General Description
The AS8412 is a signal processing IC designed to implement reliable, high-performance sonar intrusion detectors. It generates short 40 kHz bursts to feed an ultrasonic transducer. The resulting sonar waves are reflected on the vehicle interior and the echoes are received by another transducer. Inside the AS8412, the electrical signal is first submitted to an analog conditioning circuit, then it is digitized and processed by a DSP, whose output is analyzed by a discriminator based on fuzzy-logic techniques. Thus, true intrusion conditions can be discerned from natural phenomena and other allowable disturbances.

Key Features
• True sonar/pulse-echo operation
• Wide dynamic range
• Programmable sensitivity levels
• Self-adaptive to vehicle interiors
• Self-adaptive to temperature and environmental changes
• High sensitivity to intrusion
• Immunity to false alarms
• Detection of sabotage attempts
• Compatible with standard 40 kHz ultrasonic transducers
• No adjustments needed at factory or at field
• Few external components
• Time reference: external clock or oscillator based on crystal/ceramic resonator
• Built-in self-test
• Internal power-on-reset
• Advanced CMOS technology
• Low power consumption: 0.65 to 1.0 mA
• Operation between -40°C and +85 °C
• Available in 20-pin DIP and 20-pin SOIC package