Technical Reference Notes
AEH/ALH80 Series
Basic Operation and Features
(continued)
OUTPUT ENABLE
The AEH/ALH80 series comes with an Enable pin (PIN 2), which is primarily used to turn ON/OFF the converter. Both a
Positive (no part number 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.
OUTPUT OVER VOLTAGE PROTECTION (OVP)
The Over Voltage Protection circuit comes in latching mode. The converter is latched off if the output voltage exceeds the
OVP threshold limits. The OVP latch is reset either by cycling the input voltage or toggling the Enable signal for 100ms.
OVER CURRENT PROTECTION (OCP)
The Over Current Protection circuit comes in latching mode. The converter is latched off if the load current on the output
reaches the OCP threshold limit. The OCP latch can be reset either by cycling the input voltage or toggling the Enable signal
for 100ms. Consult factory for Auto-restart option.
OVER TEMPERATURE PROTECTION (OTP)
The Over Temperature Protection circuit will shutdown the converter once the average PCB temperature 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.
MODEL: AEH/ALH80 SERIES
OCTOBER 9, 2003 - REVISION B
SHEET 8 OF 17
ASTEC [ Astec America, Inc ]
