• Trim function or remote sense on single output models
• Synchronization function
• Indefinite short circuit protection
• Up to 84% efficiency (up to 73% efficiency triple models)
VDC O
utput
SIngLE
DUAL
TRIPLE
1.5
±5
+5 & ±12
2.5
±12
+5 & ±15
3.3
±15
5
12
15
MODELS
DESCRIPTION
The Intepoint™ 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.
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 Screening Tables 1 and 2 for more information.
SMTR converters have an internal input filter that help 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 125% of the maximum rated
output current.
S
ynchronization
c
onverter
D
eSign
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 SMTR Triple Series 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.
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.
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.
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%.
Crane Aerospace & Electronics
Crane Electronics, Inc.
Power Solutions – Interpoint™
PO Box 97005 • Redmond, WA 98073-9705
425.882.3100 • power@crane-eg.com
www.craneae.com/interpoint
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 09-S-1960 dated June 22, 2009.
SMTR Rev g - 2011.05.04
Page 1 of 20
Crane Aerospace & Electronics Power Solutions
SMTR Single, Dual and Triple DC/DC Converters
28 VOlT INPuT – 30 WaTT
i
nhibit
F
unction
SMTR 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 to ≤0.8V. 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 9 to 11
VDC. In the inhibit mode, a maximum of 8 mA must be sunk from
the inhibit pin.
OPERaTINg CONDITIONS aND ChaRaCTERISTICS
Input Voltage Range
• 16 to 40 VDC continuous
• 50 V for 50 msec transient
audio Rejection
• 40 dB typ (50 dB typ, triple output)
Output Power
• Up to 30 watts depending on model
Conversion Frequency
• Free run 550 min, 600 typ, 650 max kHz
• External sync 500 to 675 kHz
lead Soldering Temperature (10 sec per pin)
• 300°C
Storage Temperature Range (Case)
• -65°C to +150°C
Case Operating Temperature (Tc)
• -55°C to +125°C full power
• -55°C to +135°C absolute
Sync and inhibit (inh1, inh2)
Sync
• Sync In
‣
Input frequency 500 to 675 Hz.
‣
Duty cycle 40% min, 60% max
‣
Active low 0.8 V max
‣
Active high 4.5 V min, 5 V max
‣
Referenced to input common
• Sync Out
‣
Referenced to input common
Derating Output Power/Current
• Linearly from 100% at 125°C to 0% at 135°C
Output Voltage Temperature Coefficient
• 100 ppm/°C typical single and dual outputs
• 200 ppm/°C main, 300 ppm/°C aux triple output
Input to Output Capacitance
• 50 pF typ (100 pF typ triple outputs)
Current limit
• 125% of full load typical
Isolation
• 100 megohm minimum at 500 VDC
• Any pin to case, except case pin
Inhibit (do not apply a voltage to the inhibit pin)
• Converter Disabled (active low)
‣
Pull voltage to 0.8 V or below by connecting to ground or
other method.
‣
Inhibit pin source current, 8 mA max
‣
Referenced to input common
• Converter Enabled (active high)
‣
Inhibit pin open or through an open collector
‣
If not used, leave unconnected
‣
Open pin voltage 9 to 11 V
MEChaNICal aND ENVIRONMENTal
Size (maximum)
• Single and dual output
‣
non-flanged: 2.100 x 1.115 x 0.400 inches
(53.34 x 28.32 x 10.16 mm) See case H2 for dimensions.
‣
Flanged: 2.910 x 1.115 x 0.400 inches
(73.91 x 28.32 x 10.16 mm) See case K3 for dimensions.
• Triple output
‣
non-flanged: 1.950 x 1.350 x 0.405 inches
(49.53 x 34.29 x 10.29 mm) See case F1 for dimensions.
‣
Flanged: 2.720 x 1.350 x 0.405 inches
(69.09 x 34.29 x 10.29 mm) See case J1 for dimensions.
Screening
Space Prototype (O), Class H, or Class K are 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 Screening Tables 1 and 2 for more information. Available
configurations are: OO, HP, KP, HR, and KR
Weight (maximum)
• Single and dual non-flanged 50 grams, flanged 52 grams
• Triple non-flanged 58 grams, flanged 62 grams
www.craneae.com/interpoint
Page 2 of 20
SMTR Rev g - 2011.05.04
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: R
T
= 1300 * Vout
1.2475
5V: R
T
= 1300 * Vout
1.2475
12V: R
T
= 1300 * Vout
1.2475
15V: R
T
= 1300 * Vout
1.2475
www.craneae.com/interpoint
– 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 posi-
tive 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
Page 3 of 20
SMTR Rev g - 2011.05.04
Crane Aerospace & Electronics Power Solutions
SMTR Single, Dual and Triple DC/DC Converters
28 VOlT INPuT – 30 WaTT
PIN OuT
Pin
1
2
3
4
5
6
7
Single Output
Positive Input
Inhibit
Dual Output
Inhibit
Positive Input
Positive Output
Triple Output
Positive Input
Sense Return
Main (+5) Output
Output Common
neg. Aux. Output
Pos. Aux. Output
Case ground
Inhibit
Sync
Case ground
Output Common
Positive Output
Positive Sense
Case ground
Sync
Case ground
Input Common
Output Common
negative Output
Case ground
Case ground
Case ground
Sync
Input Common
8
9
10
Input Common
Dot on top of cover indicates pin one.
Dot on top of cover indicates pin one.
1
2
3
4
5
10
BOTTOM VIEW
SMTR SINGLE
FLANGED AND NON-FLANGED
9
8
7
1
2
3
4
5
6
BOTTOM VIEW
SMTR DUAL
FLANGED AND NON-FLANGED
10
9
8
7
6
Dotted line outlines flanged package option.
Dotted line outlines flanged package option.
F
igure
3: p
in
O
ut
Smtr S
ingle
O
utput
m
ODelS
See cases H2 and K3 for dimensions.
F
igure
4: p
in
O
ut
Smtr D
ual
O
utput
m
ODelS
See cases H2 and K3 for dimensions.
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.
See cases F1 and J1 for dimensions.
F
igure
5: p
in
O
ut
Smtr t
riple
Inhibit
Sync In
Leave unconnected
PINS NOT IN uSE
Sense lines
www.craneae.com/interpoint
Connect to Input Common
Must be connected to appropriate outputs
Page 4 of 20
SMTR Rev g - 2011.05.04
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)
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
o
n
the lineS beloW
,
enter one Selection From each category to Determine the moDel number
.
MODEl SElECTION
CaTEgORy
SMTR28
Base Model and
Input Voltage
SMTR28 is the only
available selection
Output Voltage
1
1R5, 2R5, 3R3, 05, 12, 15
05, 12, 15
512, 515
number of
Outputs
2
S
D
T
Case Option
3
(NON-FlaNgED
leave blank)
F (FlaNgED)
/
Screening
4
O
h
k
_______
RHA
5
O
P
R
SElECTION
notes:
1. Output Voltage: An R indicates a decimal point. 1R5 is 1.5 volts out. The value of 1R5, 2R5, and 3R3 are 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 F1 and H2 on pages 15 and 16) leave the case option blank. For the flanged case option (cases J1 and K3 on
pages 17 and 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 Screening Tables 1 and 2 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 Screening Table 2 for more information.
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