ALD18 ASTEC [Astec America, Inc], ALD18 Datasheet - Page 6

• Manufacturer Part Number: ALD18
• Description: Single Output 16th Brick: 60Watts
• Manufacturer: ASTEC [Astec America, Inc]

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
is in the voltage range of 34-36 VDC. Likewise, it has also been programmed to turn-off when V
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
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 5V
Equation (1b): 1.2V
To DECREASE the output, external R
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):
Where:
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.
MODEL: ALD12/18/20/25 SERIES
AUGUST 17, 2005 – REVISION C
R adj_up
R adj_up
Radj_down
% = percent change in output voltage






5.1 Vo set
5.1 Vo set



1.225
510
0.6
%
10.2
100
100
%
%



k
%
%
adj_up
adj_down
510
510
Technical Reference Notes
%
%
resistor
ALD12/18/20/25 Series
(Single Output 16
resistor
10.2
10.2






Figure 3. External resistor configuration to increase the outputs
Figure 4. External resistor configuration to increase the outputs
-Vin
Enable
+Vin
-Vin
Enable
+Vin
th
Brick)
+Sense
+Sense
-Sense
-Sense
+Vout
+Vout
-Vout
-Vout
Vadj
Vadj
IN
drops down to 31-33.5 VDC.
Radj_down
Radj_up
SHEET 6 OF 20
Rload
Rload
IN