ACT 861X Series
Radiation Hardened
50 Watt Power Supply Module
Features
s
Advanced
CIRCUIT TECHNOLOGY
www.aeroflex.com
Radiation Environment
q
q
Total Dose 100K Rad (Si)
No SEE or SEU to 20 MeV/cm
2
/mg
-55
o
C to 85
o
C Baseplate Mounting Temperature
s
50W Power Output, +5V, +12V, +15V, -12V and –15V Output Versions Available
s
50V Input Bus
s
Internal EMI Suppression Circuitry designed to meet the requirements of MIL-STD-461C
s
Short Circuit Protected
s
X
LA
Input Undervoltage Shutdown
LE
F
s
Output Overvoltage Shutdown
s
Overtemperature Shutdown
s
Input Shutdown Control
9001
s
Input Synchronization Control
C
E
s
Output Synchronization Control
RT
I
F
I
E
D
s
Output Status Signal
s
Packaging – Non-Hermetic COB in a 3" x 4" x .9" housing with D connector
s
B
A E
RO
S
ISO
I
NC
.
VIN+
VIN-
VO+
VO-
INHIBIT
INPUT
CONTROL
CIRCUITRY
OUTPUT
CONTROL
CIRCUITRY
STATUS
SYNC_IN
SYNC_OUT
IN_COM
OUT_COM
Figure 1 – Block Diagram
eroflex Circuit Technology - Advanced Multichip Modules © SCD861X REV 2 5/16/00
General Description
Aeroflex’s ACT861X series of power supply modules are radiation hardened 50 Watt units
designed for use in space applications. Using a double ended forward topology with synchronous
rectifiers achieves high efficiency, and the use of Chip-On-Board (COB) construction together with
planar magnetics allows Aeroflex to provide space quality components at down-to-earth prices.
The ACT861X series are full featured single output converters, with EMI filtering, short circuit
protection, input undervoltage shutdown, output overvoltage shutdown, overtemperature shutdown,
input shutdown control and synchronization on both input and output sides. Other output voltages
are available upon request.
Aeroflex’s ACT861X series of power supply modules are radiation hardened 50 Watt units
designed for use in space applications. The block diagram shown in Figure 1 uses a two transistor
(double ended) forward topology to minimize voltage stresses on the semiconductors, and
synchronous rectifiers are used to achieve high efficiency. These full featured converters are
intended to be used in the space environment, conduction cooled to a baseplate and
interconnected to the system via a D connector. The converter includes features such as input
undervoltage shutdown, output overvoltage shutdown, overtemperature shutdown, input shutdown
control and synchronization on both input and output sides. No optocouplers are used in the
converter to assure long term total dose hardness.
The ACT861X series is fabricated as an encapsulated Chip-On-Board module in an aluminum
housing. The Outline Drawing is shown in Figure 2.
The input undervoltage shutdown disables the converter when the input bus is below the
minimum specified setpoint. Nominal input current will be the shutdown current specified. This
prevents the converter from generating low output voltages in the event of bus undervoltages and
drawing high input currents when attempting to power the rated load with these low bus input
voltages. When the input bus voltage is above the minimum specified in Table 1 the converter
commences operation.
Overtemperature protection is integral to the ACT861X series. An internal temperature sensor
mounted near the higher power dissipating components shuts the converter off if the mounting
temperature is above the threshold specified in Table 1. When the converter cools off it will turn
back on with no cycling of input power required.
The output overvoltage circuit uses a portion of the output voltage derived to power the internal
logic (the bootstrap supply) to measure indirectly the output voltage. This voltage is sensed, and if it
exceeds a predetermined threshold the converter will cycle at a nominal 100Hz frequency
attempting to restart.
Control of the ACT861X is achieved via the
INHIBIT
pin. This pin may be used as both an internal
temperature monitor and to control the module. When
INHIBIT
is shorted to the
IN_COM
pin the
module is disabled. Nominal current flowing through the
INHIBIT
line at this time is less than 1mA,
and the on/off threshold is 6V above the negative return. When the converter temperature sensor is
at –55°C the
INHIBIT
line will be approximately 8.7V; at 85°C it will be approximately 6.7V. This
affords the user a convenient way to measure the converter internal temperature.
Synchronization may either be referenced to the output ground of the converter or input ground.
When synchronization is referenced to the input ground a low impedance clock waveform,
approximately 50% duty cycle, TTL compatible between 450 and 500KHz, should be applied to the
SYNC_IN
terminal and the
IN_COM
terminal. This will synchronize the switching power converter
although not the feedback oscillator. If it is desired to synchronize both the power converter and
feedback oscillator a low impedance clock waveform, approximately 50% duty cycle, TTL
compatible between 450 and 500KHz, should be applied to the
SYNC_OUT
terminal and the
OUT_COM
terminal.
The
STATUS
output is an open collector signal, active low, referenced to
OUT_COM
that is
asserted when the output voltage is within ±10% of the nominal output voltage.
A
Aeroflex Circuit Technology
2
SCD861X REV 2 5/16/00 Plainview NY (516) 694-6700
Table 1 – Performance Specifications
(T
C
= -55°C to +85°C, V
IN
= +50V DC ±5%, C
L
= 0, Unless otherwise specified)
Parameter
Nominal Output Voltage
Regulation, No Load to Full Load
Stability, Over Operating Temperature
Regulation, Over Line Voltage
Ripple
Output Overvoltage Shutdown
Efficency, at Full Load
Output Current
Output Current Limit
Output Voltage Accuracy
Output Power
Input Voltage
Input Voltage
Input Voltage, Transient
Input EMI
Input Undervoltage Threshold
Input Current, at Full Load
Input Current, at No Load
Input Current, Shutdown Asserted
Input Output Isolation
Switching Frequency
Transient Response
Overshoot
Output Short Circuit Duration
Radiation, Total Dose
Radiation, SEE/SEB
Thermal Shutdown, Case
Operating Temperature, Case
Storage Temperature
ACT8601
+5
0.1
0.1
0.05
50
+5.5
85
10
12
ACT8602
+12
0.05
0.05
0.025
25
+13.2
88
4.2
5
ACT8603
+15
0.05
0.05
0.025
25
+16.5
88
3.3
4
±2
50
40
60
100
Complies with MIL-STD-461C
38.5
1.5
0.15
20
10MΩ at 250V Minimum
200
50% load change, 5% Maximum deviation, returns to regulation band
in 1msec.
At Turn On, Turn Off and Power Failure: None
Will Withstand continious short without damage
100
20
85°C
-55°C to +85°C
-65°C to +125°C
ACT8604
-12
0.05
0.05
0.025
25
-13.2
88
4.2
5
ACT8605
-15
0.05
0.05
0.025
25
-16.5
88
3.3
4
Units
Volts
Volts, Maximum
Volts, Maximum
Volts, Maximum
mVolts RMS,
Maximum
Volts, Maximum
%, Minimum
A
Amperes, Maximum
Amperes, Maximum
%
W, Maximum
Volts, Minimum
Volts, Maximum
Volts, Maximum
for 1 second
–
Volts, Maximum
Amperes, Maximum
Amperes, Maximum
mAmperes, Maximum
–
KHz, Nominal
–
–
–
KRad (Si),
Maximum
MeV/cm
2
/mg,
Maximum
Minimum
–
–
Aeroflex Circuit Technology
3
SCD861X REV 2 5/16/00 Plainview NY (516) 694-6700
Talking
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