Technical Reference Notes
AEO_ALO04/12/20/25x48 Series
(Single Output 8th Brick)
Basic Operation and Features (continued)
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 -VIN. On the other hand, the Negative Enable version turns unit on when
the Enable pin is at logic LOW or directly connected to -VIN. The unit turns off when the Enable pin is at Logic HIGH.
OUTPUT OVER VOLTAGE PROTECTION (OVP)
The Over Voltage Protection circuit is non-latching - auto recovery mode. The output of the converter is terminated under an
OVP fault condition (Vo > OVP threshold). The converter will attempt to restart until the fault is removed. There is a 100ms
lockout period between restart attempts.
OVER CURRENT PROTECTION (OCP)
The Over Current Protection is non-latching - auto recovery mode. The converter shuts down once the output current reaches
the OCP range. The converter will attempt to restart until the fault is removed. There is a 100ms lockout period between restart
attempts.
OVER TEMPERATURE PROTECTION (OTP)
The Over Temperature Protection circuit will shutdown the converter once the average PCB temperature (See Figure 62B for
OTP reference sense point) reaches the OTP range. This feature prevents the unit from overheating and consequently going
into thermal runaway, which may further damage the converter and the end system. Such overheating may be an effect of
operation outside the given power thermal derating conditions. Restart is possible once the temperature of the sensed location
drops to less than 110°C.
REMOTE SENSE
The remote sense pins can be used to compensate for any voltage drops (per indicated max limits) that may occur along the
connection between the output pins to the load. Pin 7 (+Sense) and Pin 5 (-Sense) should be connected to Pin 8 (+Vout) and
Pin 4 (Return) respectively at the point where regulation is desired. The combination of remote sense and trim adjust cannot
exceed 110% of VO. When output voltage is trimmed up (through remote sensing and/or trim pin), output current must be
derated and maximum output power must not be exceeded.
MODEL: AEO_ALO04/12/20/25x48 SERIES
SHEET 8 OF 26
AUGUST 25, 2005 - REVISION G
ASTEC [ Astec America, Inc ]
