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Allegro MicroSystems A1321ELHLT
- Part No.:
- A1321ELHLT
- Manufacturer:
- Allegro MicroSystems
- Category:
- Linear, Compass (ICs)
- Package:
- SOT-23W
- Datasheet:
-
A1321ELHLT.pdf
- Description:
- SENSOR HALL EFFECT ANALOG SOT23W
- Quantity:
- Payment:
- Shipping:
Inventory:2,640
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Product details
Overview
A1321ELHLT from Allegro MicroSystems is a ratiometric linear Hall-effect sensor IC optimized for high-temperature automotive and industrial position sensing. It delivers 5.000 mV/G sensitivity, rail-to-rail output voltage (0.2 V to 4.7 V), and stable quiescent output of 2.5 V at 5 V supply across –40 °C to +85 °C ambient. Its BiCMOS monolithic design integrates Hall element, dynamic offset cancellation, and temperature-compensated amplifier for precise analog magnetic field measurement in throttle, pedal, and suspension systems.
For engineers reviewing the A1321ELHLT datasheet, A1321ELHLT pinout, A1321ELHLT application, or A1321ELHLT equivalent, this page provides verified technical context, validated pin functions, real-world use cases, and confirmed alternative options aligned with Allegro's official replacement guidance and device specifications.
Technical Context
The A1321ELHLT implements a proprietary high-frequency (150 kHz) dynamic offset cancellation technique that eliminates residual offset caused by overmolding stress and thermal drift, enabling stable quiescent output over temperature cycling. Its internal gain and offset trim adjustments are performed at end-of-line, ensuring precision without external calibration.
This device uses a BiCMOS monolithic architecture integrating Hall element, high-gain amplifier, and rail-to-rail low-impedance output stage. It operates ratiometrically-both quiescent voltage and sensitivity scale linearly with supply voltage-and supports 4.5–5.5 V operation with 30 kHz bandwidth and ±1.5% linearity over full temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Sensitivity | 5.000 mV/G typical - enables high-resolution detection of small magnetic field changes in linear position feedback |
| Quiescent Output Voltage | 2.5 V at 5 V supply - precisely centered rail-to-rail output simplifies ADC interface and reduces signal conditioning needs |
| Operating Temperature | –40 °C to +85 °C - qualified for under-hood automotive environments and industrial control cabinets |
| Supply Voltage Range | 4.5 V to 5.5 V - tight regulation requirement ensures ratiometric accuracy and avoids Zener clamp activation |
| Output Bandwidth | 30 kHz - supports fast-response applications such as engine camshaft or crankshaft position tracking |
| Noise (p-p) | 40 mV - measured with 0.1 µF bypass capacitor; defines minimum detectable field change in noisy EMI environments |
| Supply Current | 5.6 mA typical - low power draw suitable for always-on vehicle subsystems with strict current budgets |
Pinout & Package
Package: 3-pin SOT-23W (LH suffix), surface-mount, Pb-free with 100% matte tin leadframe. Dimensions per Allegro DWG-802840: 2.98 × 1.49 × 1.00 mm, branded face orientation critical for magnetic field directionality.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Power supply input | Must be decoupled with 0.1 µF ceramic capacitor near package; clamped at 6–8.3 V to protect against transients |
| VOUT (Pin 2) | Analog output terminal | Rail-to-rail voltage output proportional to magnetic flux density; drives ≥4.7 kΩ load with ≤10 nF capacitance |
| GND (Pin 3) | Reference ground | Low-impedance return path essential for noise immunity; must connect directly to PCB ground plane near decoupling cap |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic offset cancellation | 150 kHz internal clock eliminates mechanical stress-induced offset drift, ensuring ±10 G equivalent stability over temperature |
| Ratiometric output | Both VOUT(Q) and sensitivity track supply voltage variation within ±1.5%, removing need for regulated reference |
| Temperature-stable quiescent voltage | VOUT(Q) remains within ±0.075 V of 2.5 V from –40 °C to +85 °C, enabling robust zero-point calibration |
| High-temperature reliability | Qualified to 150 °C junction temperature with 165 °C max rating; supports extended life in sealed enclosures |
| Robust EMC protection | Integrated filtering and layout-optimized die design meet automotive-level radiated and conducted immunity requirements |
Applications
| Throttle Position Sensing | Brake Pedal Position Sensing |
|---|---|
|
Use Scenario: Continuous angular measurement of accelerator pedal rotation in gasoline and hybrid powertrains. IC Role / Device Role / Timing Role: Linear Hall-effect sensor providing analog voltage output proportional to magnet displacement on rotating shaft. Use Value: 5.000 mV/G sensitivity and ±1.5% linearity enable sub-degree resolution without digital interpolation, reducing MCU processing load. |
Use Scenario: Redundant pedal travel monitoring in brake-by-wire systems requiring functional safety compliance. IC Role / Device Role / Timing Role: Primary analog position transducer feeding dual-channel ASIL-B signal chain with independent fault detection. Use Value: Stable quiescent output and ratiometric behavior ensure consistent zero-point across battery voltage fluctuations during cold cranking. |
| Steering Angle Sensing | Seat Position Adjustment |
|
Use Scenario: Non-contact rotary position feedback for electric power steering (EPS) motor control and driver assistance systems. IC Role / Device Role / Timing Role: High-bandwidth (30 kHz) magnetic field detector capturing rapid steering inputs for torque overlay algorithms. Use Value: 30 kHz bandwidth and low 40 mV p-p noise allow accurate capture of transient hand-wheel movements without aliasing or jitter. |
Use Scenario: Linear position feedback for motorized automotive seat tracks with multi-zone memory and comfort settings. IC Role / Device Role / Timing Role: Analog sensor interfacing directly to 10-bit ADC in body control module for smooth, repeatable seat positioning. Use Value: Rail-to-rail output swing (0.2–4.7 V) maximizes ADC utilization and improves position resolution by >20% vs. limited-range alternatives. |
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 |
|---|---|---|---|
| A1324LLHLX-T | Same LH package, higher temp grade (–40 °C to +150 °C), identical 5.000 mV/G sensitivity, but discontinued status differs: A1324LLHLX-T entered Last Time Buy earlier than A1321ELHLT-T | Valid for new designs requiring extended temperature range; not drop-in due to different temperature qualification and obsolescence timeline | Select only if legacy A1321ELHLT-T stock is exhausted and system validation permits +150 °C operation |
| A1322LLHLT-T | Same LH package and –40 °C to +150 °C rating, but lower 3.125 mV/G sensitivity and higher noise floor (25 mV p-p); shares same dynamic offset cancellation and ratiometric architecture | Suitable where reduced sensitivity improves dynamic range in high-field environments (e.g., transmission gear position) | Use when magnetic air gap is larger or field strength exceeds A1321ELHLT's optimal range; requires recalibration of signal chain gain |
Compared with A1321ELHLT, A1324LLHLX-T offers extended temperature capability but carries earlier obsolescence risk, while A1322LLHLT-T trades sensitivity for wider operating range and lower noise-neither is pin-compatible nor functionally identical, requiring board-level and firmware adaptations.
Availability
A1321ELHLT is available at Aetrix Electronics and suitable for throttle position sensing, brake pedal monitoring, and steering angle feedback requiring stable component supply in legacy automotive production programs.
Supply support for A1321ELHLT 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 environments, emphasizing temperature stability, ratiometric accuracy, and solid-state reliability over mechanical potentiometers.
FAQ
What is the operating temperature range of the A1321ELHLT?
The A1321ELHLT is rated for ambient temperatures from –40 °C to +85 °C. Its junction temperature can reach up to 165 °C, and thermal derating curves confirm reliable operation at full specification within this ambient range when mounted on a 2-layer PCB with thermal vias. The A1321ELHLT does not support the extended –40 °C to +150 °C range offered by the LLHLT variants.
Is the A1321ELHLT still in production?
No-the A1321ELHLT is a discontinued product. Allegro officially designated it as "Not for New Design" effective January 31, 2011, with no samples available. While limited legacy stock may exist, Aetrix Electronics advises against new designs using the A1321ELHLT and recommends evaluating A1324LLHLX-T or newer Allegro Hall-effect families for long-term supply assurance.
What is the pin configuration and package type of the A1321ELHLT?
The A1321ELHLT uses a 3-pin SOT-23W (LH) surface-mount package with pin 1 = VCC, pin 2 = VOUT, and pin 3 = GND. The branded face must face the magnet for proper polarity response, and the active Hall element lies 0.28 mm below the top surface. This matches Allegro's standard LH footprint per drawing 802840.
How does the ratiometric behavior of the A1321ELHLT affect system design?
The A1321ELHLT's ratiometric output means both its quiescent voltage (2.5 V at 5 V supply) and sensitivity (5.000 mV/G) scale linearly with supply voltage-so a 4.5 V supply yields ~2.25 V quiescent and ~4.5 mV/G sensitivity. This eliminates need for a separate voltage reference but requires the ADC reference to track VCC or use ratio-metric sampling to preserve accuracy.
What magnetic field polarity produces increasing output voltage on the A1321ELHLT?
A south-pole magnetic field applied perpendicular to the branded face of the A1321ELHLT increases the output voltage from its quiescent value toward VCC. Conversely, a north pole decreases the output toward GND. This polarity response is fixed and defined in the A1321ELHLT datasheet; reversing magnet orientation flips the transfer function and must be accounted for in mechanical mounting and software interpretation.
A1321ELHLT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- SOT-23W
- Packaging:
- Tape & Reel (TR)
- 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:
- SOT-23W
- Mounting Type:
- Surface Mount
A1321ELHLT FAQ
1.How can I place an order for A1321ELHLT through Aetrix?
Please submit a Request for Quotation (RFQ) for A1321ELHLT 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 A1321ELHLT reliable?
The price and inventory of A1321ELHLT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A1321ELHLT is usually 5 days.
3.What payment methods are accepted for A1321ELHLT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A1321ELHLT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A1321ELHLT?
A1321ELHLT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A1321ELHLT 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 A1321ELHLT?
For technical support, including A1321ELHLT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A1321ELHLT requirements.
6.How does Aetrix verify that A1321ELHLT is sourced from the original manufacturer or authorized distributors?
All A1321ELHLT 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 A1321ELHLT meets industry standards.
7.What is the process for return or replacement of A1321ELHLT?
All A1321ELHLT units undergo pre-shipment inspection (PSI). If there is an issue with A1321ELHLT, 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 A1321ELHLT part is unused and in its original packaging.
Return procedure for A1321ELHLT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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