Description
The MID400 is an optically isolated AC line−to−logic interface
device. It is packaged in an 8−lead plastic DIP. The AC line voltage is
monitored by two back−to−back GaAs LED diodes in series with an
external resistor. A high gain detector circuit senses the LED current
and drives the output gate to a logic low condition.
The MID400 has been designed solely for the use as an AC line
monitor. It is recommended for use in any AC−to−DC control
application where excellent optical isolation, solid state reliability,
TTL compatibility, small size, low power, and low frequency
operations are required.

Features
• Direct Operation from any Line Voltage with the Use of an External
Resistor
• Externally Adjustable Time Delay
• Externally Adjustable AC Voltage Sensing Level
• Logic Level Compatibility
• Safety and Regulatory Approvals:
♦ UL1577, 2,500 VACRMS for 1 Minute
♦ DIN−EN/IEC60747−5−5, 630 V Peak Working Insulation Voltage

Applications
• Monitoring of the AC/DC “Line−down” Condition
• “Closed−loop” Interface between Electromechanical Elements such
as Solenoids, Relay Contacts, Small Motors, and Microprocessors
• Time Delay Isolation Switch