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

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

CMMMW Series

4:1 Input Voltage Ranges

18~30 Watt, Single Output

Chassis Mount DC/DC Converter

Rev A

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

Maximum Capacitive Load

The CMMMW Series has a 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. For optimum performance we

recommend 330μF maximum capacitive load for 12V and 15V outputs and 10,000μF capacitive load for 3.3V and 5V outputs.

The maximum capacitance can be found in the Output Voltage / Current Rating Chart.

TEST CONFIGURATIONS

Input Reflected-Ripple Current Test Setup

Input reflected-

ripple current is measured with an inductor Lin (4.7μH) and Cin (220μF, ESR < 1.0Ω at 100KHz) 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 ~ 500KHz.

+Out

-Out

+Vin

-Vin

DC / DC

Converter

Load

Battery

+

Lin

+

Cin

To Oscilloscope

Current

Probe