Figure 6, Equation 7, Table 15 – NXP Semiconductors TFA9812 User Manual
Page 19: Equation 8, Tfa9812, Nxp semiconductors
TFA9812_2
© NXP B.V. 2009. All rights reserved.
Preliminary data sheet
Rev. 02 — 22 January 2009
19 of 66
NXP Semiconductors
TFA9812
BTL stereo Class-D audio amplifier with I
2
S input
(7)
(8)
In
, M is the unsigned mantissa and E the negative signed exponent. For
example, in word2 bits [14:8] = [0111 010] represent k
2
' = (7/2
4
)
×
2
−
2
= 1.09375 10
−
1
.
shows the I
2
C address locations of the controls for various bands of the
equalizer.
Table 15.
Equalizer control word construction
Word
Section
Data
word1
15
t
1
word1
[14:4]
11 mantissa bits of k
1
’
word1
[3:0]
Four exponent bits of k
1
’
word2
15
t
2
word2
[14:11]
Four mantissa bits of k
2
’
word2
[10:8]
Three exponents bits of k
2
’
word2
[7:1]
k
0
word2
0
s
Fig 6.
Transfer functions for several quality factors Q
k
1
′
1
k
1
–
t
1
1
=
1
k
1
+
t
1
0
=
=
k
2
′
1
k
2
–
t
2
0
=
1
k
2
+
t
2
1
=
=
k
x
M 2
E
–
⋅
M
1
<
=
010aaa222
4
8
12
Gain
(dB)
0
Frequency (Hz)
10
1
10
5
10
4
10
2
10
3
Q1 = 0.27
Q2 = 0.61
Q3 = 1.65