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 I2S input
(7)
(8)
In Equation 8, M is the unsigned mantissa and E the negative signed exponent. For
example, in word2 bits [14:8] = [0111 010] represent k2' = (7/24)× 2−2 = 1.09375 10
−1.
Section 9.5.4 shows the I2C address locations of the controls for various bands of the
equalizer.
Table 15. Equalizer control word construction
Word Section Data
word1 15 t1
word1 [14:4] 11 mantissa bits of k1’
word1 [3:0] Four exponent bits of k1’
word2 15 t2
word2 [14:11] Four mantissa bits of k2’
word2 [10:8] Three exponents bits of k2’
word2 [7:1] k0
word2 0 s
Fig 6. Transfer functions for several quality factors Q
k1′1k
1
–t11=
1k
1
+t10=
=
k2′1k
2
–t20=
1k
2
+t21=
=
kxM2
E–
⋅M1<
=
010aaa222
4
8
12
Gain
(dB)
0
Frequency (Hz)
101105
104
102103
Q1 = 0.27
Q2 = 0.61
Q3 = 1.65