Technical Reference Notes
AEO_ALO40/35/30/20/10x48 Series
(Single Output 8
th
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 33-36 VDC. Likewise, it has also been programmed to turn-off when V
IN
drops down to 31-34 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.
To
INCREASE
the output, external R
adj_up
resistor 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.
Equation (1a): 1.5V to 12V
5.1
×
Voset
×
(
100
+ ∆%
)
510
Radj_up
=
−
−
10.2
∆%
1.225
× ∆%
Equation (1b): 1.2V
Radj_up
=
ΚΩ
5.1
×
Voset
×
(
100
+ ∆%
)
510
−
−
10.2
0.6
× ∆%
∆%
Figure 3. External resistor configuration to increase the o/p.
ΚΩ
To
DECREASE
the output, external R
adj_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.
Equation (2):
Radj_down
510
−
10.2
⋅
kΩ
∆%
Figure 4. External resistor configuration to decrease the o/p.
Where:
∆%
= percent change in output voltage
OUTPUT ENABLE
The converter comes with an Enable pin (PIN 2), which is primarily used to turn ON/OFF the converter. Both a Positive (no “N”
suffix required) and a Negative (suffix “N” required) Enable Logic options are being offered. Please refer to Table 2 for the Part
Numbering Scheme.
For Positive Enable, the converter is turned on when the Enable pin is at logic HIGH or left open. The unit turns off when the
Enable pin is at logic LOW or directly connected to -V
IN
. On the other hand, the Negative Enable version turns unit on when the
Enable pin is at logic LOW or directly connected to -V
IN
. The unit turns off when the Enable pin is at Logic HIGH.
MODEL: AEO40x48 / ALO40x48 SERIES
JUNE 24, 2005 - REVISION B
SHEET 7 OF 30
ASTEC [ Astec America, Inc ]
