Datasheet
Maxim Integrated
│
125
MAX98090 Ultra-Low Power Stereo Audio Codec
www.maximintegrated.com
Figure 28. DRC Compression Ratio and Threshold
Figure 29. DRC Expansion Ratio and Threshold
sum of the digital gain/level control, parametric equalizer
gain, and the DRC make-up gain must not exceed 0dB
total. Figure 27 shows the effect of enabling the DRC with
and without digital make-up gain.
The DRC features two programmable signal thresholds.
The high amplitude compression threshold is used to
reduce the maximum sustained signal amplitude. The
compression ratio can be set to one of five options from
a 1:1 ratio to an infinite:1 ratio (or flat output amplitude as
input amplitude increases). The compression threshold
can be configured from -31dB to 0dB. The compression
ratios and a range of thresholds are illustrated in Figure 28.
The low amplitude expansion threshold is used to prevent
background noise from being amplified. When the signal
level drops below the expansion threshold, the DRC
reduces the gain until the signal increases above the
threshold. The expansion ratio can be set to a 1:1, 1:2, or
1:3 ratio while the threshold can be configured from -35dB
INPUT AMPLITUDE (dBFS)
OUTPUT AMPLITUDE (dBFS)
DRC ENABLED
-60 -50 -40 -30 -20 -10 0 -60 -50 -40 -30 -20 -10 0 -60 -50 -40 -30 -20 -10 0
FULL SCALE FULL SCALE
RATIO OPTION
FULL SCALE
THRESHOLD OPTIONS
COMPRESSION
RATION = 4:1
0dB
-5dB
-10dB
-15dB
-20dB
-25dB
-30dB
-60
-50
-40
-30
-20
-10
0
INPUT AMPLITUDE (dBFS)
OUTPUT AMPLITUDE (dBFS)
-60
-50
-40
-30
-20
-10
0
INPUT AMPLITUDE (dBFS)
OUTPUT AMPLITUDE (dBFS)
-60
-50
-40
-30
-20
-10
0
COMPRESSION THRESHOLD
COMPRESSION RATIO
1:1
1:5:1
2:1
4:1
INF:1
COMPRESSION
THRESHOLD = -30dB
RATIO =4:1
COMPRESSION
THRESHOLD = - 30dB
EXPANSION RATIO EXPANSION THRESHOLD
INPUT AMPLITUDE (dBFS)
OUTPUT AMPLITUDE (dBFS)
-30
DRC ENABLED
-90
-50
-70
-90 -80
-40
-60
-80
EXPANDER
THRESHOLD = -60dB
RATIO = 1:2
OUTPUT AMPLITUDE (dBFS)
EXPANSION
THRESHOLD = -60dB
RATIO
OPTIONS
1:1 1:2 1:3
OUTPUT AMPLITUDE (dBFS)
EXPANSION
RATIO = 1:2
THRESHOLD
OPTIONS
-65dB
-70 -60 -50 -40 -30
INPUT AMPLITUDE (dBFS)
-30
-90
-50
-70
-90 -80
-40
-60
-80
-70 -60 -50 -40 -30
INPUT AMPLITUDE (dBFS)
-30
-90
-50
-70
-90 -80
-40
-60
-80
-70 -60 -50 -40 -30
-60dB
-55dB
-50dB
-45dB
-40dB
-35dB