IDS100 Series
Input Source Impedance
Test Configurations
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.
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 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 100uF for the 5V input devices and a 33uF
for the 12V and 24V devices.
Peak-to-Peak Output Noise Measurement Test
Use a Cout 4.7uF 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
Single Output
DC / DC
Resistive
Load
Scope
Converter
+
+Vin
DC / DC
+Out
-Vin
-Out
+
DC Power
Source
Load
Converter
Design & Feature Considerations
Remote On/Off
Cin
-
-Vin
-Out
Output Voltage Trim
Positive logic remote on/off turns the module on during a
logic high voltage on the remote on/off pin, and off during a
logic low.
Negative logic remote on/off turns the module off during a
logic low and on during a logic high.
Connecting the external resistor (Radj) between the Vadj
and +Vout pins decreases the output voltage to set the point
as defined in the following equation:
To turn the power module on and off, the user must supply
a switch to control the voltage between the on/off terminal and
the -Vin terminal.
．
．
(Rx 1200) (Vo-1.195)
VR1=
The switch can be an open collector or equivalent.
A logic low is -0.3V to 1.2V.
A logic high is 3.0V to 5.0V.
．
．
(Rx 1.195) -[1200 (Vo-1.195)]
IDS101 and IDS121 ==>Rx=2130[
Output Voltage range is 1.8-3.3VDC.
IDS112 and IDS122==>Rx=3840[
Output Voltage range is 3.0-5.0VDC.
The maximum sink current at on/off terminal during a logic
low is -100 uA.
The maximum allowable leakage current of the switch at
on/off terminal (3.0 to 5.0V) is 50uA.
+
+Vin
+Out
Overcurrent Protection
DC Power
Fuse
Load
Radj
Source
To provide protection in a fault (output overload) condition,
the unit is equipped with internal current limiting circuitry and
can endure current limiting for an unlimited duration. At the
point of current-limit inception, the unit shifts from voltage
control to current control. The unit operates normally once the
output current is brought back into its specified range.
-
-Vin
-Out
Vadj
On/Off
Thermal Considerations
Output Ripple Reduction
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 ambient temperature must be kept below 70°C.
The derating curves are determined from measurements
obtained in an experimental apparatus.
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 22uF
capacitors at the output.
Position of air velocity
Air Flow
50mm / 2in
probe and thermocouple
15mm / 0.6in
DUT
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