INM 5500 Rev 11
45
6 .4 .4
MTL5544A/MTL5544AS - Current Repeater
Two channel, for 4/20mA passive input for HART® transmitters
The MTL5544A provides an input for separately powered 4/20mA transmitters and also allows
bi–directional transmission of HART communication signals superimposed on the 4/20mA loop
current. Alternatively, the MTL5544AS acts as a current sink for a safe-area connection rather
than driving a current into the load.
Hazardous area
Safe area
Vs–
Vs+
20 to 35V dc
+
–
Ch 2
Ch 2
Ch 1
+
–
Ch 1
4/20mA
4/20mA
6
5
4
3
2
1
7
8
9
10
11
12
13
14
I
I
I
I
MTL5544A
MTL5544AS
–
4/20mA
Load
+
Load
+
–
–
+
–
4/20mA
Load
+
Load
+
–
–
+
Terminal
Function
1
Ch1 input –ve
2
Ch1 input +ve
4
Ch2 input –ve
5
Ch2 input +ve
8
Ch2 output –ve (+ve current sink)
9
Ch2 ve (–ve current sink)
11
Ch1 output –ve (+ve current sink)
12
Ch1 ve (–ve current sink)
13
Supply –ve
14
ve
Figure 6 .23:
Top labels
for MTL5544A
& MTL5544AS
