Datasheet

Maxim Integrated │ 123
MAX98090 Ultra-Low Power Stereo Audio Codec
www.maximintegrated.com
Table 52. Parametric Equalizer Band N (1–7) Biquad Filter Coefficient Registers
The parametric equalizer coefficients are uninitialized at
power-up, and when used the coefficients should be pro-
grammed before the device and equalizer are enabled.
The transfer function for each band is defined as:
12
01 2
12
01 2
B BZ B Z
H(z)
A AZ A Z
−−
−−
+× + ×
=
+× + ×
The biquad filter in each band has 5 user programmable
coefficients (B
0
, B
1
, B
2
, A
1
, and A
2
), and each individual
coefficient is 3 bytes (24 bits) long (A
0
is fixed at 1). They
occupy 15 consecutive registers per band for a total
of 105 consecutive registers for all 7 bands (Table 52).
Each set of three registers (per coefficient) must be pro-
grammed consecutively for the settings to take effect. The
coefficients are stored using a two’s complement format
where the first 4 bits are the integer portion and the last 20
bits are the decimal portion (which results in an approxi-
mate +8 to -8 range for each coefficient).
ADDRESS RANGE (BY BAND)
NAME TYPE COEFFICIENT SEGMENT
1 2 3 4 5 6 7
0x46 0x55 0x64 0x73 0x82 0x91 0xA0
Equalizer Band N
Coefcient B0
R/W B0_N[23:16]
0x47 0x56 0x65 0x74 0x83 0x92 0xA1 R/W B0_N[15:8]
0x48 0x57 0x66 0x75 0x84 0x93 0xA2 R/W B0_N[7:0]
0x49 0x58 0x67 0x76 0x85 0x94 0xA3
Equalizer Band N
Coefcient B1
R/W B1_N[23:16]
0x4A 0x59 0x68 0x77 0x86 0x95 0xA4 R/W B1_N[15:8]
0x4B 0x5A 0x69 0x78 0x87 0x96 0xA5 R/W B1_N[7:0]
0x4C 0x5B 0x6A 0x79 0x88 0x97 0xA6
Equalizer Band N
Coefcient B2
R/W B2_N[23:16]
0x4D 0x5C 0x6B 0x7A 0x89 0x98 0xA7 R/W B2_N[15:8]
0x4E 0x5D 0x6C 0x7B 0x8A 0x99 0xA8 R/W B2_N[7:0]
0x4F 0x5E 0x6D 0x7C 0x8B 0x9A 0xA9
Equalizer Band N
Coefcient A1
R/W A1_N[23:16]
0x50 0x5F 0x6E 0x7D 0x8C 0x9B 0xAA R/W A1_N[15:8]
0x51 0x60 0x6F 0x7E 0x8D 0x9C 0xAB R/W A1_N[7:0]
0x52 0x61 0x70 0x7F 0x8E 0x9D 0xAC
Equalizer Band N
Coefcient A2
R/W A2_N[23:16]
0x53 0x62 0x71 0x80 0x8F 0x9E 0xAD R/W A2_N[15:8]
0x54 0x63 0x72 0x81 0x90 0x9F 0xAE R/W A2_N[7:0]