SMHF283R3S_15 Datasheet, PDF (1/15 Pages) Interpoint Corporation Company – SMHF Single and Dual DC-DC Converters

Crane Aerospace & Electronics Power Solutions
SMHF Single and Dual DC-DC Converters
16-45 Volt Input – 15 Watt
Features
• Radiation tolerant space dc-dc converter
-- Single event effects (SEE) LET performance to
86 MeV cm²/mg
-- Total ionizing dose (TID) guaranteed per MIL-STD-883
method 1019, radiation hardness assurance (RHA)
P = 30 krad(Si), L = 50 krad(Si), R = 100 krad(Si)
-- 50 - 300 rad(Si)/sec dose rate (Condition A)
-- 10 mrad(Si)/sec dose rate (Condition D)
• Operating temperature -55°C to +125°C
• Qualified to MIL-PRF-38534 Class H and K
• Input voltage range 16 to 45 volts
• Transient protection 50 volts for 50 ms
• Fully isolated
• Fixed high frequency switching
• Inhibit function
• Synchronization input
• Indefinite short circuit protection
• Undervoltage lockout
description
The Interpoint^® SMHF Series™ of 28 volt dc-dc converters offers
a wide input voltage range of 16 to 45 volts and up to 15 watts of
output power. The units are capable of withstanding transients up
to 50 volts for up to 50 ms.
Screening
SMHF converters offer screening to Class H or K and radiation
hardness assurance (RHA) levels P - 30 krad(Si), L - 50 krad(Si)
or R - 100 krad(Si). Single event effects (SEE) LET performance
to 86 MeV cm²/mg. See Table 10 on page 15 for more
information.
Converter Design
The SMHF 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 opto-coupler
in the feedback control loop. The opto-coupler is radiation
tolerant and is especially selected for space applications.
Models
Output Voltage (V)
SINGLE
DUAL
3.3
±5
5
±12
5.2
±15
12
15
The SMHF converter’s feed-forward compensation system
provides excellent dynamic response and noise rejection. Audio
rejection is typically 50 dB. Typical output voltage response for
a 50% to 100% step load transient is as low as 1.8% with a 150
µs recovery time, typical. See Table 5 on page 5 for more
information.
SMHF converters provide an inhibit terminal that can be used
to disable internal switching, resulting in no output and very
low quiescent input current. The converter is inhibited when the
inhibit pin is pulled low. 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. See Table 5 on page
5 for more information.
The SMHF Series’ synchronization feature 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 nominal
550 kHz operating frequency to any frequency within the range of
500 kHz to 600 kHz by applying a compatible input of the desired
frequency to pin 5.
Dual output models maintain cross regulation with tightly
coupled output magnetics. Up to 70% of the total output power
is available from either output, providing the opposite output
is simultaneously carrying 30% of the total output power.
Predictable current limit is accomplished by directly monitoring
the output load current and providing a constant current output
above the overload point.
SMHF Series converters provide short circuit protection by
restricting the output current to approximately 140% 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 prevents the units from operating below
approximately 14 volts input to keep system current levels
smooth, especially during initialization or re-start operations.
Crane Aerospace & Electronics
Power Solutions - Interpoint Products
10301 Willows Road NE, Redmond, WA 98052
[phone] • [e-mail]
www.craneae.com/interpoint
Page 1 of 15
SMHF Rev AF - 2015.10.28