6279EA-T integrates a CMOS shift register, parallel latches, and 16 NPN constant-current sink drivers in a single BiCMOS IC. Its open-LED detection circuit monitors VCE on each output against a 0.30 V threshold and reports faults via SERIAL DATA OUT during dedicated test mode.
It features internal UVLO (2.15–2.85 V trip range), thermal shutdown at 165 °C with 15 °C hysteresis, and 20 ns output staggering delay to reduce ground bounce and EMI. All logic inputs include Schmitt-triggering for noise immunity, and OUTPUT ENABLE is active-low with 40 ns setup time.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Channels | 16 independent constant-current sink outputs for LED anode-to-VLED connections |
| Max Output Current | 90 mA per channel (typical at VCE = 0.7 V, REXT = 225 Ω); user-adjustable via single external resistor |
| Logic Supply Range | 3.0–5.5 V - compatible with both 3.3 V and 5 V microcontroller interfaces without level shifting |
| Serial Data Rate | Up to 25 MHz - enables fast refresh of large LED arrays with minimal host processor overhead |
| Open-LED Detection | Hardware-level fault reporting via SERIAL DATA OUT; detects VCE < 0.30 V on enabled outputs |
| Operating Temp | –40 °C to +85 °C ambient - qualified for industrial and commercial display environments |
| Thermal Shutdown | Triggers at 165 °C junction temperature; recovers after 15 °C hysteresis - protects against sustained overloads |
Pinout & Package
Package: 24-pin DIP (Type A), Pb-free with 100% matte tin-plated leadframe, 0.300" wide body, through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | GND | Common reference for logic and power grounds; must be low-impedance connection to minimize noise coupling |
| 2 | SERIAL DATA IN | CMOS-compatible serial input; data shifted on rising clock edge; Schmitt-triggered for noise immunity |
| 3 | CLOCK | Rising-edge-triggered shift register clock; minimum pulse width 20 ns; max frequency limited by staggering delay |
| 4 | LATCH ENABLE | Active-high strobe; transfers shift register contents to output latches; Schmitt-triggered |
| 5–20 | OUT0–OUT15 | NPN sink outputs; each delivers user-defined constant current to LED cathodes; open-LED detect enabled |
| 21 | OUTPUT ENABLE | Active-low global output control; disables all sinks when high; 40 ns setup time required before clock |
| 22 | SERIAL DATA OUT | CMOS-level output; cascades data to next device or returns OCD error bits during test mode |
| 23 | REXT | Reference terminal for external current-setting resistor; sets identical current for all 16 outputs |
| 24 | LOGIC SUPPLY (VDD) | 3.0–5.5 V supply for internal logic, shift register, latches, and control circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Constant-current sink outputs | 16 channels with ±6% matching between outputs; current set by single REXT, stable over VLED and temperature |
| Open-LED detection | Dedicated hardware circuitry that identifies open-circuit faults and reports them as serial bitstream via SDO pin |
| Output staggering delay | 20 ns delay between consecutive outputs reduces simultaneous switching noise and peak ground current |
| Integrated protection | UVLO prevents erratic behavior during brownout; thermal shutdown disables outputs at 165 °C without latch reset |
| Schmitt-trigger inputs | All digital inputs (SDI, CLOCK, LE, OE) have 200–400 mV hysteresis - rejects <10 ns noise spikes |
Applications
| Industrial Panel Displays | Point-of-Sale Terminals |
|---|---|
|
Use Scenario: Driving 16-segment alphanumeric displays in factory HMIs where reliability and fault visibility are critical. IC Role / Device Role / Timing Role: Serial-to-parallel LED driver with integrated open-circuit diagnostics and current regulation. Use Value: Eliminates need for external current-limiting resistors and discrete fault monitoring circuits - reduces BOM count and PCB area. |
Use Scenario: Controlling multi-digit LED displays in retail checkout systems exposed to variable ambient temperatures. IC Role / Device Role / Timing Role: Constant-current sink driver with thermal shutdown and UVLO for robust operation during power cycling. Use Value: Maintains consistent LED brightness across –40 °C to +85 °C while preventing display corruption during voltage dips. |
| Transportation Annunciators | Medical Equipment Status Panels |
|
Use Scenario: Illuminating status indicators in rail or bus dashboards where vibration and EMI are concerns. IC Role / Device Role / Timing Role: Low-noise LED driver with staggered outputs and Schmitt-triggered inputs for EMC resilience. Use Value: Reduces ground bounce-induced flicker and false alarms by limiting simultaneous output transitions. |
Use Scenario: Powering diagnostic LEDs on patient monitors requiring certified fault-detection capability. IC Role / Device Role / Timing Role: Open-LED detection-enabled driver supporting IEC 62304 safety requirements for failure reporting. Use Value: Enables automatic logging of LED failures without firmware polling - simplifies compliance testing and field maintenance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC59283DBQR | 16-channel constant-current sink; no open-LED detection; 3–5.5 V supply; max 120 mA/channel | Lacks hardware-level fault reporting; requires external monitoring or firmware polling for open-circuit detection | Select when higher drive current is needed and diagnostic capability is handled at system level |
| MAX7219CWG+ | 8-digit/64-LED driver with SPI interface; includes scan control, brightness DAC, and decode logic | Integrated display controller architecture; not pin-compatible; targets multiplexed 7-segment displays | Select for compact 7-segment applications where built-in digit scanning and brightness control reduce MCU load |
Compared with TLC59283DBQR and MAX7219CWG+, the A6279EA-T uniquely combines 16-channel constant-current sinking, hardware open-LED detection, and DIP packaging for legacy board upgrades - offering diagnostic capability without added components or protocol complexity.
Availability
A6279EA-T is available at Aetrix Electronics and suitable for industrial panel displays, point-of-sale terminals, transportation annunciators, and medical equipment status panels requiring stable component supply and long-term obsolescence management.
Supply support for A6279EA-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 designs high-performance magnetic sensing and power ICs for automotive, industrial, and consumer applications, with expertise in integrated analog/mixed-signal solutions.
The A6279 belongs to Allegro's constant-current LED driver product line, engineered specifically for reliable, low-noise, fault-aware LED display systems in harsh or safety-critical environments.
FAQ
What is the maximum output current per channel for the A6279EA-T?
The A6279EA-T delivers up to 90 mA per output channel under typical conditions (VCE = 0.7 V, REXT = 225 Ω). Current is precisely set by an external resistor connected to the REXT pin and remains stable across variations in VLED, temperature, and supply voltage. The A6279EA-T datasheet specifies ±6% matching between any two outputs at the same VCE.
Does the A6279EA-T support open-LED detection, and how is it implemented?
Yes, the A6279EA-T includes hardware-based open-LED detection that monitors VCE on each enabled output. When VCE falls below 0.30 V - indicating an open circuit - the corresponding bit in the shift register is set to 0. These fault bits are read out serially via the SERIAL DATA OUT pin during dedicated LED OCD test mode, enabling real-time diagnostics without host software intervention.
What package type is used for the A6279EA-T, and what are its key mechanical features?
The A6279EA-T uses a 24-pin DIP (Type A) package: 0.300" wide, through-hole mount, Pb-free with 100% matte tin-plated leadframe. It conforms to JEDEC MS-001 BE standard, features a 2.54 mm pin pitch, and includes a #1 pin indicator notch. This package supports legacy board designs and provides robust thermal performance with RθJA = 26 °C/W on a 4-layer JEDEC board.
How does the A6279EA-T handle power supply fluctuations or brownout conditions?
The A6279EA-T incorporates an internal undervoltage lockout (UVLO) circuit that disables all outputs when VDD drops below 2.15–2.85 V (depending on direction of transition). Upon recovery, internal registers and latches reset to zero, ensuring predictable startup behavior. This prevents corrupted display states during power-up or brownout events - a critical feature for industrial and medical applications.
Can multiple A6279EA-T devices be cascaded, and what is required for daisy-chaining?
Yes, multiple A6279EA-T devices can be cascaded using the SERIAL DATA OUT (SDO) pin of one device connected to the SERIAL DATA IN (SDI) pin of the next. The shift register propagates data with 30 ns propagation delay (tP(DO)). No additional control signals are needed - LATCH ENABLE and OUTPUT ENABLE remain common across the chain, enabling synchronized updates and global blanking for large LED arrays.
A6279EA-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 24-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Linear
- Topology:
- Shift Register
- Internal Switch(s):
- Yes
- Number of Outputs:
- 16
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 75.5mA
- Frequency:
- 25MHz
- Dimming:
- -
- Applications:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 24-DIP
A6279EA-T FAQ
1.How can I place an order for A6279EA-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A6279EA-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 A6279EA-T reliable?
The price and inventory of A6279EA-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A6279EA-T is usually 5 days.
3.What payment methods are accepted for A6279EA-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A6279EA-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A6279EA-T?
A6279EA-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A6279EA-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 A6279EA-T?
For technical support, including A6279EA-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A6279EA-T requirements.
6.How does Aetrix verify that A6279EA-T is sourced from the original manufacturer or authorized distributors?
All A6279EA-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 A6279EA-T meets industry standards.
7.What is the process for return or replacement of A6279EA-T?
All A6279EA-T units undergo pre-shipment inspection (PSI). If there is an issue with A6279EA-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 A6279EA-T part is unused and in its original packaging.
Return procedure for A6279EA-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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