RND02ZGE Datasheet, PDF (9/14 Pages) Power-One – RND Series: 8-10W DC/DC Converters 38-75V Input 3.3V & 5.0V, ±12V Dual Outputs ±15V, available with trimming

Product Specifications
RND Series: 8-10W DC/DC Converters
Nov 2001
38-75V Input
3.3V & 5.0V, ±12V Dual Outputs (±15V, available with trimming)
Output Voltage Trim
Output Current Limiting
Note: For setting nominal output voltage pin 8
must be connected to pin 9.
The trim feature allows the user to adjust the
output voltage from the nominal. This can be
used to accommodate a different requirement or
to do production margin testing.
Output voltage can be adjusted by an external
resistor. If pin 8 and pin 9 are not connected
together the output will decrease to a low value.
To increase Vo a resistor should be connected
between pin 8 / 9 and pin 17 ( -Vin). To decrease
Vo, a resistor should be connected between pin 8
and 9 (NOR).
To increase Vo:
Radj = A x (B - Vd) / (Vd - Vo) kΩ
Where: Vd = Desired output voltage
Vo = Nominal output voltage.
To reduce Vo:
Radj = C x (Vo - Vd) / (Vd - D) kΩ
Where: Vd = Desired output voltage
Vo = Nominal output voltage.
Model
RND02ZGE
RND0.8ZHH
A
0.5
0.572
B
3.92
16.126
C
2.0
2.243
D
2.56
8.295
Notes:
1. When the output voltage is trimmed up, the
output power from the converter must not
exceed its maximum rating. This is
determined by measuring the output voltage
on the output pins, and multiplying it by the
output current.
2. The trim feature allows the generation of
additional standard voltages such as ±15V
from the ±12V model.
Parallel Operation
When the output is overloaded above the
maximum output current rating, the voltage will
start to reduce to maintain the output power to a
safe level. In a condition of high overload or
short-circuit where the output voltage is pulled
below approximately 30% of Vo.Nom, the unit will
enter a ‘Hiccup’ mode of operation. Under this
condition the unit will attempt to restart,
approximately every 100ms until the overload has
cleared.
Thermal Considerations
The converter is designed for natural or forced
convection cooling. The output power of the
converter is limited by the maximum case
temperature (Tc). To ensure reliable long term
operation of the converters, and to comply with
safety agency requirements, Power-One limits
maximum allowable case temperature (Tc) to
110°C (see Mechanical Drawings).
Remote Control Feature
The remote control pin functions as a normal soft
shutdown. It is referenced to the –Vin pin. With
positive logic, when the remote control pin is
pulled low, the output is turned off and the unit
goes into a very low input power mode.
An open collector switch is recommended to
control the voltage between the remote control pin
and the -Vin pin of the converter. The remote
control pin is pulled up internally, so no external
voltage source is required. The user should avoid
connecting a resistor between the remote control
pin and the +Vin pin.
The user must take care to ensure that the pin
reference for the control is connected close to the
-Vin pin. The control signal must not be
referenced ahead of EMI filtering, or remotely
from the unit. If the remote control pin is not used,
it can be left floating.
Paralleling of two converters is possible by direct
connection of the output voltage terminal pins.
The load regulation characteristic is designed to
facilitate current sharing (typically ± 20%).
5-Nov-01
Rev 1.1
www.power-one.com
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