www.irf.com

4

AN-1204

For satellites and space borne payloads, criteria for choosing such a heat sink involve size

and weight restrictions also. So highest acceptable temperature rise should be used for

working backwards to design a heat sink.

For example, let us assume we have 35

C in space environment and we accept a

temperature rise of 25

C above this and thus design a heat sink to maintain case

temperature of 60

C. Same methodology can be followed for any other allowable

temperature rise or any other acceptable size and weight of heat sink. This is, because

heat can be transferred only by conduction and radiation in space

The Thermal Analysis of ARE28XXS-D goes into great details about power dissipation

and likely temperature rise of each power semiconductor die used in the converter, stating

margins between its rated dissipation and actual designed-in dissipation. As can be

appreciated, this margin is sufficient for guaranteeing reliable performance during its

lifetime.

4

REMOTE SENSE:

The remote sense feature helps maintain output voltage regulation at the load by correcting

for

the voltage drop along the conductors that connect the load to the converter’s output. This

feature is available only on single output model (ARE28XXS). To use this feature connect

±Sense pins directly to the load. One can use thinner gauge wires for this connection, but it is

recommended that these wires be twisted. Alternatively one can use a shielded cable with

the shield being connected to case of the converter, which can be grounded as shown in

Figure (2)

Figure (2) Remote sense feature-single model

If user decides not to make use of the Remote sense feature, it is imperative that +Sense

pin be connected to +Output and

–Sense pin be connected to –Output. This is shown in

Figure (3).