STA328 STMicroelectronics, STA328 Datasheet - Page 47

• Manufacturer Part Number: STA328
• Description: DIG AUDIO SYSTEM, 2-CH, 36POWERSSOP
• Manufacturer: STMicroelectronics

Specifications of STA328

• Svhc: No SVHC (15-Dec-2010)
• Package / Case: PowerSO
• Interface: I2C
• No. Of Pins: 36
• Operating Temperature Range: -20°C To +125°C
• Supply Voltage Max: 36V
• Supply Voltage Min: 10V
• Termination: RoHS Compliant
• Interface Type: I2C
• Rohs Compliant: Yes

STA328
7.5
7.6
7.6.1
7.6.2
7.6.3
7.6.4
7.6.5
Calculating 24-bit signed fractional numbers from a dB value
The pre-scale, mixing, and post-scale functions of the STA328 use 24-bit signed fractional
multipliers to attenuate signals. These attenuations can also invert the phase and therefore
range in value from -1 to +1. It is possible to calculate the coefficient to utilize for a given
negative dB value (attenuation) via the equations below.
"
"
"
"
As can be seen by the preceding equations, the value for positive phase 0 dB is 0x7FFFFF
and the value for negative phase 0 dB is 0x800000.
User defined coefficient RAM
Coefficient address register 1 (addr 0x16)
Coefficient b1data register bits 23:16 (addr 0x17)
Coefficient b1data register bits 15:8 (addr 0x18)
Coefficient b1data register bits 7:0 (addr 0x19)
Coefficient b2 data register bits 23:16 (addr 0x1A)
C1B23
C2B23
C1B15
CFA7
C1B7
D7
D7
Non-inverting phase numbers 0 to +1:
Coefficient = round(8388607 * 10
Inverting phase numbers 0 to -1:
Coefficient = 16777216 - round(8388607 * 10
D7
D7
D7
0
0
0
0
0
C1B22
C2B22
C1B14
CFA6
C1B6
D6
D6
D6
D6
D6
0
0
0
0
0
C1B21
C2B21
CFA5
C1B13
C1B5
D5
D5
D5
D5
0
0
D5
0
0
0
C1B20
C2B20
(dB / 20)
C1B4
CFA4
C1B12
D4
D4
D4
D4
0
0
0
0
D4
0
)
C1B19
C2B19
CFA3
C1B3
(dB / 20)
C1B11
D3
D3
D3
D3
0
0
0
0
D3
0
)
User programmable processing
C1B18
C2B18
CFA2
C1B2
D2
D2
D2
C1B10
D2
0
0
0
0
D2
0
C1B17
C2B17
CFA1
C1B1
D1
D1
D1
D1
C1B9
0
0
0
0
D1
0
C1B16
C2B16
CFA0
C1B0
C1B8
D0
D0
D0
D0
D0
0
0
0
0
0
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