Trim function or remote sense on single output models
•
Inhibit function
•
Synchronization function
SINGLE
3.3
5
12
15
VDC O
utput
mODElS
DUAL
±5
±12
±15
•
Up to 84% efficiency (up to 73% efficiency triple models)
•
Indefinite short circuit protection
TRIPLE
+5 & ±12
+5 & ±15
DESCRIPTION
The Interpoint™ SMTR Series™ of 28 volt dc-dc converters
offers up to 30 watts of output power from single, dual or
triple output configurations. They operate over the full military
temperature range of -55°C to +125°C with up to 84% efficiency
(up to 73% efficiency triple models). SMTR converters are
packaged in hermetically sealed metal enclosures, making them
ideal for use in military, aerospace and other high reliability
applications.
c
onverter
D
eSign
S
creening
SMTR converters offer screening options to Space Prototype (O),
Class H, or Class K. Radiation tolerant to Radiation Hardness
Assurance (RHA) levels of “-” (O), “P,” or “R,” per MIL-STD-
38534. 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”. See “Table 11: Element Evaluation” on page 19 and
“Table 12: Environmental Screening and RHA Levels” on page
20 for more information.
The SMTR converters are constant frequency, pulse-width
modulated switching regulators which use a quasi-square wave,
single ended, forward converter design. Tight load regulation is
maintained by using a wide bandwidth magnetic feedback and,
on single output models, through use of remote sense. On dual
output models, the positive output is independently regulated and
the negative output is cross regulated through the use of tightly-
coupled magnetics. The triple output dc-dc converter’s
design includes individual regulators on the auxiliary outputs
which provide for no cross regulation error when a minimum
300 mA load is maintained on the main (+5 V) output.
SMTR converters have an internal input filter that helps reduce
the need for external components in normal operation. Use our
SFMC EMI input filter to meet the requirements of MIL-STD-
461C’s CE03. For the lowest noise performance, connection
of the case to input common is recommended. The connection
can be hard-wired or AC coupled with a small ceramic bypass
capacitor. Indefinite short circuit protection and overload
protection are provided by a constant current-limit feature. This
protective system senses current in the converter’s secondary
stage and limits it to approximately 140% of the maximum rated
output current.
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
SMTR Rev AA - 2013.04.18
The information in this document is a derivative of documents cleared by the Department
of Defense (DoD) Office of Security Review (OSR) for public release. OSR case numbers
09-S-1002 dated March 24, 2009 and 12-S-2048 dated May 29, 2012.
Page 1 of 20
Crane Aerospace & Electronics Power Solutions
SmTR Single, Dual and Triple DC-DC Converters
28 Volt input – 30 Watt
S
ynchronization
Synchronizing the converter with the system clock allows
the designer to confine switching noise to clock transitions,
minimizing interference and reducing the need for filtering. In
sync mode, the converter will run at any frequency between 500
kHz and 675 kHz. The sync control operates with an active high
at any duty cycle between 40% and 60%. The sync pin should be
connected to input common pin when not in use.
i
mproveD
D
ynamic
r
eSponSe
The SMTR Series feed-forward compensation system provides
excellent dynamic response and noise rejection. Audio rejection
is typically 40 dB (50 dB for Triple output models). The min. to
max. step line transient response is typically less than 4%.
i
nhibit
F
unction
W
iDe
v
oltage
r
ange
SMTR converters are designed to provide full power operation
over a full 16 to 40 VDC voltage range. Operation below 16
volts, including MIL-STD-704D emergency power conditions
is possible with derated power. Refer to the low line dropout
graphs (“Figure 23” on page 13, “Figure 31” on page 14 and
“Figure 32” on page 14) for details.
SMTR converters provide an inhibit terminal that can be used to
disable internal switching, resulting in no output voltage and very
low quiescent input current. The converter is inhibited when the
inhibit pin is pulled below 0.8 V and enabled when its inhibit pin
is left floating. An external inhibit interface should be capable of
pulling the converter’s inhibit pin below 0.8 V while sinking the
maximum inhibit current and also allowing the inhibit pin to float
high to enable the converter. A voltage should not be applied to
the inhibit pin. The open circuit voltage present on the inhibit pin
is 9 to 11 V.
www.craneae.com/interpoint
SMTR Rev AA - 2013.04.18
Page 2 of 20
Crane Aerospace & Electronics Power Solutions
SmTR Single, Dual and Triple DC-DC Converters
28 Volt input – 30 Watt
TRIm AND REmOTE SENSE (AvAIlAblE ON SINglE OUTPUT mODElS ONly)
SMTR SINGLE OUTPUT CONVERTER
1
+VIN
OUTPUT
COMMON
SENSE
RETURN
SENSE
10
INPUT
COMMON
POSITIVE
OUTPUT
4
1
3
6
1
RT
RL
5
EXTERNAL TRIM CONNECTION
1 Make connections at converter.
F
igure
1: t
rim
c
onnection
1, 2, 3
SMTR SINGLE OUTPUT CONVERTER
1
+VIN
OUTPUT
COMMON
SENSE
RETURN
SENSE
10
INPUT
COMMON
POSITIVE
OUTPUT
4
2
RL
2
3
6
5
REMOTE SENSE CONNECTION
2 Make connections at load.
F
igure
2: r
emote
S
enSe 2, 3
Trim Formulas Vout = desired output voltage;
R
T
= trim resistor
3.3V:
5V:
12V:
15V:
R
T
= 1300 * Vout
1.2475
R
T
= 1300 * Vout
1.2475
R
T
= 1300 * Vout
1.2475
R
T
= 1300 * Vout
1.2475
– 4304
– 6512
– 15631
– 19498
Notes for Remote Sense and Trim
1. When trimming output voltage and/or remote sensing, the
total output voltage increase must be less than 0.6 volts at the
converters pins. Do not exceed maximum power.
2. If neither voltage trim nor remote sense will be used, connect pin 3
to pin 4 and pin 5 to pin 6 or the output voltage will increase by 1.2
volts.
3. CAUTION: The converter will be permanently damaged if the
positive remote sense (pin 6) is shorted to ground. Damage may
also result if the output common or positive output is disconnected
from the load with the remote sense leads connected to the load.
4. 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 at powerapps@
crane-eg.com
www.craneae.com/interpoint
SMTR Rev AA - 2013.04.18
Page 3 of 20
Crane Aerospace & Electronics Power Solutions
SmTR Single, Dual and Triple DC-DC Converters
28 Volt input – 30 Watt
PIN OUT
PINS NOT IN USE
Pin
1
2
3
4
5
6
7
8
9
10
Single Output
Positive Input
Inhibit
Sense Return
Output Common
Positive Output
Positive Sense
Case Ground
Case Ground
Sync
Input Common
Dual Output
Inhibit
Triple Output
Positive Input
Main (+5) Output
Output Common
Neg. Aux. Output
Pos. Aux. Output
Case Ground
Case Ground
Inhibit
Sync
Input Common
Positive Input
Positive Output
Output Common
Negative Output
Case Ground
Case Ground
Case Ground
Sync
Input Common
t
able
1: p
in
o
ut
Inhibit
Sync In
Leave unconnected
Connect to Input Common
Must be connected to
appropriate outputs
not in
Sense Lines
t
able
2: p
inS
u
Se
Dot on top of cover indicates pin one.
Dot on top of cover indicates pin one.
1
2
3
4
5
1
2
3
4
5
10
BOTTOM VIEW
SMTR SINGLE
FLANGED AND NON-FLANGED
9
8
7
BOTTOM VIEW
SMTR DUAL
FLANGED AND NON-FLANGED
10
9
8
7
6
6
Dotted line outlines flanged package option.
For dimensions see “Figure 34: Cases H2” on page 16
and “Figure 36: Cases K3” on page 18.
Dotted line outlines flanged package option.
For dimensions see “Figure 34: Cases H2” on page 16
and “Figure 36: Cases K3” on page 18.
F
igure
3: p
in
o
ut
Smtr S
ingle
o
utput
m
oDelS
F
igure
4: p
in
o
ut
Smtr D
ual
o
utput
m
oDelS
Squared corner and dot on top
of package indicate pin one.
1
2
3
4
5
BOTTOM VIEW
SMTR TRIPLE
FLANGED AND NON-FLANGED
10
9
8
7
6
Dotted line outlines flanged package option.
For dimensions see “Figure 33: Case F1” on page 15
and “Figure 35: Case J1” on page 17.
F
igure
5: p
in
o
ut
Smtr t
riple
Page 4 of 20
www.craneae.com/interpoint
SMTR Rev AA - 2013.04.18
Crane Aerospace & Electronics Power Solutions
SmTR Single, Dual and Triple DC-DC Converters
28 Volt input – 30 Watt
mODEl NUmbERINg kEy
Base Model
Input Voltage
SMTR
28 512 T
F / K R
S
tanDarD
M
iCrOCirCuit
D
rawing
(SMD)
5962R0150102KXC
5962R9306802KXC
5962R9306902KXC
5962R9307002KXC
5962R9320502KXC
5962R9307102KXC
5962R9307202KXC
5962R9307402KXC
SmD NUmbERS
SMtr S
iMilar
p
art
SMTR283R3S/KR
SMTR2805S/KR
SMTR2812S/KR
SMTR2815S/KR
SMTR2805D/KR
SMTR2812D/KR
SMTR2815D/KR
SMTR28515T/KR
Output Voltage
(Main and aux. Vout for triple models)
Number of Outputs
(S=single, D=dual, T=triple)
Case Option
("F" indicates flanged option, non-flanged
case has no designator in this position)
Screening
Radiation Hardness
Assurance (RHA)
F
igure
6: 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 specifications for an SMD product, refer to the
SMD drawing. SMDs can be downloaded from:
http://www.dscc.dla.mil/programs/smcr
t
able
3: SmD n
umberS
t
O
CATEgORy
OPTIONS
FIll IN FOR
mODEl #
base model and
Input voltage
DeterMine the MODel nuMber enter One OptiOn frOM
Output voltage
1
3R3, 05, 12, 15
eaCh CategOry in the fOrM belOw
.
Number of
Outputs
2
S
D
T
_______
/
Case Options
3
Screening
4
O
H
K
RHA
5
O
P
R
_______
mODEl NUmbER OPTIONS
(non-flanged, leave blank)
F (flanged)
SMTR
05, 12, 15
512, 515
__________
SMTR
__________
Notes:
1. Output Voltage: An R indicates a decimal point. 3R3 is 3.3 volts out. The 3R3 is only available in single output models. The 512 and 515 triple output converters
are +5 volt main and ±12 or ±15 volt auxiliaries.
2. Number of Outputs: S is a single output, D is a dual output, and T is a triple output
3. Case Options: For the standard case (cases “Figure 33: Case F1” on page 15 and “Figure 34: Cases H2” on page 16) leave the case option blank. For the
flanged case option (cases “Figure 35: Case J1” on page 17 and “Figure 36: Cases K3” on page 18), insert the letter F in the Case Option position.
4. Screening: A screening level of O is a Space Prototype and is only available with RHA O. See “Table 11: Element Evaluation” on page 19 and “Table 12:
Environmental Screening and RHA Levels” on page 20 for more information.
5. 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 12: Environmental Screening and RHA Levels” on page 20 for more
