Automotive camshaft speed sensor ic with true power on state ALLEGRO ATS679LSLTN LT T digital output
Product Overview
The ATS679LSL is a self-calibrating True Power-On State (TPOS) camshaft speed sensor IC. It integrates a non-rare-earth back-biasing magnet, a fully synchronous digital IC with EMC protection, and EEPROM for performance optimization and traceability. This sensor offers absolute zero-speed performance and true target state recognition at device power-on. It is designed for automotive camshaft sensing applications, providing a digital output representing the ferromagnetic target profile.
Product Attributes
- Brand: Allegro MicroSystems
- Package Type: 3-pin SIP (SL)
- Lead Plating: 100% matte-tin
- Material: Lead (Pb) free
Technical Specifications
| Characteristic | Symbol | Test Conditions | Min. | Typ. | Max. | Units | |
|---|---|---|---|---|---|---|---|
| Supply Voltage | VCC | Continuous operation, TJ < TJ(MAX) | 3.9 | 24 | V | ||
| Supply Current | ICC | 5 | 8 | 10 | mA | ||
| Output On Voltage | VOUT(SAT) | IOUT = 5 mA, Output = on state (VOUT = Low), ROUT = 50 | 500 | mV | |||
| Output Rise Time | tr | Measured 10% to 90% of VOUT; RPU = 1 k; VPU = 5 V; ROUT = 50 , COUT = 1.8 nF | 4 | s | |||
| Output Fall Time | tf | Measured 90% to 10% of VOUT; RPU = 1 k; VPU = 5 V | 2.5 | 5 | 9 | s | |
| Operational Air Gap Range | AG | TPOS guaranteed; Allegro 8X reference target | 0.5 | 2.75 | mm | ||
| Power-On Time | tPO | VCC > VCC(MIN) | 1 | ms | |||
| TPOS Mode Number of mechanical edges after power-on with output switching on TPOS threshold | 2 | 3 | edge | ||||
| Package Thermal Resistance | RJA | Single-layer PCB, with copper limited to solder pads | 134 | C/W | |||
| Operating Ambient Temperature Range | TA | -40 | 150 | C | |||
| Maximum Junction Temperature | TJ(max) | 165 | C | ||||
| Storage Temperature | Tstg | -65 | 170 | C | |||
| Part Number | Output Polarity | Packing | |||||
| ATS679LSLTN-LT-T | Low opposite target tooth | Tape and reel, 13-in. reel, 500 pieces per reel | |||||
| ATS679LSLTN-HT-T | High opposite target tooth | Tape and reel, 13-in. reel, 500 pieces per reel | |||||
Pinout Diagram
Package: SL, 3-Pin SIP
Terminal List:
- 1: VCC - Supply voltage
- 2: GND - Ground
- 3: OUT - Open drain output
Functional Description
The ATS679LSL features a self-calibrating Hall-effect sensor IC, integrated EMC protection components, and a permanent magnet. It senses magnetic field differences induced by ferromagnetic target teeth and valleys, producing a digital output signal representative of the target profile. The device incorporates advanced digital temperature compensation and a voltage regulator for undervoltage lockout and supply noise rejection. Output polarity is selectable (Low or High opposite target teeth).
Operating Modes
- TPOS Mode: Initial state after power-on, determined by a fixed-gauss TPOS threshold. Remains for at least two edges before transitioning to running mode.
- Calibration Mode: Uses threshold-based switching with continuous update to capture all teeth and valleys correctly before transitioning to running mode.
- Running Mode: Uses threshold-based switching with conventional or internal hysteresis for optimized output switching accuracy.
Power Derating
The device must be operated below the maximum junction temperature (TJ(max)). Power dissipation (PD) can be estimated using PD = VIN IIN, T = PD RJA, and TJ = TA + T. The Package Thermal Resistance (RJA) is a key factor in heat dissipation. Calculations are provided to determine maximum allowable power levels and operating voltages at specific ambient temperatures and thermal resistances.
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