Deriving 3.3V from 4-20mA loop supply : using DC-DC converter.

Manjunath Bhat

Other Parts Discussed in Thread: XTR117

Hi All,

We are planning to use XTR117 with loop supply of 14V-30V DC for one of our product.

Same time we have to generate 3.3V ( @ 10mA) from Loop supply (14V to 30V ) . I am thinking to use DC-DC converter for the same.

Having said above things, i cant use on chip regulator of XTR117 (5v) , since power wastage will be huge for low power application.

But how to connect DC-DC converter to loop supply ?

Input ( +ve and -ve / GND) terminals of the DC-DC can not be directly connected to loop supply , Is this right ?

Please share if some one has the application diagram . thanks in advance.

Regards

Manjunath

0 John Caldwell over 12 years ago

Manjunath,

My colleague, Collin Wells, addressed a similar request in this thread here:

The application diagram is as follows:

The most important aspect to consider is that all return currents must flow into the Iret pin of the XTR117 to ensure proper loop current levels.

Hope this helps!

Amplifiers forum