
4
Test Configurations
+Out
-Out
+Vin
-Vin
DC / DC
Converter
Load
Battery
+
Lin
+
Cin
To Oscilloscope
Current
Probe
Input Reflected-Ripple Current Test Setup
Input reflected-ripple current is measured with an inductor
Lin (4.7uH) and Cin (220uF, ESR < 1.0
at 100 KHz) to
simulate source impedance. Capacitor Cin is to offset
possible battery impedance. Current ripple is measured at
the input terminals of the module and measurement
bandwidth is 0-500 KHz.
Peak-to-Peak Output Noise Measurement
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. A Cout of 0.47uF ceramic capacitor is placed
between the terminals shown below.
+Out
-Out
+Vin
-Vin
Single Output
DC / DC
Converter
Resistive
Load
Scope
Copper Strip
Cout
+Out
-Out
+Vin
-Vin
Dual Output
DC / DC
Converter
Resistive
Load
Scope
Copper Strip
Cout
Com.
Scope
Cout
Design & Feature Considerations
The DIHW3000 circuit block diagrams are shown in
Figures 5 and 6.
PFM
Isolation
Ref.Amp
LC
Filter
+Vin
-Vin
-Vo
+Vo
Figure 5
: Block diagram of DIHW3000 single output
modules.
+Vo
PFM
Isolation
Ref.Amp
LC
Filter
+Vin
-Vin
Com.
-Vo
Figure 6:
Block diagram of DIHW3000 dual output
modules
Input Source Impedance
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.
+
+Out
-Out
+Vin
-Vin
DC / DC
Converter
Load
DC Power
Source
+
-
Cin
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.
Capacitor mounted close to the input of 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 10uF for the 12V input devices, a 4.7 uF for the 24V
and a 2.2uF for the 48V devices.