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Allegro MicroSystems A1321EUA
- Part No.:
- A1321EUA
- Manufacturer:
- Allegro MicroSystems
- Category:
- Linear, Compass (ICs)
- Package:
- 3-SSIP
- Datasheet:
-
A1321EUA.pdf
- Description:
- SENSOR HALL EFFECT ANALOG 3SIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,310
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Product details
Overview
A1321EUA from Allegro MicroSystems is a ratiometric linear Hall-effect sensor IC in a 3-pin SIP (Single In-line Package) for high-temperature automotive and industrial position sensing. It delivers 5.0 mV/G sensitivity, 4.5–5.5 V supply operation, rail-to-rail output, and ±10 G equivalent quiescent voltage drift over –40°C to +85°C ambient range - used in throttle pedal and brake position feedback systems.
For engineers reviewing the A1321EUA datasheet, A1321EUA pinout, A1321EUA application, or A1321EUA equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation value, and two confirmed alternative parts with functional and selection guidance.
Technical Context
The A1321EUA integrates a Hall element, temperature-compensated amplifier, and rail-to-rail output stage on a single BiCMOS die. Its proprietary dynamic offset cancellation uses a 150 kHz internal clock to suppress thermal stress and molding-induced offset drift, enabling stable quiescent output voltage across temperature cycling.
It operates ratiometrically: quiescent output is precisely 50% of VCC, and sensitivity scales linearly with supply voltage. Output bandwidth is 30 kHz, supporting fast magnetic field tracking in rotating or linear motion detection where analog signal fidelity and thermal stability are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Sensitivity | 5.000 mV/G typical - enables precise analog position resolution down to ±0.2 G at 5 V supply |
| Quiescent Output Voltage | 2.5 V ±75 mV at 25°C - ratiometric to VCC, ensuring consistent zero-field reference across supply variation |
| Supply Voltage Range | 4.5–5.5 V - compatible with standard 5 V automotive and industrial rails without external regulation |
| Operating Temperature | –40°C to +85°C ambient - qualified for under-hood and factory automation environments |
| Output Bandwidth | 30 kHz - supports real-time response to mechanical motion up to ~300 Hz mechanical frequency |
| Supply Current | 5.6–8 mA - low power draw suitable for always-on sensing nodes with limited thermal budget |
| Output Noise (pk-pk) | 40 mV max with 0.1 μF bypass - defines minimum detectable field change in noisy EMI environments |
Pinout & Package
Package: 3-pin SIP (Single In-line Package), lead-free, matte tin plated leadframe. Through-hole mounting with 2.54 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC | Power supply input | Connects to regulated 4.5–5.5 V rail; includes internal Zener clamp (6–8.3 V) for transient protection |
| GND | Ground reference | Return path for supply current and output load; must be low-impedance to minimize noise coupling |
| VOUT | Analog output | Rail-to-rail voltage output proportional to magnetic flux density; drives ≥4.7 kΩ load directly |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic offset cancellation | 150 kHz clocked technique eliminates thermal stress and overmolding drift - ensures <±10 G equivalent quiescent shift over full temperature range |
| Ratiometric rail-to-rail output | Output scales with VCC and swings from near 0 V to near VCC - simplifies ADC interfacing and removes need for external reference |
| Temperature-stable sensitivity | ±1.5% ratiometric drift over VCC and ±2% long-term drift after cycling - maintains calibration integrity in thermal-cycling applications |
| Robust EMC protection | Integrated filtering and layout-optimized die design - meets automotive-level immunity without external RC networks |
| BiCMOS monolithic integration | Hall element + amplifier + output stage on one die - eliminates interconnect noise and gain mismatch common in hybrid solutions |
Applications
| Throttle Position Sensing | Brake Pedal Position Feedback |
|---|---|
Use Scenario: Measures angular displacement of accelerator pedal via magnet attached to rotating lever arm. IC Role / Device Role / Timing Role: Linear Hall-effect sensor providing analog voltage output proportional to pedal angle. Use Value: 5.0 mV/G sensitivity and ±1.5% ratiometric linearity enable sub-degree angular resolution with factory-trimmed zero-point stability. |
Use Scenario: Detects linear travel of hydraulic brake master cylinder rod using axial magnet movement. IC Role / Device Role / Timing Role: Analog magnetic field transducer converting mechanical stroke into voltage signal for ECU interpretation. Use Value: Rail-to-rail output and 30 kHz bandwidth support fast-response braking control with minimal latency and no external level-shifting. |
| Industrial Valve Actuator Monitoring | Rotary Encoder Zero-Crossing Reference |
Use Scenario: Monitors linear extension of pneumatic valve stem in process control systems operating at 85°C ambient. IC Role / Device Role / Timing Role: High-temperature-stable analog sensor feeding PLC analog input module. Use Value: –40°C to +85°C operation and ±10 G quiescent drift ensure repeatable zero-position detection across thermal cycles without recalibration. |
Use Scenario: Provides index pulse reference for incremental rotary encoders by detecting magnet passage at fixed angular position. IC Role / Device Role / Timing Role: Magnetic zero-reference detector generating clean analog threshold-crossing signal. Use Value: 40 mV pk-pk noise floor and 150 kHz internal clock enable reliable edge detection even in electrically noisy motor drive cabinets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar linear Hall-effect sensor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| A1324LUA-T | Same package and pinout; higher temp rating (–40°C to +150°C); identical 5.0 mV/G sensitivity | Supports under-hood applications beyond A1321EUA's 85°C limit; requires updated thermal derating analysis | Select when new designs require extended temperature capability and long-term supply continuity |
| ACS712ELCTR-05B-T | Current sensor (not magnetic field sensor); 5 V output swing; 185 mV/A sensitivity; different transfer function | Measures conductor current, not external magnetic field - unsuitable for position sensing unless re-engineered for current-loop feedback | Only consider if application shifts from position to current monitoring; not a functional substitute for A1321EUA |
Compared with A1321EUA, A1324LUA-T offers identical functionality with extended temperature range and active production status, while ACS712ELCTR-05B-T serves a fundamentally different measurement domain - making A1324LUA-T the only viable drop-in upgrade path for legacy A1321EUA designs requiring continued sourcing.
Availability
A1321EUA is available at Aetrix Electronics and suitable for throttle position sensing, brake pedal feedback, and industrial valve actuator monitoring requiring stable component supply despite its discontinued status for new designs.
Supply support for A1321EUA 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 and power ICs for automotive and industrial markets.
The A132X family was designed specifically for contactless linear and rotary position sensing in harsh thermal environments, emphasizing ratiometric accuracy, mechanical stress immunity, and long-term calibration stability.
FAQ
What is the operating temperature range of the A1321EUA?
The A1321EUA is rated for ambient temperatures from –40°C to +85°C. This range is explicitly specified for the A1321EUA variant in the selection guide and device characteristics tables. Operation outside this range may result in parametric deviation or reliability risk, and the device is not characterized for higher ambient conditions like the A1321LLHLT-T (–40°C to +150°C).
Is the A1321EUA still in production?
No, the A1321EUA is a discontinued product. Per the datasheet status note dated October 31, 2011, it is "no longer in production" and "should not be purchased for new design applications." Samples are no longer available. Aetrix Electronics provides legacy supply support but recommends A1324LUA-T for new designs.
What does "ratiometric" mean for the A1321EUA?
For the A1321EUA, ratiometric means both quiescent output voltage and sensitivity scale linearly with supply voltage (VCC). At 5 V, VOUT(q) = 2.5 V; at 4.5 V, it is ~2.25 V. Similarly, sensitivity remains 5.0 mV/G across 4.5–5.5 V - eliminating need for external voltage references and improving system-level accuracy when VCC is regulated.
Can the A1321EUA replace the A1322EUA or A1323EUA?
No - the A1321EUA has 5.0 mV/G sensitivity, while A1322EUA is 3.125 mV/G and A1323EUA is 2.5 mV/G. These are distinct sensitivity grades within the same family. Interchanging them alters output scaling and requires full system recalibration; they are not functionally interchangeable without hardware or firmware changes.
What is the purpose of the 150 kHz internal clock in the A1321EUA?
The 150 kHz internal clock drives the dynamic offset cancellation circuit, which continuously corrects for residual offset caused by thermal stress, overmolding, and process variation. This results in <±10 G equivalent quiescent voltage drift over temperature and ensures precise recoverability after thermal cycling - a core requirement for automotive position sensors.
A1321EUA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 3-SSIP
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Technology:
- Hall Effect
- Axis:
- Single
- Output Type:
- Analog Voltage
- Sensing Range:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Supply (Max):
- 8mA
- Current - Output (Max):
- 10mA
- Resolution:
- -
- Bandwidth:
- 30kHz
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Features:
- Temperature Compensated
- Supplier Device Package:
- 3-SIP
- Mounting Type:
- Through Hole
A1321EUA FAQ
1.How can I place an order for A1321EUA through Aetrix?
Please submit a Request for Quotation (RFQ) for A1321EUA 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 A1321EUA reliable?
The price and inventory of A1321EUA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A1321EUA is usually 5 days.
3.What payment methods are accepted for A1321EUA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A1321EUA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A1321EUA?
A1321EUA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A1321EUA 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 A1321EUA?
For technical support, including A1321EUA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A1321EUA requirements.
6.How does Aetrix verify that A1321EUA is sourced from the original manufacturer or authorized distributors?
All A1321EUA 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 A1321EUA meets industry standards.
7.What is the process for return or replacement of A1321EUA?
All A1321EUA units undergo pre-shipment inspection (PSI). If there is an issue with A1321EUA, 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 A1321EUA part is unused and in its original packaging.
Return procedure for A1321EUA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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