Technical Reference Notes

ALQ40/50 Series

(Open Frame Single Output Quarter Brick)

MODEL: ALQ50 SERIES

SHEET 8 OF 16

APRIL 21, 2003 - REVISION A (PRELIMINARY)

+Vin

-Vin

Enable

-Vout

+Vout

-Sense

+Sense

Vadj

Rload

Radj_up

Figure 3. External resistor configuration to increase the outputs

+Vin

-Vin

Enable

-Vout

+Vout

-Sense

+Sense

Vadj

Rload

Radj_down

Figure 4. External resistor configuration to increase the outputs

Basic Operation and Features

INPUT UNDER VOLTAGE LOCKOUT

To prevent any instability to the converter, which may affect the end system, the ALQ50 series have been designed to turn-on

34 VDC.

OUTPUT VOLTAGE ADJUST/TRIM

The converter comes with a TRIM pin (PIN 6), which is used to adjust the output by as much as 90% to 110% of its set point.

This is achieved by connecting an external resistor as described below.

should be connected between TRIM PIN (Pin6) and

+SENSE PIN (Pin 7). Please refer to Equation (1) for the

required external resistance and output adjust

relationship.

3.3V/2.5V/1.8V

Equation (1a):

1.2V

Equation (1b):

should be connected between TRIM PIN (Pin 6) and

-SENSE PIN (Pin 5). Please refer to Equation (2) for the

required external resistance and output adjust

relationship.

Equation (2)

Radj_up

5.1 Vo 100

∆%

+

(

)

⋅

1.225

∆%

⋅

510

∆%

−

10.2

−









k

Ω

⋅

Radj_up

5.1 Vo 100

∆%

+

(

)

⋅

0.6

∆%

⋅

510

∆%

−

10.2

−









k

Ω

⋅

Radj_down

510

∆%

10.2

−









k

Ω

⋅