Application Notes

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PTH/PTV Series of Wide-Output Adjust

Power Modules (3.3/5-V Input)

Remote Sense

Products with this feature incorporate an output voltage

sense pin, Vo Sense. A remote sense improves the load

regulation performance of the module by allowing it to

compensate for any ‘IR’ voltage drop between itself and

the load. An IR drop is caused by the high output current

flowing through the small amount of pin and trace resis-

tance. To use this feature simply connect the Vo Sense pin

to the Vout node, close to the load circuit (see data sheet

standard application). If not used, the Vo Sense pin can

be left open-circuit. An internal low-value resistor (15-

Ω

or less) is connected between the Vo Sense and Vout. This

ensures the output voltage remains in regulation.

With the sense pin connected, the difference between

the voltage measured directly between the Vout and GND

pins, and that measured from Vo Sense to GND, is the

amount of IR drop being compensated by the regulator.

This should be limited to a maximum of 0.3 V.

Note: The remote sense feature is not designed to compensate

for the forward drop of non-linear or frequency dependent

components that may be placed in series with the converter

output. Examples include OR-ing diodes, filter inductors,

ferrite beads, and fuses. When these components are enclosed

by the remote sense connection they are effectively placed

inside the regulation control loop, which can adversely affect

the stability of the regulator.