Crane Aerospace & Electronics Power Solutions
sMFL single and dual dc-dc converters
28 VoLt input – 65 Watt
Features
•
Radiation tolerant space DC-DC converter
- Single event effects (SEE) LET performance to
86 MeV cm
2
/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)
•
Parallel up to 3 converters—maximum recommended power
is 80% of the total available power.
•
Operating temperature -55°C to +125°C
•
Input voltage range 16 to 40 volts
•
Qualified to MIL-PRF-38534 Class H and K
•
Transient protection up to 80 volts for 50 ms
MODELS
OuTPuT VOLTAgE (V)
•
Fully isolated, magnetic feedback
•
Fixed high switching frequency
- Converter will shut down at an input voltage above
approximately 45 volts
SINgLE
3.3
5
12
15
DuAL
±5
±12
±15
•
Remote sense and output trim on single output models
•
Primary and secondary inhibit function
•
Synchronization input and output
•
Indefinite short circuit protection
•
High power density with up to 85% typical efficiency
description
The Interpoint
®
SMFL Series™ 28 volt DC-DC converters are
rated up to 65 watts output power over a -55°C to +125°C
temperature range with a 28 volt nominal input. On dual output
models, up to 70% of the rated output power can be drawn from
either the positive or negative outputs. The welded, hermetically
sealed package is only 3.005 x 1.505 x 0.400 inches.
Isolation between input and output circuits is provided with a
transformer in the forward path and wide bandwidth magnetic
coupling in the feedback control loop. The SMFL Series uses a
unique dual loop feedback technique that controls output current
with an inner feedback loop and output voltage with a cascaded
voltage mode feedback loop.
The additional secondary current mode feedback loop improves
transient response in a manner similar to primary current mode
control and allows for ease of paralleling.
Tight load regulation is achieved through a wide-bandwidth
magnetic feedback circuit.
The SMFL Series converters have two inhibit terminals (Inhibit
1 and Inhibit 2) that can be used to disable power conversion,
resulting in a very low quiescent input current. See Table 5 on
page 6 for specifications.
Converters may be synced to an external clock (525 to 675 kHz)
or to one another by using the sync in or out pins. See Table 5
on page 6 for specifications.
S
creening
SMFL converters offer screening options to space prototype (O),
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 cm
2
/mg. See Table 9
on page 13 and Table 10 on page 14 for more information.
D
eSign
F
eatureS
The SMFL Series converters are switching regulators that use a
quasi-square wave, single ended forward converter design with a
constant switching frequency of 600 kHz.
i
nhibit
S
ync
Crane Aerospace & Electronics
Power Solutions – Interpoint Products
10301 Willows Rd. NE, Redmond, WA 98052
+1 425.882.3100 • power@crane-eg.com
www.craneae.com/interpoint
SMFL Rev AD - 2017.05.24
Page 1 of 14
Crane Aerospace & Electronics Power Solutions
sMFL single and dual dc-dc converters
28 VoLt input – 65 Watt
S
enSe anD
t
rim
Single output models provide sense to maintain voltage at the
load. The converters output voltage can also be trimmed up. See
Figure 1.
The units designated as slaves have the Master/Inhibit 2 pin (pin
12) connected to the Sense Return pin (pin 9) of the master unit.
Figure 2 on page 3 shows the typical setup for two or three
units in parallel.
A second slave unit may be placed in parallel with a master and
slave; this requires the Triple pin (pin 3) of the master unit to be
connected to the Sense Return pins (pin 9) shown in Figure 2 on
page 3.
In current sharing mode, the converters function as a current
source. For this reason it is important that their outputs be
connected to the common ground at all times to prevent an
excessively high voltage at their outputs.
c
urrent
S
haring anD
P
arallel
O
PeratiOn
For increased power parallel up to 3 converters. The maximum
recommended power is 80% of the total available power. Multiple
SMFL converters may be used in parallel to drive a common
load. Only single output models with Sense and Sense Return
can be used in the share mode. In this mode of operation the
load current is shared by two or three SMFL converters.
In current sharing mode, one SMFL converter is designated as a
master. The Slave pin (pin 11) of the master is left unconnected
and the Master/Inhibit 2 pin (pin 12) of the master is connected to
the Slave pin (pin 11) of the slave units.
28V
Inhibit
Sync In
+
–
1
2
3
4
5
6
Positive Input
Input Common
Triple (TRI)
Inhibit 1
Sync Out
Sync In
Positive Sense 10
9
Sense Return
8
Output Common
7
Positive Output
Master/Inhibit 2 12
Slave 11
REMOTE SENSE CONNECTION
+
–
1
2
3
4
5
6
Positive Input
Input Common
Triple (TRI)
Inhibit 1
Sync Out
Sync In
Master/Inhibit 2 12
11
Slave
10
Positive Sense
9
Sense Return
8
Output Common
7
Positive Output
–
+
RL
28V
Inhibit
Sync In
RA
OUTPUT VOLTAGE ADJUST CONNECTION
–
+
RL
V
OuT
INCREASE
VOLTS
0.1
0.2
0.3
0.4
0.5
3.3 V
66
131
196
262
349
5V
77
R
A
(Ω)
12 V
27
55
82
109
139
15 V
21
43
64
86
109
153
230
307
396
Notes
1. When using remote sense for voltage
compensation or when using remote sense
for trim, the output will drift over temperature.
Contact Applications Engineering for more
information powerapps@crane-eg.com.
2. Do not exceed the maximum rated power.
F
igure
1: S
enSe
c
OnnectiOnS anD
t
rim
t
able
– S
ingle
O
utPut
m
ODelS
www.craneae.com/interpoint
SMFL Rev AD - 2017.05.24
Page 2 of 14
Crane Aerospace & Electronics Power Solutions
sMFL single and dual dc-dc converters
28 VoLt input – 65 Watt
1
2
3
4
5
6
28V
Inhibit
Sync In
+
–
Positive Input
Input Common
Triple (TRI)
Inhibit 1
Sync Out
Sync In
Master/Inhibit 2
12
Slave
11
Positive Sense
Sense Return
Positive Output
10
9
8
7
MASTER
Output Common
CONNECT Triple (TRI) ONLY WHEN 2 SLAVES ARE USED
1
2
3
4
5
6
–
+
RL
Positive Input
Input Common
Triple (TRI)
Inhibit 1
Sync Out
Sync In
Master/Inhibit 2
12
Slave
11
Positive Sense
10
Sense Return
9
SLAVE 1
Output Common
8
7
Positive Output
1
2
3
4
5
6
Positive Input
Input Common
Triple (TRI)
Inhibit 1
Sync Out
Sync In
Master/Inhibit 2
12
Slave
11
Positive Sense
10
Sense Return
9
SLAVE 2
Output Common
8
7
Positive Output
Notes
1. No one converter may carry more than its maximum rated current.
2. Individual converter operation, load and layout may affect the actual current shared. Contact Applications Engineering for more
information powerapps@crane-eg.com.
3. When paralleling SMFLs a diode is required at the input of each inhibit pin as SMFLs do not have an internal diode on the inhibit pin.
F
igure
2: P
arallel
c
OnnectiOnS
– S
ingle
O
utPut
m
ODelS
www.craneae.com/interpoint
SMFL Rev AD - 2017.05.24
Page 3 of 14
Crane Aerospace & Electronics Power Solutions
sMFL single and dual dc-dc converters
28 VoLt input – 65 Watt
pin out
pin
1
2
3
4
5
6
7
8
9
10
11
12
single output
Positive Input
Input Common
Triple (TRI)
Inhibit 1 (INH1)
Sync Out
Sync In
Positive Output
Output Common
Sense Return
Positive Sense
Slave
Master/Inhibit 2
(MSTR/INH2)
dual output
Positive Input
Input Common
Triple (TRI)
Inhibit 1 (INH1)
Sync Out
Sync In
Positive Output
Output Common
Negative Output
No connection
Slave
Master/Inhibit 2
(MSTR/INH2)
Triple (TRI)
Inhibit 1 (INH1)
Sync Out
Sync In
Sense Return
Positive Sense
Slave
Master/Inhibit 2
(MSTR/INH2)
pins not in use
Leave unconnected
Leave unconnected
Leave unconnected
Connect to Input Common
Connect to appropriate outputs
Connect to appropriate outputs
Leave unconnected
Leave unconnected
t
able
2: P
inS
n
Ot in
u
Se
t
able
1: P
in
O
ut
Angled corner indicates pin one.
1
2
3
4
5
6
12
11
TOP VIEW SMFL
(Pin side, marked side)
10
9
8
7
See Figure 18 on page 12 for dimensions.
F
igure
3: P
in
O
ut
www.craneae.com/interpoint
SMFL Rev AD - 2017.05.24
Page 4 of 14
Crane Aerospace & Electronics Power Solutions
sMFL single and dual dc-dc converters
28 VoLt input – 65 Watt
ModeL nuMbering key
Base Model
Input Voltage
SMFL
28 15 D / K
R
S
tandard
M
icrocircuit
d
rawing
(SMd)
5962R0621301KXC
5962R9316301KXC
5962R9316201KXC
5962R9316101KXC
5962R9319101KXC
5962R9319201KXC
5962R9319301KXC
sMd nuMbers
SMFL S
erieS
S
iMiLar
P
art
SMFL283R3S/KR
SMFL2805S/KR
SMFL2812S/KR
SMFL2815S/KR
SMFL2805D/KR
SMFL2812D/KR
SMFL2815D/KR
Output Voltage
Number of Outputs
(S = single, D = dual)
Environmental
Screening
Radiation Hardness
Assurance (RHA)
F
igure
4: m
ODel
n
umbering
K
ey
The SMD number shown is for Class K screening,
non-flanged,radiation hardness assurance (RHA) level
R. For exact specifications for an SMD product, refer to
the SMD drawing. SMDs can be downloaded from
https://landandmaritimeapps.dla.mil/programs/smcr/
t
able
3: SmD n
umber
c
rOSS
r
eFerence
t
o
category
base Model and
input Voltage
deterMine the ModeL nuMber enter one oPtion FroM
each category in the ForM beLow
.
output Voltage
1
3R3, 05, 12, 15
number of
outputs
2
S
D
ModeL nuMber options
screening
3
O
H
K
rHa
4
O
P
L
R
options
FiLL in For
ModeL #
SMFL28
05, 12, 15
SMFL28
/
_______
Notes
1. Output Voltage: An R indicates a decimal point. 3R3 is 3.3 volts out. The value of 3R3 is only available in single
output models.
2. Number of Outputs: S is a single output and D is a dual output.
3. Screening: A screening level of O is a space prototype and is only used with RHA O. See Table 9 on page 13 and
Table 10 on page 14 for more information.
4. RHA: Interpoint model numbers use an “O” in the RHA designator position to indicate the “-” (dash) RHA level of
MIL-PRF-38534, which is defined as “no RHA.” RHA O is only available with screening level O. See Table 10 on
page 14 for more information.
t
able
4: m
ODel
n
umber
O
PtiOnS
www.craneae.com/interpoint
SMFL Rev AD - 2017.05.24
Page 5 of 14
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