SYSTEM CONNECTOR INTERFACE
24
LZT 123 8020 R1A
Low Level Output Voltage (V
OL
), I
o
= 2mA
0
0.6
V
High Level Input Voltage (V
IH
)
1.93
2.75
V
Low Level Input voltage (V
IL
) 0
0.5
V
Note!
Unused pins can be left floating.
5.2.1
General Protection Requirements
•
All 2.75 V digital inputs will continuously withstand and suffer
no damage in the power-on or power-off condition when
subjected to any voltage from - 0.5 V to 3.47 V (3.3 V + 5 %).
•
All 2.75 V digital outputs will continuously withstand a short
circuit to any other voltage within the range 0 V to 3 V.
•
All analogue outputs will continuously withstand a short
circuit to any voltage within the range 0 V to 3 V.
•
The SIM output signals and the SIMVCC supply will
continuously withstand a short circuit to any voltage within
the range 0 V to 4.1V.
Note!
Although the unit should be able to withstand the higher
voltages the unit should not be driven at the levels as it will
result in failures over time.
5.3 Grounds
Pin Signal
Description
2, 4, 6, 8, 10, 12
DGND
Digital ground
60 AGND
Analogue
ground
There are two ground connections in the radio device, AGND
(analogue ground) and DGND (digital ground). Pin assignments
are shown in the table above.
Note!
AGND and DGND are connected at a single point inside the
radio device. They must
not
be joined together in your
application.
5.3.1
Analogue Ground - AGND
AGND is the return signal, or analogue audio reference, for
ATMS (Audio To Mobile Station) and AFMS (Audio From Mobile
Station). It is connected to the DGND inside the radio device
only. The application must not connect DGND and AGND.
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