2

D

Series

Series

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Test Configurations

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.

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.

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.

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 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.

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.