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

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

CMMM Series

2:1 Input Voltage Ranges

18~30 Watt, Single Output

Chassis Mount DC/DC Converter

Rev A

Remote On/Off

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

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 low is -1V to 1.0V.

A logic high is 2.5V to 100V.

The maximum sink current at the on/off terminal (pin 4) during a logic low is -

100μA. The maximum allowable leakage

current of the switch at the on/off terminal (pin 4) during a logic high (2.5 to 100V) is 5μA.

Output Voltage Trim

Output voltage trim allows the user to increase or decrease the output voltage set point of a module. The output voltage can

be adjusted by placing an external resistor (R) between the Trim and +Vout or –Vout terminals. By adjusting R, the output

voltage can be changed by ±10% of the nominal output voltage.

+Out

-Out

+Vin

-Vin

Trim Up

Enable

Trim

Trim Down

10K

Trim

Up/Down

A 10K, 1 or 10 turn trimpot is usually specified for continuous trimming. Trim pin may be safely left floating if it is not being

defined in the following equation:

(33 x Vout) - (30 x Vadj)

Vadj - Vout

in the following equation:

(36.667 x Vadj) - (33 x Vout)

Vout - Vadj

Vout:

Nominal Output Voltage

Vadj:

Adjusted Output Voltage

Units

VDC / K

Ω

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