MHF283R3S_14 Datasheet, PDF (1/23 Pages) Interpoint Corporation Company – MHF+ Single, Dual and Triple DC-DC Converters

Crane Aerospace & Electronics Power Solutions
MHF+ Single, Dual and Triple DC-DC Converters
28 Volt input – 15 Watt
Features
Only 0.33 inches (8.38 mm) high in a
hermetically sealed case
• Operating temperature –55° to +125°C
• Input voltage 16 to 40 Volts
-- MHF+281R9S 20 to 32 Volts
- Triple output models 16 to 48 Volts
• Transient protection
- Single and dual: 50 V for 50 ms
- MHF+281R9S: 35 V for 50 ms
- Triple: 80 V for 120 ms
• Fully isolated
• Fixed high frequency switching
• Inhibit and synchronization functions
• Indefinite short circuit protection
• Under voltage lockout
models
Output Voltage (V)
SINGLE DUAL TRIPLE
1.9
±5 +5 & ±12
3.3
±12 +5 & ±15
5
±15
5.2
5.3
12
15
28
DESCRIPTION
MHF+ Series™ SingleS and DualS
Interpoint® MHF+ Series singles and duals are high frequency
dc-dc converters offering a wide input voltage range of 16 to 40
volts (MHF+281R9S, 20 to 32 volts) and up to 15 watts of output
power. Transient protection up to 50 volts for up to 50 ms. The
converters are offered with standard screening, “ES” screening,
or fully compliant to “883” MIL-PRF-38534 Class H screening
(see Table 13 on page 23). Standard Microcircuit Drawings
(SMD) are available (see Table 3 on page 7.
Converter Design
The MHF+ Series single and dual converters are switching
regulators that use a quasi-square wave, single-ended forward
converter design with a constant switching frequency of 550 kHz
typical. Isolation between input and output circuits is provided
with a transformer in the forward path and a temperature
compensated optical link in the feedback control loop. See
Figure 1 and Figure 3 on page 4
For the MHF+ dual output models, good cross regulation is
maintained by tightly coupled output magnetics. Up to 90%
of the total output power (80% on 2805D) is available from
either output, providing the opposite output is simultaneously
carrying 10% of the total output power (20% on 2805D models).
Predictable current limit is accomplished by directly monitoring
the output load current and providing a constant current output
above the overload point.
Inhibit Function
MHF+ converters provide an inhibit terminal that can be used to
disable internal switching, resulting in no output current and very
low quiescent input current. The converter is inhibited when the
inhibit pin is pulled low (≤0.8 V = output disabled).
The unit is enabled when the pin, which is internally connected to
a pull-up resistor, is left unconnected or is connected to an open-
collector gate. The open circuit output voltage associated with the
inhibit pin is 8.5 to 12 V. In the inhibit mode, a maximum of 5 mA
must be sunk from the inhibit pin. See Figure 6 on page 5
Synchronization
An external synchronization feature is included that 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 signal input of the desired frequency to
pin 5. The capacitively coupled sync input will synchronize on a
differential signal of as low as 4 volts to as high as 5 V. For single
and dual output models, if the sync function is not used, connect
the terminal to input common.
Short Circuit Protection
MHF+ Series single and dual output 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.
Undervoltage Lockout
Undervoltage lockout prevents the single and dual output
converters from operating below approximately 14 Volts input
voltage to keep system current levels smooth, especially during
initialization or re-start operations.
Packaging
MHF+ Series of converters are packaged in hermetically sealed
metal cases and can be purchased in a flanged or non-flanged
case. The flanged option provides increased heat dissipation and
also provides greater stability when mechanically secured.
Crane Aerospace & Electronics
Power Solutions - Interpoint Products
10301 Willows Road NE, Redmond, WA, 98052
+1.425.882.3100 • [e-mail]
www.craneae.com/interpoint
Page 1 of 23
MHF+ Rev AB - 2014.10.02