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WALL INDUSTRIES, INC.

Rev C

FA12S15-300

(888) 597-WALL

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Page 5 of 14

Synchronization

The FA series provides synchronization of switching frequencies between multiple FA series power supplies. The synchronization

function is accomplished without the need for any added external circuitry. By tying the SYNC pin between FA modules, they will all

automatically synchronize. If synchronization is not used, the pin should be tied to –Vin.

Output Voltage Trim

The following information is provided to allow quick calculation of the trim resistor value for a desired output voltage. The general

procedure for calculating a trim resistor is as follows:

1. Determine the desired output voltage deviation %.

2. To trim down, solve for resistor value using the “Rtlow” equation.

3. To trim up, solve for resistor value using the “Rthi” equation.

4. Solved resistor values are in KΩ.

Notes:

1. Maximum trim range is ±10%. This includes remote sense drops if applicable.

2. Output current is limited to specified current when trimming down.

3. Output power is limited to specified power when trimming up.

4. Trim resistors should be placed close to the module.

5. If the trim function is not used, it is advised to leave the trim pin floating / not connected.



















2

.

10

%

510

Rtlow



























2

.

10

%

510

%

2225

.

1

%)

100

(

o

V

1

.

5

Rthi

Figure 3

Figure 4