Wall Industries, Inc. 5 Watson Brook Road Exeter, NH 03833

603-778-2300 www.wallindustries.com Fax 603-778-9797

JC Series

2:1 Wide Input Range

Single and Dual Output

2 Watt DC/DC Converter

DESIGN & FEATURE CONSIDERATONS

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.

By using a good quality low Equivalent Series Resistance (ESR < 1.0Ω at 100kHz) capacitor of 8.2µF

for the 5V input devices, a 3.3µF for the 12V input devices, and a 1.5µF for the 24V and 48V devices. A

capacitor mounted close to the power module helps ensure stability of the unit.

Maximum Capacitive Load

The JC Series has a 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 “Output Voltage / Current Rating Chart.”

Over Current 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.

Thermal Considerations

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 case temperature must be kept below 90°C. The derating curves are

determined from measurements obtained in an experimental apparatus.