32
Hazardous area
Safe
 are
a
6.2.3  MTL5523 - Solenoid Alarm driver
Single channel, with line-fault detection, IIC 
The MTL5523 interface controls an on/off device in a hazardous area using a volt-free contact 
or logic signal in the safe area, and is suitable for driving loads such as solenoids. Line-Fault 
Detection (LFD) operates independently of the output state and is signalled by a safe-area, 
solid-state switch output which, when a field line is open or short-circuited, becomes de-
energised.  Earth-fault detection can be provided by connecting an MTL4220 earth leakage 
detector to terminal 3.
6
5
4
3
2
1
7
8
9
10
11
12
13
14
Solenoid, alarm 
or other IS device
+
–
Vs–
Vs+
20 to 35V dc
+
–
LFD
+
‡
‡ link to reverse output phase
Control
Terminal Function
1 Output –ve
2 Output +ve
7 Line fault signal -ve
8 Phase reversal link
9 Phase reversal link
10 Line fault signal +ve
11 Control –ve
12 Control +ve 
13 Supply –ve
14 Supply +ve 
 
Figure 6.12: 
Top label  
for MTL5523