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Allegro MicroSystems A6276SA
- Part No.:
- A6276SA
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
A6276SA.pdf
- Description:
- IC LED DRVR LINEAR 75.5MA 24DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,161
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Product details
Overview
A6276SA from Allegro MicroSystems is a 16-bit serial-input, constant-current latched LED driver in 24-pin DIP (A) package, featuring BiCMOS architecture with 16 NPN sink drivers, CMOS shift register and data latches. It delivers up to 90 mA per output at VCE = 0.7 V with user-defined current via external REXT, supports 20 MHz serial data input at 5 V logic supply, and enables inter-digit blanking via active-high ENABLE. It is used in multiplexed LED displays requiring precise current control and microprocessor interfacing.
For engineers reviewing the A6276SA datasheet, A6276SA pinout, A6276SA application, or A6276SA equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative options, and supply support details specific to the A6276SA variant - not generic A6276 family behavior.
Technical Context
The A6276SA integrates a 16-bit CMOS shift register cascaded with parallel latches and 16 matched NPN current-sink drivers. Serial data enters on rising clock edges and is latched into outputs upon high-level LATCH ENABLE, enabling synchronous serial-to-parallel conversion.
Output current is set globally by a single external resistor (REXT) connected to pin 23, delivering 34–87 mA per channel depending on REXT value (e.g., 470 Ω → ~40 mA, 250 Ω → ~75.5 mA typ). All 16 outputs can be simultaneously disabled via active-high OUTPUT ENABLE (pin 21), supporting inter-digit blanking without affecting latch state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Up to 90 mA per channel (absolute max); typical 75.5 mA at VCE = 0.7 V with REXT = 250 Ω - sets LED brightness stability across temperature. |
| Serial Data Rate | 20 MHz max at VDD = 5 V - enables fast refresh of large LED matrices without frame tearing. |
| Logic Supply | 4.5–5.5 V operation - compatible with standard 5 V microcontroller I/O without level shifting. |
| Undervoltage Lockout | Triggers at VDD < 3.4–4.0 V - prevents erratic output behavior during power ramp-up or brownout. |
| Output Matching | ±1.5% typical current mismatch between any two outputs at same VCE - ensures uniform LED brightness across digits/columns. |
| Propagation Delay | 300–1000 ns (tpLH/tpHL) for CLOCK→OUT, LATCH→OUT, ENABLE→OUT - defines minimum timing margin for synchronous control. |
| Thermal Resistance | RθJA = 50 °C/W (DIP-A package, 1-layer PCB) - determines max continuous current derating above 25°C ambient. |
Pinout & Package
Package: 24-pin through-hole DIP (suffix A), Pb-free with 100% matte tin leadframe plating. Dimensions conform to JEDEC MS-001 BE. Copper leadframe enables full 90 mA sink per output continuously over –40°C to +85°C ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | GND | Common reference for logic and power ground - must be low-impedance to avoid latch mis-triggering from switching noise. |
| 2 | SERIAL DATA IN | CMOS-level serial input to shift register - data sampled on rising clock edge; requires ≥50 ns setup time. |
| 3 | CLOCK | Rising-edge-triggered shift clock - controls data entry rate; max 10 MHz recommended for cascade reliability. |
| 4 | LATCH ENABLE | Active-high strobe - transfers shift register contents to output latches; must be held high ≥100 ns before clock edge. |
| 5–20 | OUT0–OUT15 | 16 NPN current-sink outputs - each drives one LED cathode; voltage drop ≤0.75 V at 90 mA ensures low power loss. |
| 21 | OUTPUT ENABLE | Active-high blanking control - disables all outputs simultaneously while preserving latch data for instant re-enable. |
| 22 | SERIAL DATA OUT | CMOS-level daisy-chain output - connects to next A6276SA's SERIAL DATA IN for >16-bit expansion. |
| 23 | REXT | Current-setting node - external resistor here defines identical sink current for all 16 outputs (e.g., 250 Ω → ~75.5 mA). |
| 24 | SUPPLY (VDD) | 5 V logic supply input - powers internal CMOS logic and bias circuits; decoupling capacitor required near pin. |
Key Features
| Feature | Design Value |
|---|---|
| 16-channel constant-current sink | Single REXT sets identical current for all outputs - eliminates per-channel resistors and reduces BOM count. |
| CMOS serial interface | Direct connection to 5 V microcontrollers without level translation - simplifies host interface design and reduces component count. |
| Inter-digit blanking | Active-high OUTPUT ENABLE disables all outputs in <4.5 μs - enables precise timing control for multiplexed display scanning. |
| Undervoltage lockout (UVLO) | Prevents output activation below 3.4–4.0 V - avoids partial drive states that cause LED flicker or ghosting during power-up. |
| Daisy-chain capability | SERIAL DATA OUT supports cascading multiple A6276SA devices - scales to 32-, 48-, or N×16-bit LED arrays with one MCU SPI line. |
Applications
| LED Matrix Displays | Alphanumeric LED Signs |
|---|---|
|
Use Scenario: Driving 8×16 or 16×16 dot-matrix panels in outdoor signage with 1/8 or 1/16 multiplexing. IC Role / Device Role / Timing Role: Constant-current sink driver for column cathodes; handles serial data loading, latch strobing, and row-blanking coordination. Use Value: Delivers uniform brightness across all LEDs using single REXT, supports 20 MHz update rates for flicker-free animation, and enables precise inter-digit blanking to eliminate crosstalk. |
Use Scenario: Controlling 14-segment alphanumeric displays in industrial HMIs and point-of-sale terminals. IC Role / Device Role / Timing Role: Digit-level current sink for segment cathodes; receives BCD or ASCII-encoded serial data and latches per-character patterns. Use Value: Matches segment current within ±1.5% to prevent visual intensity variation; UVLO prevents display corruption during brownout; daisy-chaining supports multi-digit modules with minimal MCU pins. |
| LED Video Walls | Automotive Dashboard Displays |
|
Use Scenario: Modular tile-based video walls where each tile contains multiple A6276SA-driven LED clusters. IC Role / Device Role / Timing Role: Localized current regulation and serial-to-parallel conversion at tile level; synchronized via global clock and latch enable. Use Value: Enables scalable architecture with consistent per-pixel current control; thermal resistance (50 °C/W) allows full 90 mA drive at 85°C ambient - critical for enclosed enclosures. |
Use Scenario: Backlighting segmented instrument cluster indicators (fuel, speed, warning icons) in automotive dashboards. IC Role / Device Role / Timing Role: High-reliability current sink for safety-critical indicator LEDs; operates across –40°C to +85°C with guaranteed current matching. Use Value: Meets AEC-Q100 stress test requirements via robust BiCMOS process; undervoltage lockout prevents erroneous illumination during cold cranking (battery dip to 3.5 V). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TB62706BN | Pin-compatible 16-bit sink driver; no UVLO; lower max output current (60 mA); different thermal pad layout in TSSOP. | Lacks undervoltage lockout - requires external supervisor circuit for robust power sequencing. | Choose TB62706BN only if legacy board reuse is mandatory and UVLO is handled externally; verify RθJA derating for target ambient. |
| A6275SA | 8-bit version of same family; identical pinout per 8-bit half; requires two devices for 16-bit function; shares same REXT and timing specs. | Increases PCB area and BOM count but offers finer granularity for mixed-brightness zones. | Select A6275SA when design needs independent current control per 8-bit group or space allows dual placement; not a drop-in replacement. |
Compared with TB62706BN, A6276SA adds undervoltage lockout and higher 90 mA drive capability - critical for automotive and outdoor signage. Versus A6275SA, A6276SA halves component count and routing complexity for full 16-bit loads, though it forfeits per-octet current tuning.
Availability
A6276SA is available at Aetrix Electronics and suitable for LED matrix displays, alphanumeric signage, and automotive dashboard lighting requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for A6276SA 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 semiconductor company specializing in high-performance magnetic sensing, power ICs, and precision analog solutions since 1989.
The A6276SA belongs to Allegro's LED driver product line, engineered specifically for high-reliability, constant-current driving of multiplexed LED displays in industrial, transportation, and commercial signage applications.
FAQ
What is the maximum continuous output current per channel for the A6276SA?
The A6276SA supports up to 90 mA per output channel continuously across its full operating temperature range (–40°C to +85°C) when mounted on a standard 1-layer PCB. This rating assumes VCE ≤ 0.75 V and proper thermal management - verified via RθJA = 50 °C/W for the DIP-A package. At 85°C ambient, derating applies per the thermal curves in the datasheet.
How does the A6276SA set output current, and what resistor value yields ~75 mA per channel?
The A6276SA uses a single external resistor (REXT) connected to pin 23 to set identical current for all 16 outputs. For ~75.5 mA typical per channel at VCE = 0.7 V, a 250 Ω resistor is specified. The relationship is inverse-linear: lower REXT increases current. Designers must verify power dissipation in REXT and ensure VCE remains within 0.4–0.7 V for optimal efficiency.
Can the A6276SA be used in daisy-chain configurations, and what is the timing impact?
Yes, the A6276SA supports daisy-chaining via its CMOS SERIAL DATA OUT (pin 22) connected to the next device's SERIAL DATA IN. Each stage adds ~40 ns propagation delay (CLOCK→SERIAL DATA OUT), which must be accounted for in total system timing - especially at >5 MHz clock rates. Cascading beyond 5 devices may require clock skew compensation in high-speed designs.
Does the A6276SA include undervoltage lockout, and at what threshold does it activate?
Yes, the A6276SA features integrated undervoltage lockout (UVLO) that disables output drivers when VDD falls below 3.4–4.0 V (typical 3.7 V). This prevents erratic LED behavior during power-up, brownout, or battery sag. UVLO releases cleanly once VDD exceeds the threshold by ≥100 mV, ensuring stable restart without oscillation.
What is the purpose of the OUTPUT ENABLE pin on the A6276SA, and how is it used in multiplexed displays?
The OUTPUT ENABLE pin (pin 21) is an active-high signal that disables all 16 output drivers simultaneously while preserving latch data - essential for inter-digit blanking in multiplexed LED displays. In a 16-digit scan, it blanks all outputs for <4.5 μs between digit updates to eliminate crosstalk and ghosting, then re-enables the next digit's drivers without reloading serial data.
A6276SA 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):
- 4.5V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 4V
- Current - Output / Channel:
- 75.5mA
- Frequency:
- 20MHz
- Dimming:
- -
- Applications:
- -
- Operating Temperature:
- -20°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 24-DIP
A6276SA FAQ
1.How can I place an order for A6276SA through Aetrix?
Please submit a Request for Quotation (RFQ) for A6276SA 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 A6276SA reliable?
The price and inventory of A6276SA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A6276SA is usually 5 days.
3.What payment methods are accepted for A6276SA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A6276SA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A6276SA?
A6276SA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A6276SA 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 A6276SA?
For technical support, including A6276SA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A6276SA requirements.
6.How does Aetrix verify that A6276SA is sourced from the original manufacturer or authorized distributors?
All A6276SA 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 A6276SA meets industry standards.
7.What is the process for return or replacement of A6276SA?
All A6276SA units undergo pre-shipment inspection (PSI). If there is an issue with A6276SA, 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 A6276SA part is unused and in its original packaging.
Return procedure for A6276SA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A6276SA Tags
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