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TYPICAL APPLICATION WITH OPTIONS
DESCRIPTION
The DHD2805S DC-DC converter provides the rugged-
ness, reliability, and features required to meet the advanced
design challenges of today鈥檚 hi-rel market. This is accom-
plished while retaining a power density of 17 W/in
3
and 425
mW/gram of power/package performance. The use of ad-
vanced substrate and reflow soldering techniques during
construction results in a rugged, cost-effective, and com-
pletely solderable package.
DHD2805S hybrid converter series utilizes all ceramic
capacitors and surface mount magnetics to provide reliable
operation at all operating temperatures while surviving very
high G forces.
DHD2805S standard features include output fault monitor-
ing and/or turn on voltage point programming via the shut-
down pin. All three functions may be implemented simulta-
neously with a minimum of external components. An output
voltage adjustment/load compensation pin is also standard.
Fault tolerant design protects these converters from most
external circuit faults. The output and output adjust pins will
withstand +35 V while the shutdown pin will withstand +50 V
protecting the converters from a variety of system or board
faults i.e. solder bridges etc. Unique load fault protection
circuitry allows this converter to pull up loads having difficult
static load line characteristics and allows short term load
excursions significantly beyond ratings in most applications.
A transformer isolated forward converter topology operat-
ing at a switching frequency of 400 KHz allows operation over
a wide input voltage range. Internal filtering of both input and
output eliminates the need for external capacitors in many
applications.
The 8-pin DIP package is hermetically sealed and isolated
from the internal circuits. Heat sinking is recommended for full
power operation at elevated ambient temperatures.
BLOCK DIAGRAM
6
1
2
5
PWM
FEED FORWARD
CONTROLLER
7
ERROR AMPLIFIER
REFERENCE AND
ISOLATION
3
EXTERNAL CONNECTIONS
1
2
3
4
5
1
+OUTPUT
-OUTPUT
ADJUST/COMP
NO CONNECTION
SHUTDOWN PLUS
8
7
6
CASE
-INPUT
+INPUT
Rev. - 3/01
1
2
3
4
5
