2A-YJD&2B-YJD Series
Test Configurations
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.
Input Reflected-Ripple Current Test Setup
Input reflected-ripple current is measured with a inductor Lin (4.7uH) and Cin
(220uF, ESR < 1.0[ at 100 kHz) to simulated source impedance.
Capacitor Cin, offsets possible battery impedance.
Current ripple is measured at the input terminals of the module, measurement
bandwidth is 0-500KHz.
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.
In applications where power is supplied over long lines and output loading is
high, it may be necessary to use a capacitor on the input to insure startup.
By using a good quality low Equivalent Series Resistance (ESR < 1.0[ at 100
kHz) capacitor of a 8.2uF for the 5V input devices, a 3.3uF for the 12V input
devices and a 1.5uF for the 24V and 48V devices, capacitor mounted close to the
power module helps ensure stability of the unit.
Peak-to-Peak Output Noise Measurement Test
Use a Cout 0.47uF 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.
Output Ripple Reduction
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 that 3.3uF capacitors are used on
output.
Design & Feature Considerations
Maximum Capacitive Load
The 2A(B)-YJD series has limitation of maximum connected capacitance on
the output.
The power module may operate in current limiting mode during start-up,
affecting the ramp-up and the startup time.
The maximum capacitance can be found in the data sheet.
http://www.microdc.cn Technical Enquiries-Email:tech@microdc.cn Tel:0086-20-86000646
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