sta5150 STMicroelectronics, sta5150 Datasheet - Page 8

• Manufacturer Part Number: sta5150
• Description: 200w Mono Bash Power Amplifier
• Manufacturer: STMicroelectronics

STA5150
Gain without compression (G)
Max Attenuation ratio
The following graph gives the representation of the Compressor activation status related to the Vthreshold and
the input voltage. The delimitation line between the two fields, compression or not, is expressed by the formula :
Where G is the preamplifier gain without compression.
In the compression region the gain of the preamplifier will be reduced
(G = 2·Vthreshold/Vin) to maintain at steady state the output voltage equal 2*|Vthreshold| .
Instead in the other region the compressor will be off (G = 5).
The delimitation line between the two fields can be related to the output voltage of the preamplifier: in this case
the formula is :
Figure 1. Compressor activation field
The relative attenuation introduced by the variable gain cell is the following :
The total gain of the stage will be:
The maximum input swing is related to the value of input resistor, to guarantee that the input current remain
under Iin_Max value (1 mA).
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D01AU1264
V
IN
8
6
4
2
PEAK
= 5
= 26 dB
Attenu atio n
1
COMPRESSION
Gdb = 20log5 + Attenuation
V
V
o ut
2
in
G < 5
=
=
R
i
2 Vthresh old
------------------------------------------ -
2 Vthre sho ld
3
=
V
--------------------- -
I
in_max
20
in_peak
log
4
G
2
-- -
5
--------------------- -
V
5
in _peak
V
G = 5
th
|Vthreshold|