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

Remote On/Off

Negative logic remote on/off turns the module off during a

logic high voltage on the remote on/off pin, and on during a

logic low.

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.

The switch can be an open collector or equivalent.

A logic high is 2.9V to 15V.

A logic low is under 0.6 VDC or open circuit, drops down to

0VDC by 2mV/]

The maximum sink current at on/off terminal during a logic

low is 1 mA.

The maximum allowable leakage current of the switch at

on/off terminal =(under 0.6VDC or open circuit) is 1mA.

Maximum Capacitive Load

The MEW1000 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.

Overcurrent Protection

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 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.

MEW1000 Series

6

MINMAX

REV:3 2008/10/02

+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

Single Output

DC / DC

Converter

+Out

-Out

+Vin

-Vin

Load

DC Power

Source

+

-

Cout

Com.

Dual Output

DC / DC

Converter