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

11/14/2011

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

Page 5 of 8

MMW Series

Single and Dual Output

4:1 Input Voltage Range

25~30 Watt DC/DC Converter

Rev C

DERATING CURVE

¡ã

0

20

40

60

80

100

-40

50

60

80

100

110

90

70

400LFM

200LFM

100LFM

Natural

convection

DESIGN & FEATURE CONSIDERATIONS

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.

Over Voltage Protection

The output over voltage clamp consists of control circuitry that is dependent on the primary regulation loop that monitors the

voltage on the output terminals. The control loop of the clamp has a higher voltage set point than the primary loop. This

provides a redundant voltage control that reduces the risk of an output over voltage. The OVP level can be found in the

protection specifications.

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. A 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 < 1.0Ω at 100KHz)

capacitor of a 33μF for the 24V input models and a 10μF for the 48V input models.

+

+Out

-Out

+Vin

-Vin

DC / DC

Converter

Load

DC Power

Source

+

-

Cin

Ambient Temperature (°C)

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