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

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.

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 MDHU100 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.

capacitive load for single outputs.

The maximum capacitance can be found in the data sheet.

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

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 2.2uF for the 5V input devices, a 1.0uF for

the 12V input devices and a 0.47uF for the 24V input devices.

+Out

-Out

+Vin

-Vin

Load

DC Power

Source

+

-

Cout

Single Output

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 to use 3.3uF

capacitors at the output.

MDHU100 Series

REV:5 2009/01/16

MINMAX

5

+Out

-Out

+Vin

-Vin

DC / DC

Converter

Load

Battery

+

Lin

+

Cin

To Oscilloscope

Current

Probe

+Out

-Out

+Vin

-Vin

Dual Output

DC / DC

Converter

Resistive

Load

Scope

Copper Strip

Cout

Com.

Scope

Cout

+Out

-Out

+Vin

-Vin

Single Output

DC / DC

Converter

Resistive

Load

Scope

Copper Strip

Cout

+

+Out

-Out

+Vin

-Vin

DC / DC

Converter

Load

DC Power

Source

+

-

Cin

+Out

-Out

+Vin

-Vin

Load

DC Power

Source

+

-

Cout

Com.

Dual Output

DC / DC

Converter

+Out

-Out

+Vin

-Vin

Load

DC Power

Source

+

-

Cout

Single Output

DC / DC

Converter