Intrusion alarm systems include motion detectors, used to catch intruders or unwanted movement in security systems. These battery powered alarms generally use Passive Infrared (PIR) sensors, which can detect position and motion. The intrusion systems generally have switch outputs, which are terminated using externally configurable end-of-line (EOL) resistors as shown in Figure 2-5.

To signal a motion detected, these modules that usually have a normally-closed outputs, release contact to signal intrusion through signals like Tamper, Alarm and so forth. Traditional normally-open OptoMOS’s being used to signal the output alarm state tend to be power hungry as the bias current needs to be compensated for a lifetime of operation across system temperature. This compensation factor can be as high as 3 to 4 times of recommended operating currents.

ISOMOS eliminates the compensation factor as there is no physical LED, and ISOM8610 can be biased with as little as 1.2mA forward current across temperature for lifetime operation. This reduces the current budget for the switches, and in turn extends the lifetime of the battery powered Intrusion detection system.