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Allegro MicroSystems A1337LLETR-T
- Part No.:
- A1337LLETR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Angle, Linear Position Measuring
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
A1337LLETR-T.pdf
- Description:
- HIGH RESOLUTION PROGRAMMABLE ANG
- Quantity:
- Payment:
- Shipping:
Inventory:3,270
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Product details
Overview
A1337LLETR-T from Allegro MicroSystems is a single-die, contactless 0° to 360° Hall-effect angle sensor IC with dual-output capability (SPI Mode 3 and SENT), 12-bit resolution in low-RPM mode, 25 µs angle refresh rate in high-RPM mode, and integrated turns counter supporting ±1280 counts - deployed in electronic power steering (EPS) and rotary PRNDL systems.
For engineers reviewing the A1337LLETR-T datasheet, A1337LLETR-T pinout, A1337LLETR-T application, or A1337LLETR-T equivalent, this page delivers verified technical context on CVH-based angular measurement, SENT protocol modes (SAE J2716, TSENT, SSENT, ASENT), EEPROM-programmable discontinuity point, LBIST diagnostics, and low-power mode current (55 µA typical at 25°C).
Technical Context
The A1337LLETR-T implements a circular vertical Hall (CVH) front end with dual-segment analog signal path, enabling air-gap-independent 360° angle sensing without mechanical wear. Its dual-output architecture supports simultaneous SPI (4-bit CRC protected) and SENT (configurable tick time down to 0.5 µs) communication for redundancy-critical automotive subsystems.
It integrates on-chip EEPROM with ECC error correction (100 read/write cycles), user-programmable wake-up thresholds (VWAKE(HITH) = 215 mV), and programmable averaging (AVG[2:0] bits) to trade resolution (up to 12-bit) against update rate (25–3200 µs). The device operates across –40°C to +150°C and tolerates VCC up to 26.5 V for direct battery connection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Angle Range | 0° to 360° absolute position measurement using CVH technology - enables full-rotation sensing without homing or index pulses. |
| Resolution | 12-bit digital output (low-RPM mode); effective resolution 11.59 bits at B = 300 G - supports sub-degree precision in EPS and throttle control. |
| Refresh Rate | Configurable 25 µs (high-RPM) to 3200 µs (low-RPM) via EEPROM - balances latency vs. noise rejection for target RPM range. |
| Output Protocols | SPI (Mode 3, 10 MHz max clock) + SENT (J2716, TSENT, SSENT, ASENT) - allows redundant channel implementation and legacy ECU compatibility. |
| Power Consumption | 55 µA average in low-power mode (98 ms sleep, 25°C) - enables key-off operation for seatbelt motor position tracking. |
| Diagnostics | On-chip LBIST (70% coverage in 10 ms) + full-signal-path diagnostics + 4-bit SPI CRC - satisfies ASIL-B functional safety requirements. |
| Turns Counter | ±1280 count range, configurable 45° or 180° step size - maintains position history across ignition cycles without external memory. |
Pinout & Package
Package: 14-pin TSSOP (LE-14), Pb-free, 100% matte tin leadframe plating, RθJA = 82°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BYP1_1 | Analog regulator bypass (die 1) | Connects 0.1 µF capacitor to stabilize internal 2.7 V regulator output - required for stable CVH front-end biasing. |
| SENT_1 | SENT output (die 1) | Single-edge nibble transmission output compliant with SAE J2716 - drives standard 5 kΩ pull-up; supports triggered/sequential/addressable modes. |
| VCC_1 | Supply & programming input (die 1) | Accepts 3.7–16 V supply; also carries Manchester-encoded EEPROM programming pulses (18–19.5 V, 10 ms high time). |
| WAKE_1 | External wake-up trigger (die 1) | Active-high input with 215 mV threshold - detects magnet rotation >100 rpm or enables host-initiated wake from low-power mode. |
| GNDD_1 | Digital ground (pins 2 & 14) | Provides dedicated return path for SPI/SENT digital logic - must be separated from GNDA_1 to minimize noise coupling into CVH analog path. |
| CS_1/ID0_1 | SPI chip-select / SENT address bit 0 (die 1) | Active-low SPI enable; when used with SENT, defines peripheral ID for SSENT/ASENT addressing - eliminates need for separate address lines. |
| SCLK_1/ID1_1 | SPI clock / SENT address bit 1 (die 1) | Provides synchronous timing for SPI reads/writes; doubles as second address bit for SENT multi-device networks. |
| MISO_1 | SPI data output (die 1) | 3-state CMOS output with 2.7 V typical high level - delivers angle, status, and diagnostic data with 4-bit CRC protection. |
| MOSI_1 | SPI data input (die 1) | Accepts configuration commands, EEPROM writes, and diagnostic triggers - requires 25 ns setup before SCLK rising edge. |
| GNDA_1 | Analog ground (pin 3) | Reference for CVH sensor, ADC, and temperature sensor - must be routed with low-impedance path to avoid angle error drift. |
Key Features
| Feature | Design Value |
|---|---|
| CVH-based 360° sensing | Eliminates sensitivity to air-gap variation and mechanical misalignment - reduces calibration burden in EPS assembly lines. |
| Programmable discontinuity point | Allows user-defined 0° reference angle (e.g., gear tooth center) and CW/CCW rotation direction - enables custom mechanical zero alignment. |
| Transport mode | Ultralow-power state (30 µA at 150°C) for shipment and storage - prevents unintended EEPROM writes or magnetic field exposure damage. |
| Redundant dual-die option | Same footprint as A1337LLETR-DD-T (24-pin TSSOP) - permits seamless upgrade path to fault-tolerant architectures without PCB redesign. |
| Manchester programming | Writes calibration coefficients and configuration bits over VCC line - removes need for dedicated programming interface during end-of-line testing. |
Applications
| Electronic Power Steering (EPS) | Rotary PRNDL Selector |
|---|---|
Use Scenario: Real-time measurement of steering column torque and angle for assist motor control and lane-keeping feedback. IC Role / Device Role / Timing Role: Primary angle sensor providing 25 µs refresh rate and 0.5° typical error at 25°C - feeds closed-loop PID controller with minimal latency. Use Value: Enables precise torque overlay and active damping; LBIST and CRC ensure integrity under ASIL-B requirements. | Use Scenario: Detection of rotary gear position in automatic transmission shift-by-wire systems. IC Role / Device Role / Timing Role: Absolute 0°–360° position encoder with programmable 0° reference - maps mechanical detent positions to PRNDL states. Use Value: Eliminates need for optical encoders or potentiometers; turns counter retains last known position after key-off. |
| Seatbelt Motor Position | Throttle Actuator Feedback |
Use Scenario: Monitoring retractor spool rotation during pretensioner deployment and post-crash locking. IC Role / Device Role / Timing Role: Low-power mode (55 µA) operation with WAKE-triggered sampling - tracks spool motion only when belt tension changes exceed 100 rpm. Use Value: Extends vehicle battery life in key-off state while maintaining position history for crash event reconstruction. | Use Scenario: Closed-loop feedback for electronic throttle body (ETB) actuator controlling airflow in gasoline engines. IC Role / Device Role / Timing Role: High-RPM mode (7600 rpm max sensing) with 60 µs response time - synchronizes throttle plate angle with engine management system. Use Value: Reduces transient lag during tip-in/tip-out; SENT output ensures deterministic timing for ISO 26262-compliant diagnostics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar angle sensor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AS5055A-DSOM | 12-bit SPI-only output; no SENT; uses planar Hall instead of CVH; 3.3 V only; no integrated turns counter. | Lacks SENT compatibility and key-off position retention - unsuitable for redundant automotive systems requiring dual protocols. | Select only if SPI-only interface and lower cost outweigh need for SENT diagnostics and transport mode. |
| TLE5012BE1000 | 16-bit resolution; BISS-C and PWM outputs; supports 30,000 rpm sensing; includes built-in magnetic field monitor. | Higher resolution and speed but lacks EEPROM-programmable discontinuity point and Manchester programming - increases calibration complexity. | Prefer for high-speed industrial motors; avoid when production line requires VCC-line programming or custom 0° definition. |
Compared with AS5055A-DSOM and TLE5012BE1000, the A1337LLETR-T uniquely combines SENT+SPI dual output, EEPROM-configurable 0° reference, and ultralow-power transport mode - making it optimal for automotive OEMs needing ASIL-B-compliant, production-ready angle sensing with minimal test infrastructure.
Availability
A1337LLETR-T is available at Aetrix Electronics and suitable for electronic power steering (EPS), rotary PRNDL selectors, seatbelt motor position systems, and throttle actuator feedback requiring stable component supply across automotive production lifecycles.
Supply support for A1337LLETR-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 sensors and power ICs for automotive and industrial applications, headquartered in Manchester, NH, with global manufacturing and support.
The A1337 product line delivers ASIL-B-capable, contactless angle sensing for safety-critical automotive subsystems - engineered specifically for EPS, transmission controls, and throttle actuation where reliability, programmability, and dual-output redundancy are mandatory.
FAQ
What is the maximum rotational speed the A1337LLETR-T can accurately measure?
The A1337LLETR-T supports accurate angle measurement up to 7600 rpm in standard operation. At speeds beyond that - up to 30,000 rpm - it continues delivering angle data but with reduced accuracy due to increased angular lag. This behavior is documented in the operating characteristics table, where angular lag is quantified as proportional to rpm and response time (tRESPONSE = 60 µs). For applications requiring sustained >7600 rpm operation, system-level compensation using Equation 1 (AngleLag = (rpm × 6) / (16 × tRESPONSE)) is recommended.
Does the A1337LLETR-T support both SPI and SENT simultaneously?
Yes, the A1337LLETR-T supports concurrent SPI and SENT output operation. Both interfaces are independently active and driven by the same internal angle register - enabling real-time cross-checking between protocols for functional safety validation. The SPI interface provides full register access including diagnostics and EEPROM configuration, while SENT delivers time-deterministic angle updates per SAE J2716 or Allegro's proprietary TSENT/SSENT/ASENT modes. No arbitration or time-division multiplexing is required.
How is the 0° reference angle programmed on the A1337LLETR-T?
The 0° reference angle on the A1337LLETR-T is programmed via EEPROM using either the SPI interface or Manchester encoding on the VCC line. The adjustable discontinuity point allows users to define the electrical zero relative to mechanical features (e.g., gear tooth center or detent position), and store it persistently with ECC protection. This setting survives power cycles and is applied automatically at startup. Programming requires pulsing VCC to 18–19.5 V for 8–11 ms, with separation timing between pulses controlled per datasheet specifications.
What is the function of the WAKE_1 pin on the A1337LLETR-T?
The WAKE_1 pin on the A1337LLETR-T serves as an external wake-up trigger that transitions the device from low-power mode to full-power mode when magnet rotation exceeds 100 rpm or when a voltage above 215 mV is applied. It enables motion-activated sampling without continuous power draw - critical for key-off monitoring in seatbelt retractors. The pin also accepts host-generated wake signals, allowing microcontrollers to initiate diagnostics or configuration updates on demand. Its 1 MΩ input resistance minimizes loading on external circuitry.
Can the A1337LLETR-T operate directly from a 12 V automotive battery?
Yes, the A1337LLETR-T supports direct connection to a 12 V automotive battery. Its absolute maximum VCC rating is 26.5 V, and it includes undervoltage lockout (UVLO) with thresholds of 2.9 V (low) and 3.6 V (high), ensuring reliable startup and shutdown across battery voltage transients. The internal regulator stabilizes core logic and CVH front-end operation regardless of input fluctuations between 3.7 V and 16 V - eliminating need for external LDOs in most vehicle architectures.
A1337LLETR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- -
- For Measuring:
- -
- Technology:
- -
- Rotation Angle - Electrical, Mechanical:
- -
- Linear Range:
- -
- Output:
- -
- Output Signal:
- -
- Actuator Type:
- -
- Linearity:
- -
- Resistance:
- -
- Resistance Tolerance:
- -
- Voltage - Supply:
- -
- Mounting Type:
- Surface Mount
- Termination Style:
- Gull Wing
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 14-TSSOP
A1337LLETR-T FAQ
1.How can I place an order for A1337LLETR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A1337LLETR-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 A1337LLETR-T reliable?
The price and inventory of A1337LLETR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A1337LLETR-T is usually 5 days.
3.What payment methods are accepted for A1337LLETR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A1337LLETR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A1337LLETR-T?
A1337LLETR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A1337LLETR-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 A1337LLETR-T?
For technical support, including A1337LLETR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A1337LLETR-T requirements.
6.How does Aetrix verify that A1337LLETR-T is sourced from the original manufacturer or authorized distributors?
All A1337LLETR-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 A1337LLETR-T meets industry standards.
7.What is the process for return or replacement of A1337LLETR-T?
All A1337LLETR-T units undergo pre-shipment inspection (PSI). If there is an issue with A1337LLETR-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 A1337LLETR-T part is unused and in its original packaging.
Return procedure for A1337LLETR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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