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Allegro MicroSystems A1321LUA
- Part No.:
- A1321LUA
- Manufacturer:
- Allegro MicroSystems
- Category:
- Linear, Compass (ICs)
- Package:
- 3-SSIP
- Datasheet:
-
A1321LUA.pdf
- Description:
- SENSOR HALL EFFECT ANALOG 3SIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,631
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Product details
Overview
A1321LUA from Allegro MicroSystems is a ratiometric linear Hall-effect sensor IC in a 3-pin SIP (Single In-line Package) for high-temperature operation up to +150°C ambient, delivering 5.000 mV/G typical sensitivity, 2.5 V quiescent output at 5 V supply, and rail-to-rail voltage output proportional to magnetic flux density. It serves as a contactless position or current sensing element in automotive throttle and brake pedal assemblies.
For engineers reviewing the A1321LUA datasheet, A1321LUA pinout, A1321LUA application, or A1321LUA equivalent, this page provides verified technical context, exact pin mapping, real-world use scenarios, and validated alternative options for legacy design continuity and obsolescence mitigation.
Technical Context
The A1321LUA integrates a BiCMOS monolithic circuit with a Hall element, temperature-compensating circuitry, high-gain amplifier, and rail-to-rail low-impedance output stage. Its proprietary dynamic offset cancellation uses a 150 kHz internal clock to suppress residual offset caused by overmolding and thermal stress.
This architecture enables stable quiescent output voltage (±10 G equivalent drift over –40°C to +150°C), precise recoverability after temperature cycling, and immunity to mechanical stress - all critical for automotive-grade linear position sensing where field accuracy and long-term stability are non-negotiable.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Sensitivity | 5.000 mV/G typical - enables high-resolution detection of small magnetic field changes in throttle position systems. |
| Quiescent Output Voltage | 2.5 V at 5 V supply - ratiometric midpoint ensures predictable zero-field reference across supply variations. |
| Operating Temperature | –40°C to +150°C ambient - qualified for under-hood automotive environments without external cooling. |
| Supply Voltage Range | 4.5 V to 5.5 V - tight regulation requirement minimizes need for external LDO in 5 V rail systems. |
| Output Bandwidth | 30 kHz - supports fast-response applications such as real-time pedal position feedback in drive-by-wire systems. |
| Supply Current | 5.6 mA typical - low power draw suitable for always-on vehicle subsystems with strict energy budgets. |
| Output Resistance | 1.5 Ω typical - low impedance drives standard 4.7 kΩ load directly without buffering. |
Pinout & Package
Package: 3-pin Single In-line Package (SIP), lead-free, matte tin plated leadframe. Pin 1 = VCC, Pin 2 = GND, Pin 3 = VOUT.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Power supply input | Accepts 4.5–5.5 V; internal Zener clamp activates above 6 V to protect against transients. |
| GND (Pin 2) | Reference ground | Common return path for supply and output; must be low-impedance to maintain noise immunity. |
| VOUT (Pin 3) | Analog voltage output | Rail-to-rail, ratiometric output proportional to magnetic field; sinks or sources up to ±1 mA. |
Key Features
| Feature | Design Value |
|---|---|
| Ratiometric rail-to-rail output | Quiescent voltage and sensitivity scale linearly with VCC - eliminates need for separate voltage reference in 5 V systems. |
| Dynamic offset cancellation | 150 kHz internal clock reduces thermal and mechanical stress-induced offset - ensures <±10 G equivalent drift over full temperature range. |
| Temperature-stable sensitivity | ±1.5% ratiometric drift over VCC and ±2% long-term drift after cycling - maintains calibration integrity in harsh thermal cycles. |
| Robust EMC protection | Integrated filtering and layout-optimized die design - meets automotive-level immunity requirements without external RC networks. |
| High-temperature qualification | Rated for 150°C ambient with 165°C max junction temperature - supports placement near engines or exhaust manifolds. |
Applications
| Automotive Throttle Position Sensing | Industrial Linear Actuator Feedback |
|---|---|
|
Use Scenario: Detecting angular displacement of throttle plate in gasoline engine management systems. IC Role / Device Role / Timing Role: Contactless analog position transducer providing continuous voltage output proportional to plate angle. Use Value: Enables precise air-fuel ratio control with no wear, hysteresis, or contact bounce - critical for emissions compliance and drivability. |
Use Scenario: Monitoring extension/retraction of hydraulic cylinders in construction equipment. IC Role / Device Role / Timing Role: Magnetic field-to-voltage converter mounted on cylinder rod with external magnet. Use Value: Delivers stable 30 kHz bandwidth signal across –40°C to +150°C ambient - eliminates need for recalibration during seasonal operation. |
| Brake Pedal Position Monitoring | Motorized Seat Position Control |
|
Use Scenario: Measuring travel distance of brake pedal for electronic stability control (ESC) activation timing. IC Role / Device Role / Timing Role: Primary analog sensor feeding ESC ECU with real-time pedal displacement data. Use Value: Ratiometric output ensures consistent response despite battery voltage sag during cranking - improves system reliability. |
Use Scenario: Tracking seat track position in premium automotive seating systems with memory presets. IC Role / Device Role / Timing Role: High-accuracy linear position sensor interfacing directly to seat control MCU ADC. Use Value: 5.000 mV/G sensitivity resolves sub-millimeter movement - enables smooth, repeatable seat positioning within ±0.5 mm tolerance. |
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 SIP package, same 5.000 mV/G sensitivity, but production status: Pre-End of Life (as of Jan 2011). | Identical pinout and electrical interface - direct replacement for new builds where A1321LUA is unavailable. | Select A1324LUA-T only if sourcing from existing inventory; not recommended for long-term production due to announced obsolescence. |
| APS12800KMA | Allegro's newer 3-pin SIP Hall sensor with 5.0 mV/G sensitivity, 30 kHz bandwidth, and extended –40°C to +150°C rating - fully qualified per AEC-Q100 Grade 0. | Includes integrated diagnostics and improved EMC performance; requires minor firmware adaptation for fault reporting. | Preferred for new designs requiring automotive qualification and lifecycle assurance beyond 2025. |
Compared with A1321LUA, A1324LUA-T offers identical functionality but carries imminent obsolescence risk, while APS12800KMA delivers enhanced diagnostics and AEC-Q100 compliance at the cost of minor system integration effort - making it the strategic upgrade path for production continuity.
Availability
A1321LUA is available at Aetrix Electronics and suitable for automotive throttle sensing, brake pedal monitoring, industrial actuator feedback, and motorized seat position control requiring stable component supply despite its discontinued status.
Supply support for A1321LUA 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 high-temperature, high-reliability linear and rotary position sensing in automotive powertrain and chassis systems - emphasizing ratiometric stability, mechanical stress immunity, and robust EMC behavior.
FAQ
Is A1321LUA still in production?
No, A1321LUA is a discontinued product. Allegro declared it Not for New Design as of January 31, 2011, with no samples available. Aetrix Electronics maintains limited legacy stock for continuity support, but new designs should migrate to A1324LUA-T or APS12800KMA. The A1321LUA datasheet remains publicly accessible for reference and validation purposes.
What is the correct pinout for A1321LUA?
The A1321LUA uses a 3-pin SIP package with Pin 1 = VCC, Pin 2 = GND, Pin 3 = VOUT. This matches the UA package drawing in the A1321-DS Rev. 23 datasheet. Do not substitute LH-package pinout (1=VCC, 2=VOUT, 3=GND); using incorrect pin assignment will cause functional failure or damage.
Can A1321LUA operate at 12 V supply?
No, A1321LUA is rated for 4.5 V to 5.5 V supply only. Applying 12 V exceeds the absolute maximum supply voltage of 8 V and risks permanent damage. Its internal Zener clamp activates above ~6 V, causing excessive current draw and thermal stress. Always regulate to 5 V ±0.5 V using an appropriate LDO or DC/DC converter.
What does "ratiometric" mean for A1321LUA?
For A1321LUA, ratiometric means both quiescent output voltage and sensitivity scale linearly with supply voltage - e.g., at 4.5 V supply, VOUT(Q) ≈ 2.25 V and sensitivity ≈ 4.5 mV/G. This eliminates need for a separate voltage reference and ensures consistent performance across normal 5 V rail tolerances without recalibration.
How does A1321LUA handle temperature variation?
A1321LUA maintains ±10 G equivalent quiescent voltage drift and ±1.5% ratiometric sensitivity drift over –40°C to +150°C, achieved via on-chip temperature-compensating circuitry and dynamic offset cancellation. Its BiCMOS design and internal gain/offset trim ensure stable output without external compensation components - critical for under-hood automotive use.
A1321LUA 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 ~ 150°C
- Grade:
- -
- Qualification:
- -
- Features:
- Temperature Compensated
- Supplier Device Package:
- 3-SIP
- Mounting Type:
- Through Hole
A1321LUA FAQ
1.How can I place an order for A1321LUA through Aetrix?
Please submit a Request for Quotation (RFQ) for A1321LUA 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 A1321LUA reliable?
The price and inventory of A1321LUA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A1321LUA is usually 5 days.
3.What payment methods are accepted for A1321LUA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A1321LUA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A1321LUA?
A1321LUA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A1321LUA 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 A1321LUA?
For technical support, including A1321LUA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A1321LUA requirements.
6.How does Aetrix verify that A1321LUA is sourced from the original manufacturer or authorized distributors?
All A1321LUA 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 A1321LUA meets industry standards.
7.What is the process for return or replacement of A1321LUA?
All A1321LUA units undergo pre-shipment inspection (PSI). If there is an issue with A1321LUA, 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 A1321LUA part is unused and in its original packaging.
Return procedure for A1321LUA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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