ELM365
Security System Controller
Description
The ELM365 provides all of the logic necessary
for a complete security system in an 8 pin package.
The circuit is capable of monitoring two normally
closed input loops and one normally open panic
circuit, provides a constant level and a pulsing alarm
output, and the logic to drive a status LED.
Internal timers are provided for alarm blocking
during zone entry and exit as well as circuit
resetting, should alarms go unacknowledged.
Debouncing of all of the inputs is also provided
internally, to allow for the direct interfacing to
mechanical switches.
Due to the digital techniques employed, no
external support components are required for any of
the timing functions, resulting in considerable cost
savings over other designs.
Features
• Low power CMOS design - typically 1mA at 5V
• Wide supply range - 3.0 to 5.5 volt operation
• Simultaneous monitoring of three circuits
• 45 second delay for entry and exit
• Automatic reset of alarm outputs after 5 minutes
• Status LED output driver
• High current drive outputs - up to 25 mA
• Panic input for instant triggering of the alarm
Connection Diagram
PDIP and SOIC
(top view)
Applications
V
DD
1
2
3
4
8
7
6
5
V
SS
DLoop
ILoop
LED
•
•
•
•
Home or cottage security systems
Auto or RV security systems
Individual zone monitoring in a multizone system
High or low limit warning alarms
OutP
OutC
panic
Block Diagram
V
DD
DLoop
7
V
DD
ILoop
6
45 sec
Delay
45 sec
PowerUp
Alarm
Latch
fast
slow
LED
Flasher
5
LED
V
DD
panic
4
Alarm
Latch
1.5s on
0.5s off
3
OutC
5 min
Reset
2
OutP
ELM365DSB
Elm Electronics – Circuits for the Hobbyist
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