Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters –
PRELIMINARY
28 VOLT INPUT – 35 WATT
FEATURES
•
•
•
•
•
•
•
–55°C to +125°C operation
19 to 56 VDC input
Dual Magnetic feedback
80 V for 100 ms transient protection
Inhibit function and output trim
Indefinite short circuit protection
Radiation hardened 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 80 MeV cm
2
/mg
•
•
•
•
Meets MIL-STD-704 emergency operation and transient
standards
No minimum load required
5 port isolated design
Isolated synchronization input
MODELS
VDC O
UTPUT
SINGLE
3.3
5
15
DUAL
±5
±12
±15
• Topology – Two-Phased Flyback
TRIPLE
+3.3 & ±12
+5 & ±12
+5 & ±15
DESCRIPTION
The SMRT Series™ of DC/DC converters offers up to 35
watts of power in a radiation hardened 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.
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 topology
and discontinuous topology 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 either a
single main output and dual outputs or a configuration of two
sets of dual outputs with each set independently regulated. Each
set of outputs are electrically isolated from each other and from
the input. This product configuration eliminates cross regulation
effects between output sets. Configurations include:
• Single Output: Two-phased single output
• Dual Output: Dual outputs each with independent regulation and
isolation.
• Triple Output: One main (independent) output and two auxiliary
outputs (±).
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.
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 logic low (≤ 0.8 V) signal is applied to the TTL compatible
inhibit pin. In the inhibit mode the inhibit pin current requirement
is less than ~2 mA. The converter resumes normal operation
when a logic 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
YNCHRONIZATION
An isolated sync input allows this input to be connected to any of
the devices three returns. It can be referred to the input return or
any of the output returns. Input current into this pin is limited by a
series 1k ohm resistance.
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 14
Rev B PRELIMINARY
20060713
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters –
PRELIMINARY
28 VOLT INPUT – 35 WATT
O
UTPUT
V
OLTAGE
T
RIM
The output voltage of each set can be trimmed up or down by as
much as 20% of nominal. 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.”
• Single: One set
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-destruc-
tive to the unit. The converter will operate through the upset.
EMI
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.
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 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. The converter will operate through radiation environments
including: 1x10
12
neutrons/cm
2
, 10
11
rads(Si)/sec 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.
INPUT (for Electrical Output Characteristics see pp. 6-10)
Electrical Characteristics: -55°C to +125°C, 28 VDC Vin, 100% load, unless otherwise specified.
ALL MODELS
PARAMETER
INPUT VOLTAGE
1
CONDITIONS
CONTINUOUS
TRANSIENT
100 ms
MIN
19
0
—
—
—
TYP
28
—
—
—
10
MAX
56
80
100
50
—
UNITS
VDC
V
mA
INPUT CURRENT
NO LOAD
INHIBITED1
INPUT RIPPLE
CURRENT
2
10 kHz - 50 MHz
mA p-p
Notes
1. Converter should not be inhibited or operated below 19 Vin above 5x10
4
rads
(Si) total dose.
2. Converters meet MIL-STD-461 specification revisions for conducted emissions
C-CE03 and D-/E-CE102. The actual value of input ripple current is much less,
the limit in the characteristic table is based on measurement resolution.
www.craneae.com
Page 2 of 14
Rev B PRELIMINARY
20060713
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters –
PRELIMINARY
28 VOLT INPUT – 35 WATT
OPERATING CONDITIONS AND CHARACTERISTICS
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)
• 15 W
Output Voltage Temperature Coefficient
• 100 ppm/°C max
Current Limit
• 120% of full load typical
Isolation
• 100 megohm minimum at 500 V
Audio Rejection
• 50 dB typical
Conversion Frequency
• 300 kHz. typical
Radiation (will operate through)
• Neutron fluence 1x10
12
neutrons/ sq. cm.
• Radiation dose rate 10
11
rads (Si) /sec
• Total dose up to 3x10
5
rads (Si)
• SEU > 80 MeV-cm
2
/mg
SYNC AND INHIBIT
Sync In 225-350 kHz typical
• Duty cycle 20% min, 80% max
• 2.5V minimum amplitude
• 10V p-p maximum amplitude
• Can be referenced to input or output return
Inhibit TTL
• Logic low (output disabled)
INH1 referenced to input common
Logic low 0.8 V max
Inhibit pin current < 2mA
• Logic high (output enabled)
Open collector
Logic high >3.0V
Not to exceed 10V
TTL or Open Collector
Inhibit Pin Voltage (unit enabled)
• 5 to 6 V
MECHANICAL AND ENVIRONMENTAL
Size (maximum)
2.705 x 2.205 x 0.400 inches (68.71 x 56.01 x 38.23 x 10.16 mm)
See case S for dimensions.
Weight (maximum)
100 grams maximum
Screening
Space Prototype, Class H, or Class K
Radiation hardness levels O, R, F
See “Class H and K, QML Screening” tables for more information.
Available configurations: OO, HO, HR, KR, KF
www.craneae.com
Page 3 of 14
Rev B PRELIMINARY
20060713
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters –
PRELIMINARY
28 VOLT INPUT – 35 WATT
PIN OUT
Pin
1
2
3
4
5
8
9
10
11
12
13
14
Single Output
Positive Vin
Vin Return
Inhibit
Sync In
Sync Return
Positive Sense
Sense Return
Vout Return
Positive Vout
Trim
Positive Vout
Vout Return
Dual Output
Positive Vin
Vin Return
Inhibit
Sync In
Sync Return
Positive Sense #2
Sense Return #2
Vout Return #2
Positive Vout #2
Trim #1
Positive Vout #1
Vout Return #1
Triple Output
Positive Vin
Vin Return
Inhibit
Sync In
Sync Return
Trim/Aux.
Negative Aux. Vout
Aux. Vout Return
Positive Aux. Vout
Trim/Out
Positive Main Vout
Main Vout Return
1
2
3
4
5
See case S for dimensions.
14
13
TOP VIEW
12
11
10
9
8
F
IGURE
1: P
IN
O
UT
www.craneae.com
Page 4 of 14
Rev B PRELIMINARY
20060713
Crane Aerospace & Electronics Power Solutions
SMRT Single, Dual and Triple DC/DC Converters –
PRELIMINARY
28 VOLT INPUT – 35 WATT
MODEL NUMBERING KEY
SMRT
Base Model
Input Voltage
Output Voltage
(single or dual Vout for single or dual models
main and aux. Vout for triple models)
Number of Outputs
(S=single, D=dual, T=triple)
Screening
(OO-prototype, HO, HR, KR, KF)
28 512 T / KR
MODEL SELECTION
SMRT28
Base model
V
out
value
number of outputs
screening
Choose one from each of the following rows
V
out
value
Number of outputs
Screening
singles: 3.3, 5, 15
duals: 5,12,15
*triples: 3.312, 512, 515
“R” = decimal point, 3R3 = 3.3VDC
S (single), D (dual), T (triple)
OO - Space prototype, HO, HR, KR, KF
* for triple models “5” indicates the main voltage, “12” or “15” indicate the ± auxiliary voltages.
www.craneae.com
Page 5 of 14
Rev B PRELIMINARY
20060713
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