General Purpose Interface GSC INT102

24-Bit SPI Interface

This sensor interface is based on TI's LMP90100 AFE System. The interface for the INT102 is based on the SPI standard; this interface has 6 wires of which two are used for power and ground. The front end has four differential inputs. Currently, two differential inputs have been reserved for sensors, one has been reserved for either measuring an RTD or ground (when the RTD is not present), and one differential input is connected to a fixed known voltage (0.2% accuracy) for test purposes. The INT102 is designed to allow for verifying connectivity and lack of shorts in real time. A high precision, low noise, voltage regulator is used to generate a 4.096V reference voltage for the A/D; it can also be used for the reference voltage for Wheatstone bridge sensors. The interface has two programmable regulated currents available which can be used to drive RTD's or other resistive sensors. GSC can quickly customize the interface for a customer's particular needs and also help develop interface software based on modifying currently available software.