GE864-QUAD V2 Hardware User Guide
1vv0300841 Rev.5
–
2017-05-11
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights
Reserved.
Page 53 of 77
10.2.2.
Output Lines Characteristics
TIP
:
We suggest driving the load differentially from both output
drivers, thus the output swing will double and the need for
the output coupling capacitor avoided. However if particular
OEM application needs also a
Single Ended circuitry
can be
implemented, but the output power will be reduced four times.
The OEM circuitry shall be designed to reduce the common mode
noise typically generated on the ground plane and to get the
maximum power output from the device (low resistance tracks).
WARNING:
The loads are directly connected to the amplifier outputs when
in
Differential
configuration, through a capacitor when in
Single Ended
configuration. Using a
Single
Ended configuration
, the unused output line must be left open
. Not respecting this constraint, the output stage
will be damaged.
TIP :
Remember that there are slightly different electrical
performances between the two internal audio amplifiers:
the
“
Ear_MT
”
lines
can directly drive a
16
Ω
load
at
–
12dBFS
(**)
in
Differential
configuration
the “
Ear_HF
”
lines can directly drive a
4
Ω
load
in
Differential
configurations
There is no difference if the amplifiers drive an external
amplifier
(**)
0dBFS
is the normalized overall Analog Gain for each
Output channel equal to
3,7V
pp
differential
