Crane Aerospace & Electronics Power Solutions
smHF single and dual dc-dc converters
16-45 Volt input – 15 Watt
Features
small footprint 1.65 in
2
(10.6 cm
2
)
•
Qualified to MIL-PRF-38534 Class H and K
•
Input voltage range 16 to 45 VDC
•
Fully isolated
•
Operating temperature -55° to +125°C
• Radiation hardness assurance (RHA) to level R 100 krad(Si)
•
Transient protection 50 V for 50 ms
•
Fixed high frequency switching
•
Inhibit function
•
Synchronization input
•
Undervoltage lockout
models
Vdc output
SINGLE
2.5
3.3
5
12
15
DUAL
±5
±12
±15
•
Indefinite short circuit protection
description
The Interpoint™ SMHF Series™ of 28 V 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 short term
transients up to 50 volts. The package is a hermetically sealed,
projection-welded metal case. Flanged and non-flanged models
are available.
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. 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.
On dual output models, cross regulation is maintained by
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.
The small size, high power density SMHF Series low profile
package provides up to 30 watts per cubic inch.
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 1.3% with a 150 µs
recovery time, typical. Input ripple current is typically 45 mA p-p
with output ripple voltage typically 15 mV p-p.
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 (≤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 7.5 to 12 VDC. In the inhibit mode, a maximum of 5 mA
must be sunk from the inhibit pin at 28 VDC input.
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. The initial transition on the sync pin should be
a negative transition (i.e. from high state to low state).
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 VDC input voltage to keep system current
levels smooth, especially during initialization or re-start
operations.
Crane Aerospace & Electronics
Page 1 of 16
Power Solutions - Interpoint Products
SMHF Rev AC - 2013.01.31
10301 Willows Road NE, Redmond, WA 98052
The information in this document has been cleared by the Department of Defense (DoD)
+1.425.882.3100 • power@crane-eg.com
Office of Security Review (OSR) for public release. OSR case number 12-S-2814 dated
www.craneae.com/interpoint
August 28, 2012.
Crane Aerospace & Electronics Power Solutions
smHF single and dual dc-dc converters
16-45 Volt input – 15 Watt
model numbering key
Base Model
Input Voltage
SMHF
28 05 S F / K
R
S
tandard
M
icrocircuit
d
rawing
(SMd)
5962R0251002KXC
5962R9213902KXC
5962R9166402KXC
5962R9160102KXC
5962R9555902KXC
5962R9214402KXC
5962R9161402KXC
smd numbers
SMHF S
iMilar
P
art
SMHF283R3S/KR
SMHF2805S/KR
SMHF2812S/KR
SMHF2815S/KR
SMHF2805D/KR
SMHF2812D/KR
SMHF2815D/KR
Number of Outputs
(S = single, D = dual)
Case Option
(Non-flanged case has no designator
in this position)
Environmental Screening
Radiation Hardness
Assurance (RHA)
Output Voltage
F
igure
4: M
ODel
n
uMBering
k
ey
To indicate the flanged case option change the “X” to
“Z” In the SMD number. The SMD number shown is for
Class K screening, non-flanged, and Radiation Hardness
Assurance (RHA) level R. See the SMD for the numbers
for other screening and radiation levels. For exact speci-
fications for an SMD product, refer to the SMD drawing.
SMDs can be downloaded from:
http://www.landandmaritime.dla.mil/Programs/Smcr/
t
aBle
3: SMD n
uMBer
c
rOSS
r
eFerence
t
o deterMine tHe Model nuMber enter one oPtion FroM eacH category in tHe ForM below
.
category
options
Fill in For
model #
base model and
input Voltage
output Voltage
2
2R5, 3R3, 05, 12, 15
SMHF28
05, 12, 15
number of
outputs
3
S
D
case option
4
(non-flanged, leave blank)
F (flanged)
screening
5
O
H
K
SMHF28
__________
rHa
6
O
P
R
model number options
1
Notes:
1. See Model Numbering Key above for an example of a model number.
2. Output Voltage: An R indicates a decimal point. 2R5 is 2.5 volts out. The value of 2R5 and 3R3 are only available in single output models.
3. Number of Outputs: S is a single output and D is a dual output
4. Case Options: For the standard case (case E1 on page 12) leave the case option blank. For the flanged case option (case G1 on page 13), insert the letter F in the
Case Option position.
5. Screening: A screening level of O is a Space Prototype and is only available with RHA O. See “Table 9: Element Evaluation–DC-DC Converters Prototype, Class H
and Class K” on page 15 and “Table 10: Environmental Screening and RHA–DC-DC Converters Prototype, Class H and Class K, RHA P or R” on page 16 for
more information.
6. RHA: Interpoint model numbers use an “O” in the RHA designator position to indicate the “-” (dash) Radiation Hardness Assurance level of MIL-PRF-38534, which is
defined as “no RHA.” RHA O is only available with Screening level O. See “Table 10: Environmental Screening and RHA–DC-DC Converters Prototype, Class H and
Class K, RHA P or R” on page 16 for more information.
/
_______
t
aBle
4: M
ODel
n
uMBer
O
ptiOnS
www.craneae.com/interpoint
Page 4 of 16
SMHF Rev AC - 2013.01.31
Crane Aerospace & Electronics Power Solutions
smHF single and dual dc-dc converters
16-45 Volt input – 15 Watt
t
aBle
5: O
perating
c
OnDitiOnS
- a
ll
M
ODelS
- t
eSteD
/a
nalyzeD at
28 V
in
, r
aDiatiOn
l
eVel
“O”,
unleSS OtHerwiSe SpeciFieD
ALL MODELS
PARAMETER
LEAD SOLDERING TEMPERATURE
1
STORAGE TEMPERATURE
1
CASE OPERATING
TEMPERATURE
DERATING OUTPUT POWER/CURRENT
1
ESD RATING
1
1C
MIL-PRF-38534, 3.9.5.8.2
ISOLATION, ANY PIN TO CASE
EXCEPT CASE PIN
UNDERVOLTAGE LOCKOUT
1
CURRENT LIMIT
1, 2
AUDIO REJECTION
1
CONVERSION FREQUENCY
SYNCHRONIZATION
FREE RUN
-55° TO +125°C
INPUT FREQUENCY
DUTY CYCLE
1
ACTIVE LOW
ACTIVE HIGH
1
REFERENCED TO
IF NOT USED
INHIBIT ACTIVE LOW (OUTPUT DISABLED)
Do not apply a voltage to the inhibit pin
INHIBIT PIN PULLED
LOW
1
INHIBIT PIN SOURCE
CURRENT
1
REFERENCED TO
INHIBIT ACTIVE HIGH (OUTPUT ENABLED)
INHIBIT PIN CONDITION
Do not apply a voltage to the inhibit pin
OPEN INHIBIT PIN
VOLTAGE
1
7.5
% OF FULL LOAD
FULL POWER
ABSOLUTE
1
LINEARLY
MIL-STD-883
METHOD 3015
@ 500 VDC AT 25°C
CONDITIONS
10 seconds max.
MIN
—
-65
-55
-55
TYP
—
—
—
—
MAX
300
+150
+125
+135
UNITS
°C
°C
°C
From 100% at 125°C to 0% at 135°C
1000
100
—
—
—
—
480
500
40
—
4.5
—
—
60
14
140
50
550
—
—
—
—
1999
—
—
—
—
—
620
600
60
0.8
5.0
V
Megohms
pF
V
IN
%
dB
kHz
kHz
%
VDC
INPUT TO OUTPUT CAPACITANCE
1
INPUT COMMON
CONNECT TO INPUT COMMON
—
—
—
—
0.8
5
VDC
mA
INPUT COMMON
OPEN COLLECTOR OR
UNCONNECTED
—
12
V
Notes:
1. Guaranteed by qualification test and/or analysis. Not an in-line test.
2. Dual outputs: The over-current limit will trigger when the sum of the currents from both outputs reaches 140% (typical value) of the maximum
rated “total” current of both outputs.
www.craneae.com/interpoint
Page 5 of 16
SMHF Rev AC - 2013.01.31
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