Texas Instruments TAS5707 User Manual

(1or0) 2 +´
1
(1or0) 2 +(1or0) 2 +.......(1or0) 2 +.......(1or0) 2´ ´ ´ ´
0 –1 –4 –23
2 Bit
1
2 Bit
0
2 Bit
–1
2 Bit
–4
2 Bit
–23
M0126-01
u
Coefficient
Digit8
u
u u u u
S
x
Coefficient
Digit7
x.
x x x
Coefficient
Digit6
x
x x x
Coefficient
Digit5
x
x x x
Coefficient
Digit4
x
x x x
Coefficient
Digit3
x
x x x
Coefficient
Digit2
x
x x x
Coefficient
Digit1
Fraction
Digit5
Fraction
Digit4
Fraction
Digit3
Fraction
Digit2
Fraction
Digit1
Integer
Digit1
Sign
Bit
Fraction
Digit6
u=unusedordon’tcarebits
Digit=hexadecimaldigit
M0127-01
0
TAS5707, TAS5707A
SLOS556B –NOVEMBER 2008–REVISED NOVEMBER 2009 www.ti.com
The decimal value of a 3.23 format number can be found by following the weighting shown in Figure 33. If the
most significant bit is logic 0, the number is a positive number, and the weighting shown yields the correct
number. If the most significant bit is a logic 1, then the number is a negative number. In this case every bit must
be inverted, a 1 added to the result, and then the weighting shown in Figure 34 applied to obtain the magnitude
of the negative number.
Figure 34. Conversion Weighting Factors—3.23 Format to Floating Point
Gain coefficients, entered via the I
2
C bus, must be entered as 32-bit binary numbers. The format of the 32-bit
number (4-byte or 8-digit hexadecimal number) is shown in Figure 35
Figure 35. Alignment of 3.23 Coefficient in 32-Bit I
2
C Word
Table 2. Sample Calculation for 3.23 Format
db Linear Decimal Hex (3.23 Format)
0 1 8388608 00800000
5 1.7782794 14917288 00E39EA8
–5 0.5623413 4717260 0047FACC
X L = 10
(X/20)
D = 8388608 × L H = dec2hex (D, 8)
Table 3. Sample Calculation for 9.17 Format
db Linear Decimal Hex (9.17 Format)
0 1 131072 20000
5 1.77 231997 38A3D
–5 0.56 73400 11EB8
X L = 10
(X/20)
D = 131072 × L H = dec2hex (D, 8)
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Texas Instruments TAS5707 Specifications

General

Brand	Texas Instruments
Model	TAS5707
Category	Amplifier
Language	English