SMHF282R5S Datasheet, PDF (2/15 Pages) Interpoint Corporation Company – Fully qualified to Class H or K -55°C to +125°C operation 16 to 40 VDC input

Crane Aerospace & Electronics Power Solutions
SMHF Single and Dual DC/DC Converters
28 Volt input – 15 Watt
Synchronization
A synchronization feature is included with the SMHF Series that
allows the user to match the switching frequency of the converter
to the frequency of the system clock. This allows the user
to adjust the nominally 550 kHz operating frequency to any
frequency within the range of 500 kHz to 600 kHz. This is initiated
by applying a compatible input of the desired frequency to pin 5.
The initial transition on the sync pin should be a negative transi-
tion (i.e. from high state to low state)
Undervoltage Lockout
Undervoltage lockout prevents the units from operating below
approximately 14 VDC input voltage to keep system current
levels smooth, especially during initialization or re-start opera-
tions.
Short Circuit Protection
SMHF Series converters provide short circuit protection by
restricting the output current to approximately 115% of the
full load output current. The output current is sensed in the
secondary stage to provide highly predictable and accurate
current limiting, and to eliminate foldback characteristics.
Positive
Input
5 µH
Inhibit
Input
Common
2 µF
PWM
Controller
I_C
FET
Driver
Limit
I_D
Ref.
Figure 1: SMHF Single Output - Block Diagram
Positive
Output
Output
Common
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Rev D - 20070404