An integrated, two-channel, proximity and touch sensor IC the MAX1441 for automotive passive-entry and user-control systems is from Maxim Integrated Products. This standalone device reduces system size and cost. It features low-power operation of less than 100µA at 14V, long-range detection, integrated power regulation, over-voltage and reverse-voltage protections, and spread-spectrum anti jamming technology. There is an embedded MAXQ microcontroller. The systems employ an 8bit, general-purpose microcontrollers with ADCs and external discrete components. Alternately, they use devices with sensing algorithms that are not user programmable, which prevents the inclusion of user-defined functionality. The device combines sensitivity detection circuits with a MAXQ microcontroller, power and protection functions, and interface I/O. This integrated solution requires five passive components to complete the capacitive sensing circuit. It features active guard architecture to shield the sense electrodes from unwanted sources without adding parasitic capacitance; spread-spectrum modulation to reduce electromagnetic emissions and susceptibility; and memory resources.
