
UG:107
Page 23
Table 1
Module internal reference
voltages and Thevenin
resistances
External Trim (J2-1)
Output voltage can be trimmed using an optional factory-installed Trim potentiometer or with the Trim
pin (see Figure 11). The Trim potentiometer is located on the ConverterPAC™. If the Trim potentiometer
has not been ordered, the Trim pin must be used. When using the Trim pin, the Trim limits are
determined by the DC-DC converter used on the ConverterPAC. Maximum Trim ranges are 10% above
the nominal converter voltage and 50% below the nominal converter voltage (except 10, 12 and 15V
outputs which are 10% below nominal) as measured from the output studs or output connector of
the power supply.
Note:
The combined effects of module trim up, remote sense and dynamic-load step may cause the module to trip
OVP. Recovering from OVP will require cycling input power to the MegaPAC.
The Trim pin on J2 can be used to control the output voltage. It is referenced to the –SENSE pin on J2
and can be controlled by either a resistor network or an external voltage source. To increase an output
voltage above its nominal, it is necessary to increase the voltage at the Trim pin above the internal
reference voltage (V
REF
). The reverse is true to decrease an output voltage.
Note:
Converters are sometimes pretrimmed at the factory if a nonstandard output voltage is requested. Standard
voltages include 2, 3.3, 5, 10, 12, 15, 24, 28 and 48V. If using a nonstandard voltage, or if a ConverterPAC is ordered
with a Trim option, the resistor calculations will differ from those below. Please consult the factory for assistance.
Figure 11
External trim
(Remote Sense)
Load
+OUT
+SENSE
–SENSE
–OUT
Use 22 – 24AWG Twisted Pair Wires
R5
V
REF
Trim
R6
R8
R7
To Error
Amplifier
R4
R3
R2
R1
+
+
V
2
V
1
–
–
R
TH
Use 22 – 24AWG Twisted Pair Wires
Output Module
V
REF
R
TH
VE-200 / VE-J00 ≥ 3.3V
2.5V
10.0kΩ
VE-200 / VE-J00 < 3.3V
0.97V
3.88kΩ
Maxi (Pre-Defined)
1.23V
1.0kΩ
Maxi (User-Defined)
1.23V
Consult Factory