S200R Series
In applications where power is supplied over long lines and
output loading is high, it may be necessary to use a capacitor
at the input to ensure startup.
Test Configurations
Input Reflected-Ripple Current Test Setup
Capacitor mounted close to the power module helps
ensure stability of the unit, it is recommended to use a good
quality low Equivalent Series Resistance (ESR < 1.0[ at 100
KHz) capacitor of a 2.2uF for the 5V input devices, a 1.0uF for
the 12V input devices and a 0.47uF for the 24V and 48V
devices.
Input reflected-ripple current is measured with a inductor
Lin (4.7uH) and Cin (220uF, ESR < 1.0[ at 100 KHz) to
simulate source impedance.
Capacitor Cin, offsets possible battery impedance.
Current ripple is measured at the input terminals of the
module, measurement bandwidth is 0-500 KHz.
+
+Vin
DC / DC
+Out
To Oscilloscope
+Vin
+Out
+
DC Power
Source
Load
+
+
Lin
DC / DC
Converter
Converter
Current
Probe
Load
Cin
-
-Vin
-Out
Battery
Cin
-Vin
-Out
Output Ripple Reduction
Peak-to-Peak Output Noise Measurement Test
A good quality low ESR capacitor placed as close as
practicable across the load will give the best ripple and noise
performance.
To reduce output ripple, it is recommended to use 1.5uF
capacitors at the output.
Use a Cout 0.33uF ceramic capacitor.
Scope measurement should be made by using a BNC
socket, measurement bandwidth is 0-20 MHz. Position the
load between 50 mm and 75 mm from the DC/DC Converter.
+Vin
+Out
Copper Strip
Cout
+
+Vin
+Out
Single Output
DC / DC
Resistive
Load
Single Output
DC / DC
Scope
DC Power
Source
Converter
Converter
Cout
Load
-Vin
-Out
-
-Vin
-Out
Copper Strip
Cout
+Vin
+Out
Com.
-Out
Scope
Scope
+
+Vin
+Out
Dual Output
DC / DC
Resistive
Load
Dual Output
Cout
Load
DC Power
Source
DC / DC Com.
Converter
Converter
Cout
-Vin
-
-Vin
-Out
Design & Feature Considerations
Maximum Capacitive Load
Thermal Considerations
Many conditions affect the thermal performance of the
power module, such as orientation, airflow over the module
and board spacing. To avoid exceeding the maximum
temperature rating of the components inside the power
module, the case temperature must be kept below 90°C.
The derating curves are determined from measurements
obtained in an experimental apparatus.
The S200R series has limitation of maximum connected
capacitance at the output.
The power module may be operated in current limiting
mode during start-up, affecting the ramp-up and the startup
time.
For optimum performance we recommend 220uF
maximum capacitive load for dual outputs and 470uF
capacitive load for single outputs.
The maximum capacitance can be found in the data sheet.
Position of air velocity
Air Flow
50mm / 2in
Input Source Impedance
probe and thermocouple
The power module should be connected to a low
ac-impedance input source. Highly inductive source
impedances can affect the stability of the power module.
15mm / 0.6in
DUT
REV:0 2005/04
MINMAX
5