STEPPII-55/56-LT H
ARDWARE
DESCRIPTION
V
ERSION
1.01
6 STEPPII-55/56-LT APPLICATION INTERFACE
6.1 Power supply
The power supply for the STEPPII-55/56-LT terminal has to be a single voltage source
of V
VC+
= +10.8 V...+32.0 VDC. It must be able to provide sufficient current in a
transmit GSM burst which typically rises to 1.6 A. The operating voltage (V
VC+
and
GND) is protected from reverse pole connection as long no ground antenna and/or
an AMP connector is NOT connected to the STEPPII-55/56-LT.
All the key functions for supplying power to the device are handled by an ASIC
power supply. The ASIC provides the following features:
Stabilizes
the supply voltages for the GSM base band using low drop linear
voltage regulators.
Controls the module power up and power down procedures.
A watchdog logic implemented in the base band processor periodically
sends signals to the ASIC, allowing it to maintain the supply voltage for all
digital components of STEPPII-55/56-LT GSM/GPRS core. Whenever the
watchdog pulses fail to arrive constantly, the terminal is turned off.
Provides power to the SIM interface, digital outputs and handsfree set.
Keep in mind that, operating voltage (V
VC+
) has to be permanently applied to the
terminal, because of several STEPPII-55/56-LT components such as digital outputs and
handsfree-set do not operate only from the external battery. These components are
operational as long as the main power (V
VC+
) is applied to the STEPPII-55/56-LT
terminal.
6.1.1 Power up/down scenarios
In general, be sure not to turn on the STEPPII-55/56-LT terminal module while it is out of
the operating range of voltage and temperature stated in Table 11
and Table 4. The
STEPPII-55/56-LT terminal would immediately switch off after having started and
detected these inappropriate conditions.
6.1.2 Power supply pins (14, 15 and 16) on the 16-pin connector
One VC+ pin of the 16-pin connector is dedicated to connect the supply voltage, 3
GND pins are recommended for grounding.
The BAT ON/OFF pin serves for charging the internal Li-Ion battery.
Signal name
I/O
Parameter
Description
VC+
I
+10.8 V...+32.0 VDC, I
typ
≤ 1.6 during
transmit burst. The minimum operating
voltage must not fall below +10.0
VDC, not even in case of voltage drop.
Positive operating voltage.
GND
-
0 V
Ground
BAT ON/OFF
I
Pull to ground (GND) to charge the
internal Li-Ion battery. Leave it open to
stop charging.
Except ground planes, newer connect this line to
any power supply voltage.
6.1.3 Automatic shutdown
Automatic shutdown takes effect if:
•
the STEPPII-55/56-LT board is exceeding the critical limits of over or under
temperature.
This confidential document is a property of FALCOM and may not be copied or circulated without previous permission
.
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