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Iridium Satellite LLC
9601 SBD Transceiver Product Developers Guide
V1.24 120505
3.2 DC Power Interface
The DC power interface is comprised of the DC power inputs and a control signals as summarized in
Table 7. The three +5V Inputs and three 0V supply returns are used to supply DC power to the 9601 and
ensure that enough current can be drawn across the connector without the 9601 malfunctioning during
transmit due to lack of current supply. Note that all six pins should be connected.
The DC power supply requirements for the 9601 are summarized in Table 8 below. Note that these
requirements apply to DC power measured at the 9601 multi-interface connector input and not at the
output of the power supply. Long power supply cables can cause a voltage drop sufficient to cause the
voltage to be out of specification at the physical power supply input to the 9601.
Input Standby Current (average)
Peak Transient Current –Transmit
Current Average* –when SBD message transfer in process
Average Power consumption –when SBD message transfer in process
* Note: The average power consumption depends on the view of the satellite constellation from the
antenna.
The external power supply needs to guarantee the following:
The supply voltage droop over an 8.3mS burst should not be more than 0.2 Volts.
The power supply should limit the in-rush current to 4 Amps maximum
The supply noise should be less than that in the following profile (linear interpolation between these
points):
100 mV pk-pk 0Hz to 50 kHz
5 mV pk-pk in 50 kHz bandwidth at 1 MHz
10 mV pk-pk in 1 MHz bandwidth at 1 MHz
5 mV pk-pk in 1 MHz bandwidth above 5 MHz.
Note that any cable used to supply power to the transceiver can be no longer than 152mm (6 inches)
from the power source to the connector.
3.2.1 Power On/Off Control
An external on/off input is provided on a pin of the multi-interface connector. The 9601 starts up when
power is applied and the power on/off input is high. As long as the input voltage is applied, logic high on
this line turns the transceiver on and a logic low turns it off. If this line is not required then it must be
connected directly to the +5 V supply. The input logic high threshold is 2.0 V and the logic low threshold is
0.5 V.
Note that this on/off control is not the same as the 9522 or 9522A.
Iridium Satellite LLC Proprietary & Confidential Information
Information contained herein is subject to change without further notice
Table 8: DC Power Input Specifications
Parameter
Main Input Voltage Range
Main Input Voltage Nominal
Main Input Voltage –Ripple
Consumption at +5.0 VDC
Value
+4.5 VDC to +5.5 VDC
5.0VDC
40 mV pp
Value
66mA
1.5 A
<= 350 mA
<= 1.75 W
18
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