ASIC CONTROL CIRCUIT FOR DOWNSIZE JUVENILE SALMON ACOUSTIC TELEMETRY SYSTEM (JSATS)
An application specific integrated circuit (ASIC) for the Juvenile Salmon Acoustic Telemetry System (JSATS) is designed and implemented in a Tower-Jazz 0.18 μm process. JSATS uses small and light weight acoustic transmitters implanted within juvenile salmon to track migration of fish through facilities such as dams and locks in the Columbia River basin. Data collected by the JSATS will be used to evaluate the environmental impact of those facilities. The existing JSATS transmitter is built using discrete electrical components and has a dimension of 12mm long, 4mm high and 5mm wide with a dry weight 430mg. The tag requires surgical implantation which increases the cost and decreases salmon survival rate. In this downsize JSATS project a low power consumption ASIC is designed to control and drive the piezoelectric transducer to transmit the desired ultrasonic tag code. Part of the transmitter includes a small micro-battery with 7mAHr capacity, which is being developed by Pacific National Laboratory (PNNL) to power the downsize JSATS transmitter. The downsize JSATS transmitter will be small enough to be injected into the juvenile salmon using a gauge 9 (3mm diameter) needle. The ASIC transmits a tag using a binary phase shift key (BPSK) code. The user has full control of length of the tag code, cycles per bit, acoustic source level, and other parameters by programming the ASIC through a radio frequency (RF) link or an infrared photodiode. The ASIC also provides the option to measure temperature and insert measurement results within the tag. The ASIC has a 30 MHz crystal driver to provide a precise transmission frequency and low-power internal clocks with automatic calibration to create accurate transmission intervals. The ASIC also has the ability to hibernate for up to 6 months and then automatically begin regular transmissions. The ASIC can operate for at least 20 days when powered by the 7mAHr micro-battery and configured to transmit a 31-bit tag code with 10 cycles per bit at 153dB acoustic source level every 3 seconds. The die size of the ASIC is 800 μm by 1893 μm.