Designed to interface with a PIR sensor, the LS6511 mixed-signal, silicon-gate IC is claimed to be a reliable, cost-effective intrusion detection module for security systems. The device incorporates a two-stage differential amplifier for direct interface with the outputs of a PIR sensor. Gain and bandwidth are controlled by an external RC network, enabling application-specific customization. The amplifier outputs are processed by a window comparator and digital filter. Other features include mode select for single pulse/dual, pulse/concurrent pulse detection, an output duration timer, 5V shunt regulator, and undervoltage detection. Two complimentary outputs are provided for direct drive of a relay or LED. In either a 14-pin DIP or 14-pin SOIC, the interface device costs $0.85 each/10,000.