Technical Reference Notes
AEO_ALO04/12/20/25x48 Series
(Single Output 8th Brick)
Basic Operation and Features
INPUT UNDER VOLTAGE LOCKOUT
To prevent any instability to the converter, which may affect the end system, the converter have been designed to turn-on once
V
IN is in the voltage range of 33 to 36VDC. Likewise, it has also been programmed to turn-off when VIN drops down to 31 to
34VDC
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.
To INCREASE the output, external Radj_up resistor
-Vout
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.
-Vin
-Sense
Vadj
Rload
Enable
+Vin
Radj_up
+Sense
+Vout
Equation (1a): 1.5V to 12V
(
)
5.1× Vo × 100 + ∆%
=
set
510
∆%
R
−
− 10.2 ΚΩ
adj_up
1.225× ∆%
Figure 3. External resistor configuration to increase the outputs
Equation (1b): 1.2V
(
)
5.1× Vo × 100 + ∆%
=
set
510
∆%
R
−
− 10.2 ΚΩ
adj_up
0.6× ∆%
To DECREASE the output, external Radj_down resistor
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.
-Vout
-Vin
-Sense
Radj_down
Rload
Vadj
+Sense
+Vout
Enable
+Vin
Equation (2):
510
∆%
Radj_down
− 10.2 ⋅kΩ
Where: ∆% = percent change in output voltage
Figure 4. External resistor configuration to increase the outputs
MODEL: AEO_ALO04/12/20/25x48 SERIES
SHEET 7 OF 26
AUGUST 25, 2005 - REVISION G
ASTEC [ Astec America, Inc ]
