PD-97819
HIGH RELIABILITY,
RADIATION TOLERANT,
LOW POWER,
DC-DC CONVERTER
Description
The D-Series of DC-DC converters are low power
radiation tolerant, high reliability devices designed for
hostile radiation environments such as those
encountered by geostationary earth orbit satellites, deep
space probes and communication systems. Features
include small size, high efficiency, low weight, and a
good tolerance to total ionizing dose, single event
effects, and environmental stresses such as temperature
extremes, mechanical shock, and vibration. All
components are fully derated to meet the requirements
of EEE-INST-002 and MIL-STD-1547B. Extensive
documentation including worst case analysis, radiation
susceptibility, thermal analysis, stress analysis, and
reliability analysis are available.
The D-Series converters have two outputs, each is
independently regulated. Two versions exist; One
version providing two positive outputs and one version
providing one negative and one positive output. The D-
Series converters incorporate a fixed frequency flyback
power converter and internal EMI filter that meets the
requirements for most major satellite power buses. The
converters can be remotely turned on and off via an
inhibit pin. Additional inhibit pins are also included to
control the outputs individually. This feature facilitates
turn-on outputs sequencing if desired. Each converter
is encased in a cold rolled steel hermetic package. The
package measures 1.80"L x 1.40"W x 0.42"H and
weighs less than 55 grams. The package utilizes rugged
ceramic feed-through copper pins and is hermetically
sealed using parallel seam welding. Two package
options are available. Please refer to page 9 for I/O
configurations.
Environmental screening includes temperature cycling,
constant acceleration, fine and gross leak, and burn-in
as specified by MIL-PRF-38534 for class H hybrids.
Non-flight versions of the D-Series converters are
available for system development purposes. Variations
in electrical specifications and screening to meet custom
requirements can be accommodated.
D28XXD-SERIES
28V Input, Regulated Dual Outpu
ts
Features
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Total Dose > 50K Rad(Si)
SEE > 40MeV
.
cm
2
/mg
Low Weight < 55 grams
18V to 50V DC Input Range
Up to 10W Output Power
Independently Regulated Outputs:
±
5V,
±
12V and
±
15V
-55°C to +125°C Operating Temperature Range
100M
Ω
@ 100VDC Isolation
Input Under-Voltage Protection
Meets Conducted Emission Requirements
of Most Major Power Buses:
100Hz - 100KHz: 80dBµArms
100KHz - 10MHz: Log-linear Decrease
10MHz - 50MHz: 40dBµArms
Short Circuit and Overload Protection
Meets the Derating Requirments of
EEE-INST-002 and MIL-STD-1547B
Synchronization Input / Output
On/Off Control via Converters’s Inhibit Pin
and Individual Output’s Inhibit Pin
High CS Damping
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Applications
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Launch Vehicles
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Communication Systems
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Geostationary or Low Earth Orbit Satellites
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1
02/12/14
D28XXD-SERIES
(28V Input, Regulated Dual Outputs)
Circuit Description
The D-Series DC-DC converters utilize two-stage
regulation with a flyback topology with a switching
frequency of 250KHz for primary regulation and linear
post regulation in the secondary for each of the
outputs.
Output power is limited under any load fault
condition to approximately 110% of rated output.
An overload condition causes the converter output
to behave like a constant current source with the
output voltage dropping below nominal. The
converter will resume normal operation when the
load current is reduced below the current limit point.
This protects the converter from both overload and
short circuit conditions. There are no latching
elements to eliminate the possibility of falsely
triggering the protection circuits during single event
radiation exposure.
An under-voltage protection circuit prohibits the
converter from operating when the line voltage is
too low for safe operation. The converter will not
start until the line voltage rises to approximately 16V.
An inhibit pin is provided to control converter operation.
This inhibit pin is intended for operation with an open
collector transistor drive or a relay closure to the
input return. The pin may be left open for normal
operation and has a nominal open circuit voltage of
4V. Also provided are the individual output on/off
control pins (Pin 10-Output 1 Inhibit and Pin 9-Output
2 Inhibit).
Synchronization input pin is included allowing
multiple converters to operate at a common switching
frequency. Converters can be synchronized to a
common frequency with an external clock. This may
be used to eliminate beat frequency noise or to avoid
generating noise at certain frequencies for noise
sensitive systems.
Design Methodology
The D-Series is developed using a proven conservative
design methodology, which includes selecting
radiation tolerant and established reliability
components and fully derating to the requirements
of EEE-INST-002 and MIL-STD-1547B. Heavy
derating of the radiation-hardened power MOSFET
virtually eliminates the possibility of SEGR and SEB.
2
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D28XXD-SERIES
(28V Input, Regulated Dual Outputs)
Specifications
Absolute Maximum Ratings
Input voltage range
Output power
Lead temperature
Storage temperature
Internally limited
+300°C for 10sec
-55°C to +135°C
Recommended Operating Conditions
-0.5Vdc to +60Vdc Input voltage range (Note 13)
Output power
Operating temperature
Operating temperature,
derated (Note 13)
18Vdc to 50Vdc
0 to Max. Rated
-55°C to +125°C
-55°C to +73°C
Operating case temperature (Note 12) -55°C to +125°C
Electrical Performance Characteristics
Parameter
Group A
Subgroup
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 28V DC ± 5%, C
L
= 0
unless otherwise specified
Limits
Min
18
Nom
28
Max
50
Unit
Input voltage (V
IN
)
Output voltage (V
OUT
)
D2805D
D2812D
D2815D
D2805D
D2812D
D2815D
Output power (P
OUT
)
D2805D
D2812D
D2815D
Output current (I
OUT
)
D2805D
D2812D
D2815D
Line regulation (VR
LINE
)
1,2,3
V
IN
= 18, 28, 50V
I
OUT
= 0%, 50%, 100% rated
Load regulation (VR
LOAD
)
1,2,3
I
OUT
= 0%, 50%, 100% rated
V
IN
= 18, 28, 50V
Cross regulation (VR
CROSS
)
D2805D
D2812D
D2815D
Input current (I
IN
)
D2805D
D2812D
D2815D
Switching frequency (F
S
)
1,2,3
1,2,3
Pin 6 connected to Pin 2
Sync. Input (Pin 4) open
I
OUT
= 0, Pin 6 open
1,2,3
V
IN
= 18, 28, 50V, Note 1
1,2,3
V
IN
= 18, 28, 50V, Note 2
Either Output
1,2,3
1
1
1
2.3
2,3
2,3
I
OUT
= 100% rated load
Note 4, 14
I
OUT
= 100% rated load
Note 4
V
±4.95
±11.88
±14.85
±4.85
±11.64
±14.70
±5.00
±12.00
±15.00
±5.05
±12.12
±15.15
±5.15
±12.36
±15.15
V
V
V
IN
= 18, 28, 50V, Note 2
Either Output
0
0
0
5.0
5.0
5.0
W
0
0
0
1.00
0.42
0.33
A
-0.05
0.05
%
-1.0
1.0
%
5.0
5.0
5.0
mV
35
35
35
10
225
250
275
kHz
mA
For Notes to Electrical Performance Characteristic Table, refer to page 5
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3
D28XXD-SERIES
(28V Input, Regulated Dual Outputs)
Electrical Performance Characteristics
Parameter
Group A
Subgroup
(continued)
Limits
Unit
Min
Nom
Max
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 28V DC ± 5%, C
L
= 0
unless otherwise specified
Synchronization input
Frequency range
Pulse high level
Pulse low level
Pulse transition time
Pulse duty cycle
Output ripple (V
RIP
)
D2805D
D2812D
D2815D
Output ripple @ switch
frequency
D2805D
D2812D
D2815D
Efficiency (E
FF
)
D2805D
D2812D
D2815D
Inhibit input
Open circuit voltage
Drive current (sink)
Voltage range
Current limit point
D2805D
D2812D
D2815D
Power dissipation load fault
(P
D
)
Output response to
step load changes (V
TLD
)
D2805D
D2812D
D2815D
Recovery time,
step load changes (T
TLD
)
D2805D
D2812D
D2815D
Recovery time,
step line changes (T
TLN
)
4,5,6
18V to/from 50V
I
OUT
= 100% rated load, Notes 1, 7, 8
4,5,6
Half Load to/ from Full Load, Note 6
-15
-15
-15
15
15
15
mV pk
1,2,3
Short Circuit, Overload, Note 5
1,2,3
V
OUT
= 90% of Nominal
Note 10
105
105
105
145
145
145
8.0
W
%
Note 1
4.0
600
50
V
µA
V
1,2,3
I
OUT
= 100% rated load
1,2,3
V
IN
= 18, 28, 50V
I
OUT
= 100% rated load
Note 1
0.5
0.5
0.5
1.0
1.0
1.0
mV rms
1,2,3
V
IN
= 18, 28, 50V
I
OUT
= 100% rated load
Note 3
20
20
20
mV p-p
1,2,3
External clock on sync In (Pin 4),
Note 1
450
2.5
-0.5
40
20
80
550
5.0
0.5
kHz
V
V
V/µs
%
55
61
62
58
64
65
%
4,5,6
Half Load to/from Full Load,
Notes 6, 7
500
500
500
100
µs
µs
For Notes to Electrical Performance Characteristic Table, refer to page 5
4
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D28XXD-SERIES
(28V Input, Regulated Dual Outputs)
Electrical Performance Characteristics
Parameter
Group A
Subgroup
(continued)
Limits
Unit
Min
Nom
Max
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 28V DC ± 5%, C
L
= 0
unless otherwise specified
I
OUT
= 100% rated load
No effect on DC performance
Notes 1, 4
Each output
10% Load, Full Load
Note 9
Capacitive load (C
L
)
D2805D
D2812D
D2815D
Turn-on response
overshoot (V
OS
)
D2805D
D2812D
D2815D
Turn-on delay (T
DLY
)
Enable input (Inhibit)
open circuit voltage
Drive current (sink)
Voltage range
EMC conducted
susceptibility
(Line rejection)
Electromagnetic Interference
(EMI), conducted emission
(CE)
Isolation
Device Weight
MTBF
1
220
33
33
µF
4,5,6
25
25
25
10
1,2,3
Note 1
0
1
I
OUT
= 100% rated load
Primary power sine wave injection of
2Vp-p, 100Hz to 50MHz, Note 1
I
OUT
= 100% rated load, Note 1
Input to Output or Any Pin to Case
except Pin 3, test @ 100 VDC
100
55
MIL-HDBK-217F2, SF, 35°C
100.000
80
90
10
100
0.4
ms
V
µA
V
dB
mV
1
1
Limits per Fig. 1
MΩ
g
Hours
Notes: Specification and Electrical Performance Characteristics
1.
2.
3.
4.
Parameter is tested as part of design characterization or after design changes. Thereafter, parameter shall be
guaranteed to the limits specified.
Parameter verified during line and load regulation tests.
Guaranteed for a D.C. to 20 MHz bandwidth. Tested using a 20 kHz to 10 MHz bandwidth.
Capacitive load may be any value from 0 to the maximum limit without compromising dc performance.
A capacitive load in excess of the maximum limit may interfere with the proper operation of the converter’s overload
protection, causing erratic behavior during turn-on.
Overload power dissipation is defined as the device power dissipation with the load set such that V
OUT
= 90% of
nominal.
Load step transition time > 100
µs
Recovery time is measured from the initiation of the transient to where V
OUT
has returned to within ±1% of its steady
state value.
Line step transition time > 100
µs.
Turn-on delay time from either a step application of input power or a logic low to a logic high transition on the Inhibit
Pin (Pin 6) to the point where V
OUT
= 90% of nominal.
Current limit point expressed as a percentage of full rated load current.
For models with two positive outputs the envelope specification for the design is that each output voltage is limited to
the range 1V to 5V.
Although operation at temperatures between +85°C and +125°C is guaranteed, no parameter limits are specified.
Meets the derating requirements of EEE-INST-002 and MIL-STD-1547B – except for ceramic capacitors with voltage
stress below 10V will minimum be rated at 50V.
End of life is + 3%
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
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