Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters
28 VOLT INPUT – 35 WATT
FEATURES
•
•
•
•
•
•
•
-55°C to +125°C operation
19 to 56 VDC input
80 V for 100 ms transient protection
Dual Magnetic feedback
Inhibit function and output trim
Indefinite short circuit protection
Radiation tolerant to
1 x 10
12
protons/cm
2
neutron or proton fluence
10
11
rads(Si)/sec dose rate
3 x 10
5
rads(Si) total dose
SEU 60 MeV cm
2
/mg
•
•
•
•
•
Meets MIL-STD-704A emergency operation and tran-
sient standards
No minimum load required
5 port isolated design
Isolated synchronization input
Output trimmable up to +25% and -45% (see trim
instructions)
MODELS
VDC O
UTPUT
SINGLE
3.3
5
12
15
DUAL
±5
±12
±15
• Topology – Two-Phase Flyback
TRIPLE
+3.3 & ±12
+3.3 & ±15
+5 & ±12
+5 & ±15
DESCRIPTION
The SMRT Series™ of DC/DC converters offers up to 35
watts of power in a radiation tolerant design. The low profile
SMRT converters are manufactured in Interpoint’s fully certified
and qualified MIL-STD-1772 production facility and packaged
in hermetically sealed steel cases. They are ideal for use in
programs requiring high reliability, small size, and high levels of
radiation hardening assurance.
The SMRT converters are switching regulators which use a two-
phase, phase shifted flyback design with a nominal switching
frequency of 300 kHz. Close regulation is maintained with
advanced constant frequency pulse width modulation design
techniques. The SMRT’s feed-forward compensation and
discontinuous topologies provide high levels (80 dB peak) of
input-to-output ripple rejection. A minimum load of 2% of full load
should be used on outputs at TID of 100k rads(Si) or greater to
ensure tight regulation over the full input range.
Two independent feedback loops are used to regulate the dual
and triple outputs, one feedback loop regulates the two-phased
single output. Each set of outputs is electrically isolated from
the other and from the input. Sets are defined as follows:
Two paralleled power trains supplying a single output; one
independent power train providing a single output; and one
independent power train providing two outputs (neg. output is
cross-regulated). This product configuration eliminates cross
regulation effects between output sets.
Configurations include:
• Single Output: One two-phased single output
• Dual Output: Two single phase single outputs
• Triple Output: One single phase independent Main output and one
single phase dual output. (± Auxiliary output).
U
NDERVOLTAGE
L
OCKOUT
The converters have an undervoltage lockout that will allow
power conversion at 17 volts on a rising input voltage and a
conversion shut-down on a falling voltage at approximately 14.5
volts.
Crane Aerospace & Electronics
Electronics Group (Interpoint Brand)
PO Box 97005 • Redmond WA 98073-9705
425.882.3100 • electronics@craneae.com
www.craneae.com
Page 1 of 17
Rev B – 20080213
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters
28 VOLT INPUT – 35 WATT
I
NHIBIT
F
UNCTION
The SMRT Series incorporates an inhibit terminal that can be
used to disable internal switching. The converter is inhibited
when a low (≤ 0.4 V) signal is applied to the inhibit pin. In the
inhibit mode the inhibit pin current requirement is less than ~2
mA. The converter resumes normal operation when a high (≥ 2.4
V) signal or open circuit is applied to the inhibit pin. The open
circuit voltage of the inhibit is 5 to 6 volts.The maximum allowable
voltage applied to the inhibit pin is 10 VDC.
S
CREENING
SMRT converters offer the following screening options: Space
Prototype (O), Class H, or Class K. Radiation tolerant to
Radiation Hardness Assurance (RHA) levels of “-” (O), “P”, “R” or
“F”, per MIL-PRF-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 “Class H and K, MIL-PRF-38534 Screening”
tables for more information.
EMI
S
YNCHRONIZATION
An isolated sync input allows this input to be connected to any of
the devices three returns. It can be referenced to the input return
or any of the output returns. Input current into this pin is limited
by a series 1k ohm resistance.
The SMRT has a built-in EMI input filter which brings the
conducted emissions into compliance with both methods of
MIL-STD-461, revisions C-CE03 and D-/E-CE102.
S
ENSE
Tight load regulation is maintained via wide bandwidth magnetic
feedback and through the use of remote sense on single output
models and one output (Output “A”) of the dual units. The sense
feature can be used to adjust the output voltage by connecting a
resistor between the sense line and the positive output.
O
UTPUT
V
OLTAGE
T
RIM
The output voltage of each set can be trimmed up by up to 25%,
or down by up to 45% of nominal (varies by model, see trim
instructions). The following are “sets” of voltages in relation to
trim:
• Triple output models: Main output is one set, the dual outputs are
another set.
• Dual outputs: Each output is a “set.”
One set can be trimmed using the trim pin, the other set can be
trimmed (up only) using the sense pin.
• Single: One set
S
ENSE
A
DJUST
I
NSTRUCTIONS
(U
P
O
NLY
)
- D
UAL
U
NITS
O
UTPUT
A O
NLY
(See trim tables on page 4)
5V Dual Sense Adjust:
Max. 5.40 V
R
EXTERNAL
= 30 (
Vdesired - 5
)
0.675 - 0.125 Vdesired
R
ADIATION
H
ARDENED
The SMRT DC/DC converters are designed to provide continuous
normal operation through radiation levels associated with space
missions and in tactical and strategic military environments. The
converters will operate normally in radiation environments with up
to 1 x 10
12
neutrons per square centimeter neutron fluence,
10
11
rads(Si) per second dose rate, and 3x10
5
rads(Si) total
dose. These levels of radiation tolerance make the SMRT
converters suitable for electronics in programs where operation in
high radiation environments is required.
At the highest dose rate (10
11
rads(Si)/sec dose rate) there
will be an upset resulting in a dip in the voltage. This is non-
destructive to the unit. The converter will operate through the
upset.
12V Dual Sense Adjust:
Max. 12.48 V
R
EXTERNAL
= 600 (
5 x Vdesired - 60.42
)
156 - 12.5Vdesired
15V Dual Sense Adjust:
Max 15.36 V
R
EXTERNAL
= 600 (
Vdesired - 15
)
38.4 - 2.5Vdesired
www.craneae.com
Page 2 of 17
Rev B – 20080213
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters
28 VOLT INPUT – 35 WATT
Input Voltage Range
• 19 to 56 VDC continuous
Output Power
• up to 35 watts depending on model
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
Power Dissipation (Pd)
• 20 to 28 W
Output Voltage Temperature Coefficient
• 100 ppm/°C max
Current Limit
• 125% of full load typical
Isolation
• 100 megohm minimum at 500 V
Audio Rejection
• 50 dB typical
Conversion Frequency
• 300 kHz typical, 270 kHz min., 330 kHz max.
Radiation (will operate through)
• 1x10
12
neutrons/cm
2
neutron or proton fluence
• Radiation dose rate 10
11
rads (Si) /sec
• Total dose up to 300 K rads (Si)
• SEU 60 MeV-cm
2
/mg
Cross Regulation
• 2.5% typical
• Applies to -V
O
AUX on triple models only
• Variation of -V
O
AUX from +P
O
=80%, -P
O
=20%
to +P
O
=20%, -P
O
=80%
• Referenced to 50%/50% balanced ±V
O
AUX loads
OPERATING CONDITIONS AND CHARACTERISTICS
SYNC AND INHIBIT
Sync In 270-330 kHz typical
• Duty cycle 20% min, 80% max
• 2.5V p-p minimum amplitude
• 10V p-p maximum amplitude
• Can be referenced to input or output return
• If sync is used at lower end of the range, full load
operation is not guaranteed.
Inhibit
• Actve low (output disabled)
INH referenced to input common
Active low 0.4 V max
Inhibit pin current < 2mA
• Open collector (output enabled)
High >3.0V
Not to exceed 10V
Open Collector
Inhibit Pin Voltage
• 5 to 6 V
MECHANICAL AND ENVIRONMENTAL
Size (maximum)
2.705 x 2.205 x 0.400 inches (68.71 x 56.01 x 10.16 mm)
See case S for dimensions.
Weight (maximum)
100 grams maximum
Screening
Space Prototype, Class H, or Class K
Radiation tolerant to Radiation Hardness Assurance (RHA) levels of “-” (O), “P”, “R”, or “F” per MIL-PRF-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 “Class H and K, MIL-PRF-38534 Screening” tables for more information.
Available configurations: OO, HP, HR, KP, KR, KF
www.craneae.com
Page 3 of 17
Rev B – 20080213
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters
28 VOLT INPUT – 35 WATT
TRIM TABLES
T
RIM DOWN
Singles
R
TRIM
should be connected between the
Trim
pin and
Positive Sense
pin.
Duals
R
TRIM
should be connected between the
Trim B
pin and
Positive Vout
B
pin. This only trims output B, output A can use the sense pin to trim up
only.
Triples
R
TRIM
should be connected between the
Trim A
pin and
Positive Vout
A
pin to adjust the Main output.
R
TRIM
should be connected between the
Trim B
pin and
Positive Vout
B
pin to adjust the Auxiliary outputs.
R
TRIM
Vout - Vmin
=K(
)
Vnom - Vout
1
2
3
4
5
SMRT Single
14
13
Trim 12
11
10
9
Sense 8
1
2
3
4
5
SMRT Dual
14
Vout B 13
Trim B 12
11
10
9
8
1
2
3
4
5
SMRT Triple
14
Vout A 13
Trim A 12
+Vout B 11
10
9
Trim B 8
Vout = Desired Voltage; K/Vmin/Vnom come from table below.
F
IGURE
1: T
RIM
D
OWN
D
IAGRAMS
V
NOM
3.3
5.0
12
15
K
3500
4520
11030
12900
V
MIN
3.18
4.16
7.05
7.65
% OF
RATED
96
83
58
51
T
RIM
U
P
Singles
R
TRIM
should be connected between the
Trim
pin and
Sense Return
pin.
Duals
R
TRIM
should be connected between the
Trim B
pin and
Vout B Return
pin. This only trims output B, output A can use the sense pin to trim up
only.
Triples
R
TRIM
should be connected between the
Trim A
pin and
Vout A Return
pin
to adjust the Main outputs.
R
TRIM
should be connected between the
Trim B
pin and
Vout B Return
pin
to adjust the Auxiliary outputs.
1
2
3
4
5
SMRT Single
14
13
Trim 12
11
10
Sense Return 9
8
1
2
3
4
5
SMRT Dual
Vout B Return 14
13
Trim B 12
11
10
9
8
R
TRIM
= K (
Vmax - Vout
)
Vout - Vnom
Vout = Desired Voltage; K/Vmax/Vnom come from table below.
1
2
3
4
5
SMRT Triple
14
Vout A Return 13
Trim A 12
11
Vout B Return 10
9
Trim B 8
V
NOM
3.3
5.0
12
15
K
3000
3000
5300
5300
V
MIN
3.70
6.26
14.69
18.54
% OF
RATED
112
125
122
124
MIN V
IN
22
22
19
22
F
IGURE
2: T
RIM
U
P
D
IAGRAMS
www.craneae.com
Page 4 of 17
Rev B – 20080213
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters
28 VOLT INPUT – 35 WATT
PIN OUT
Pin
1
2
3
4
5
8
9
10
11
12
13
14
Single Output
Vin
Vin Return
Inhibit
Sync In
Sync Return
Sense
Sense Return
Vout A Return
Vout A
Trim
Vout A
Vout A Return
Dual Output
Vin
Vin Return
Inhibit
Sync In
Sync Return
Sense A
Sense A Return
Vout A Return
Vout A
Trim B
Vout B
Vout B Return
Triple Output
Vin
Vin Return
Inhibit
Sync In
Sync Return
Trim B
Vout B Neg.
Vout B Return
Vout B Pos.
Trim A
Vout A
Vout A Return
1
2
3
4
5
See case S for dimensions.
14
13
TOP VIEW
12
11
10
9
8
F
IGURE
3: P
IN
O
UT
www.craneae.com
Page 5 of 17
Rev B – 20080213
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