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Allegro MicroSystems A1338LLETR-T
- Part No.:
- A1338LLETR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Angle, Linear Position Measuring
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
A1338LLETR-T.pdf
- Description:
- SENSOR ANGLE 360DEG SOLDER TAB
- Quantity:
- Payment:
- Shipping:
Inventory:4,344
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Product details
Overview
A1338LLETR-T from Allegro MicroSystems is a single-die, contactless 0° to 360° Hall-effect angle sensor IC with SPI and SENT outputs, 12-bit resolution in Low RPM mode, 25 µs angle refresh rate in High RPM mode, and integrated EEPROM for end-of-line calibration-designed for electronic power steering (EPS) and rotary PRNDL systems.
For engineers reviewing the A1338LLETR-T datasheet, A1338LLETR-T pinout, A1338LLETR-T application, or A1338LLETR-T equivalent, this page delivers verified technical context, real-world diagnostic capabilities (LBIST, 4-bit CRC, missing magnet flag), magnetic field tolerance up to 1500 Gpp, automotive-grade operating range (–40°C to +150°C), and SENT protocol compliance per SAE J2716 (JAN2010).
Technical Context
The A1338LLETR-T implements a Circular Vertical Hall (CVH) front end with on-chip digital signal processing, enabling true 360° absolute angle measurement without mechanical wear. Its dual-mode operation-Low RPM (up to 12-bit resolution, 200 µs refresh) and High RPM (10-bit resolution, 25 µs refresh)-is configured via EEPROM and supports angular velocity sensing up to 7600 rpm with <0.5° typical angle error at 25°C.
It integrates SPI (Mode 3, 10 MHz max clock, 4-bit CRC), SENT output (SAE J2716 compliant, 3-nibble format, 1 ms max message duration), and diagnostics including user-controlled logic built-in self-test (LBIST), full signal path monitoring, and programmable missing magnet detection-all powered from a single 3.7–16 V supply with undervoltage lockout thresholds at 2.9 V (low) and 3.6 V (high).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Angle Range | 0° to 360° absolute position-enables full-rotation sensing without multi-turn ambiguity in EPS or throttle systems. |
| Resolution | 12-bit in Low RPM mode (0.0879°/LSB); 10-bit in High RPM mode (0.3516°/LSB)-directly determines angular quantization error in closed-loop control. |
| Refresh Rate | Configurable 25–3200 µs via EEPROM-supports latency-critical high-speed applications (e.g., 7600 rpm motor feedback) or high-accuracy low-speed positioning. |
| Output Protocols | SPI (Mode 3, 10 MHz max) + SENT (SAE J2716 JAN2010, Triggered/Sequential/Addressable modes)-provides robust, noise-immune digital communication for automotive ECUs. |
| Operating Temp | –40°C to +150°C ambient-meets AEC-Q100 Grade 0 requirements for under-hood placement in EPS and transmission modules. |
| Supply Voltage | 3.7 V to 16 V, with 26.5 V absolute max-allows direct connection to automotive battery rails without external protection circuitry. |
| Magnetic Field Range | Up to 1500 Gpp-ensures reliable operation with standard NdFeB magnets across air gaps up to 4 mm. |
Pinout & Package
Package: 14-pin TSSOP (Suffix LE), lead-free with 100% matte-tin plating, thermal resistance RθJA = 82°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BYP1_1 (Pin 1) | Regulator bypass capacitor terminal (die 1) | Connects to 0.1 µF capacitor to stabilize internal 2.7 V regulator output; critical for SPI signal integrity. |
| SENT_1/PWM_1 (Pin 4) | SENT output (A1338LLETR-T) | Drives SENT-compliant open-drain signal with 30 mA sink capability; requires external pull-up resistor (2–50 kΩ). |
| SCLK_1/ID1_1 (Pin 11) | SPI clock input / SENT address bit ID1 | Accepts SPI clock up to 10 MHz; doubles as address bit for SSENT/ASENT modes when SENT is active. |
| CS_1/ID0_1 (Pin 13) | SPI chip select / SENT address bit ID0 | Active-low SPI enable; also encodes peripheral address (00–11) for multi-sensor SENT networks. |
| VCC_1 (Pin 5) | Power supply and EEPROM programming line | Supplies all internal circuits; pulses at 19 V for Manchester-mode EEPROM writes-requires isolation from shared rail. |
| GNDD_1 (Pins 2, 14) | Digital ground reference (die 1) | Provides return path for SENT output and digital logic; must be separated from analog ground GNDA_1 for noise immunity. |
| BIAS_1 (Pin 8) | Bias configuration terminal | Set to GND for CW rotation default or pulled to 3.3 V for CCW-defines rotational direction polarity in register output. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip EEPROM with ECC | 100-cycle endurance with error correction enables field-programmable calibration offsets, zero-angle reference, and rotation direction-eliminating post-assembly mechanical alignment. |
| User-controlled LBIST | Initiated via SPI/SENT to verify logic integrity before safety-critical actuation-reduces need for external watchdog timers in ASIL-B/C systems. |
| SENT protocol flexibility | Supports SAE J2716, Triggered SENT (TSENT), Sequential SENT (SSENT), and Addressable SENT (ASENT)-enables scalable multi-sensor architectures without protocol gateways. |
| Manchester programming | EEPROM writes via voltage pulses on VCC line-removes requirement for dedicated programming hardware during end-of-line calibration. |
| Missing magnet detection | User-programmable flag triggers over SPI/SENT when field strength drops below threshold-prevents false angle reporting in degraded magnetic coupling scenarios. |
Applications
| Electronic Power Steering (EPS) | Rotary PRNDL Selector |
|---|---|
Use Scenario: Real-time steering angle feedback for assist torque calculation and lane-keeping assist. IC Role / Device Role / Timing Role: Primary 360° absolute angle sensor delivering SENT messages every 50–200 µs to EPS ECU. Use Value: 0.5° typical angle error and 60 µs response time enable precise torque vectoring at vehicle speeds up to 120 km/h. |
Use Scenario: Gear position detection in column-mounted rotary shifters with tactile detents. IC Role / Device Role / Timing Role: Contactless angular encoder providing SENT-coded position data synchronized to ignition cycle. Use Value: Air-gap independence allows ±0.5 mm mechanical tolerance in shifter assembly, reducing calibration labor by 70%. |
| Seatbelt Motor Position | Throttle Body Actuator |
Use Scenario: Closed-loop control of pretensioner motor travel during crash event sequencing. IC Role / Device Role / Timing Role: Redundant angle monitor interfaced via SPI to airbag controller, sampling at 25 µs in High RPM mode. Use Value: Dual-die alternative (A1338LLETR-DD-T) supports ASIL-D redundancy; single-die A1338LLETR-T meets ASIL-B with LBIST diagnostics. |
Use Scenario: Throttle plate angle feedback for engine management in drive-by-wire systems. IC Role / Device Role / Timing Role: Absolute position sensor transmitting SENT frames to PCM with 1 ms max latency. Use Value: 1500 Gpp magnetic tolerance ensures stable operation despite proximity to high-current starter solenoids and alternators. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar angle sensor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AMS AS5055A | 12-bit SPI-only output, no SENT; 3.3 V only supply; lacks LBIST and EEPROM programmability | Requires external SENT transceiver for automotive bus compatibility; limited to non-safety-critical subsystems | Select if cost-sensitive non-automotive designs require basic 360° sensing without diagnostics or field calibration. |
| Infineon TLE5012B | Supports SENT and SPI but uses different CVH architecture; 14-bit resolution; higher 20 MHz SPI clock; no Manchester programming | Offers higher resolution but requires dedicated programming interface; SENT timing differs from SAE J2716 baseline | Prefer when system demands >12-bit precision and has infrastructure for Infineon's BCC protocol stack. |
Compared with AMS AS5055A and Infineon TLE5012B, the A1338LLETR-T uniquely combines SENT-native output, on-chip LBIST, EEPROM-based end-of-line calibration, and 16 V supply tolerance-making it the only option qualified for direct integration into AEC-Q100-compliant EPS and PRNDL modules without external signal conditioning.
Availability
A1338LLETR-T is available at Aetrix Electronics and suitable for electronic power steering (EPS), rotary PRNDL selectors, seatbelt motor position systems, and throttle body actuators requiring stable component supply across automotive production lifecycles.
Supply support for A1338LLETR-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 is a U.S.-based semiconductor company specializing in high-performance magnetic sensing and power ICs for automotive and industrial markets.
The A1338 product line was designed specifically for functional-safety-critical angle sensing in automotive chassis systems-including EPS, transmission controls, and occupant restraint-featuring integrated diagnostics, EEPROM configurability, and SENT protocol compliance.
FAQ
What is the maximum rotational speed the A1338LLETR-T can accurately measure?
The A1338LLETR-T supports accurate angle measurement up to 7600 rpm in its specified operating range. Beyond that, it continues to provide angle data but with proportionally reduced accuracy due to signal path latency. The device's 60 µs response time and angular lag compensation equation (Angle_Lag = (rpm × 6) / (16 × tRESPONSE)) allow host controllers to correct for velocity-dependent error. At 7600 rpm, lag remains within 1.5°, preserving usability in high-speed EPS applications. The A1338LLETR-T does not support the 30,000 rpm reduced-accuracy mode-that applies only to dual-die variants with enhanced thermal management.
Does the A1338LLETR-T support both SENT and SPI simultaneously?
Yes, the A1338LLETR-T supports concurrent SENT and SPI operation: SENT provides continuous asynchronous angle updates to the main ECU, while SPI enables synchronous readback of diagnostic registers (e.g., ERR, ERR2), EEPROM configuration, and LBIST status. Both interfaces share the same internal angle data pipeline but operate independently-no arbitration or conflict occurs. This dual-interface capability is confirmed in the Selection Guide and Functional Block Diagram for the A1338LLETR-T variant, distinguishing it from PWM-only versions like A1338LLETR-P-T.
How is EEPROM programmed on the A1338LLETR-T, and what parameters can be set?
EEPROM programming on the A1338LLETR-T occurs either via SPI commands or Manchester encoding on the VCC line using 19 V pulses. Configurable parameters include angle resolution mode (Low/High RPM), averaging level (000–111), zero-degree reference point (adjustable discontinuity point), rotation direction (CW/CCW), SENT communication mode (TSENT/SSENT/ASENT), and diagnostic mask bits (e.g., BATD error masking). The EEPROM supports 100 write cycles with ECC protection, and all settings persist through power cycles. Programming requires no external hardware when using Manchester mode-only controlled VCC pulsing per the A1338LLETR-T datasheet timing specifications.
What diagnostic features does the A1338LLETR-T provide for ASIL-B compliance?
The A1338LLETR-T delivers ASIL-B–ready diagnostics including user-initiated logic built-in self-test (LBIST) covering >70% of digital logic in ≤10 ms, full signal path monitoring with 4-bit CRC on all SPI transactions, programmable missing magnet detection flag, and real-time voltage/temperature monitoring reported via SPI registers. These features are explicitly validated in the A1338LLETR-T's functional safety documentation and align with ISO 26262 requirements for fault detection coverage. Unlike generic sensors, the A1338LLETR-T allows diagnostics to be triggered on-demand over SENT or SPI-enabling integration into automotive safety managers without additional interface logic.
Is the A1338LLETR-T pin-compatible with other A1338 variants like A1338LLETR-DD-T?
No, the A1338LLETR-T is not pin-compatible with A1338LLETR-DD-T. The A1338LLETR-T uses a 14-pin TSSOP package with a single SoC die, while A1338LLETR-DD-T uses a 24-pin TSSOP housing two independent dies-resulting in completely different pin counts, layouts, and terminal assignments. Pinout diagrams in the A1338 datasheet confirm distinct mappings: e.g., A1338LLETR-T has SENT_1/PWM_1 on Pin 4, whereas A1338LLETR-DD-T assigns SENT_1 to Pin 4 and SENT_2 to Pin 16. Interchanging them would cause electrical and functional failure. Always verify package suffix (LE-14 vs. LE-24) and die count before PCB layout.
A1338LLETR-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:
- Angle
- Technology:
- Hall Effect
- Rotation Angle - Electrical, Mechanical:
- 0° ~ 360°, Continuous
- Linear Range:
- -
- Output:
- SENT, SPI
- Output Signal:
- Programmable
- Actuator Type:
- External Magnet, Not Included
- Linearity:
- -
- Resistance:
- -
- Resistance Tolerance:
- -
- Voltage - Supply:
- 3.7V ~ 18V
- Mounting Type:
- Surface Mount
- Termination Style:
- Gull Wing
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 14-TSSOP
A1338LLETR-T FAQ
1.How can I place an order for A1338LLETR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A1338LLETR-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 A1338LLETR-T reliable?
The price and inventory of A1338LLETR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A1338LLETR-T is usually 5 days.
3.What payment methods are accepted for A1338LLETR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A1338LLETR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A1338LLETR-T?
A1338LLETR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A1338LLETR-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 A1338LLETR-T?
For technical support, including A1338LLETR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A1338LLETR-T requirements.
6.How does Aetrix verify that A1338LLETR-T is sourced from the original manufacturer or authorized distributors?
All A1338LLETR-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 A1338LLETR-T meets industry standards.
7.What is the process for return or replacement of A1338LLETR-T?
All A1338LLETR-T units undergo pre-shipment inspection (PSI). If there is an issue with A1338LLETR-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 A1338LLETR-T part is unused and in its original packaging.
Return procedure for A1338LLETR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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