Datasheet

Maxim Integrated │ 128
MAX98090 Ultra-Low Power Stereo Audio Codec
www.maximintegrated.com
Table 56. Dynamic Range Control (DRC) Expander Register
Playback Path Digital Filters
The playback path DSP includes a digital filter stage. One
filter, set with the MODE bit (Table 57), offers the choice
between the IIR voice filters and the FIR music filters.
The IIR filters are optimized for standard (f
S
= 8kHz) and
wideband (f
S
= 16kHz) voice applications, while the FIR
filters are optimized for low power operation at higher
audio/music sampling rates. For sampling rates in excess
of 50kHz (f
LRCLK
> 50kHz), the FIR audio filters must
be used, and the DHF bit should be set to appropriately
scale the FIR interpolation filter. The MODE configuration
selected applies to both channels of both the record and
playback path DSP.
The playback path DSP also features a DC-blocking filter.
This filter can be used with both the IIR voice and FIR
music filters, and blocks low-frequency (including DC)
input signals outside of the lower end of the audio band.
Digital-to-Analog Converter (DAC)
Conguration
The stereo DAC architecture includes two independent
audio paths, analog outputs that can be routed to any
of the analog output mixers, and two operating modes
(Table 4). One operating mode is optimized for maximum
dynamic performance while the other is optimized for
lower power consumption. Both DAC channels can be
enabled independently, allowing the device to support
both stereo and left or right mono configurations (Table 8).
ADDRESS: 0x35
DESCRIPTION
BIT NAME TYPE POR
7 — — — —
6
DRCEXP[2:0] R/W
0
PLAYBACK DRC Expansion Ratio Conguration
0x0: 1:1 0x2: 1:3
0x1: 1:2 0x3–0x7: Reserved
5 0
4
DRCTHE[4:0] R/W
0
PLAYBACK DRC Expansion Threshold Conguration
3 0
0x00: -35dB
0x01: -36dB
0x02: -37dB
0x03: -38dB
0x04: -39dB
0x05: -40dB
0x06: -41dB
0x07: -42dB
0x08: -43dB
0x09: -44dB
0x0A: -45dB
0x0B: -46dB
0x0C: -47dB
0x0D: -48dB
0x0E: -49dB
0x0F: -50dB
0x10: -51dB
0x11: -52dB
0x12: -53dB
0x13: -54dB
0x14: -55dB
0x15: -56dB
0x16: -57dB
0x17: -58dB
0x18: -59dB
0x19: -60dB
0x1A: -61dB
0x1B: -62dB
0x1C: -63dB
0x1D: -64dB
0x1E: -65dB
0x1F: -66dB
2 0
1 0
0 0