AIF25R48_03 Datasheet, PDF (13/29 Pages) Astec America, Inc – Isolated DC/DC Converter Module

AIF25R48 Series Technical Reference Note
Output Side CNT (CNT2/CNT3) Function
Two CNT2/CNT3 logic options are available. CNT2/CNT3 can be used as shown in Fig2 with
a “Negative Logic” module. The switch is opposite with a “Positive Logic” module. CNT1
must be connected to -Vin when CNT2/CNT3 is used. And make sure that sink current of
output side CNT circuit should be less than 12mA.
Trim
Fig.2 Output Side CNT (CNT2/CNT3) Function for “Negative Logic” Module
The output voltage of the AIF25R48 series can be trimmed using the trim pin provided.
Applying a resistor to the trim pin through a voltage divider from the VB will cause the output
to increase 10% or decrease 20%. Trimming up by more than 10% of the nominal output
may activate the OVP circuit or damage the converter. Trimming down more than 20% can
cause the converter to regulate improperly. If the trim pin is not needed, it should be left
open.
DATE: May 28, 2003
Fig.3 Trim Up Circuit and Formula
MODEL : AIF25R48 SERIES
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