MAX98090AETL+ Maxim Integrated, MAX98090AETL+ Datasheet - Page 122

• Manufacturer Part Number: MAX98090AETL+
• Description: Interface - CODECs 5V 130mW Stereo Headphone Amp
• Manufacturer: Maxim Integrated

Specifications of MAX98090AETL+

• Rohs: yes

MAX98090
Figure 30. DRC Attack and Release Time Waveforms
The DRC provides a wide range of programmable attack
and release times (Table 53). When the compression
is enabled and the signal amplitude increases until the
compression threshold is exceeded, the attack time
determines how quickly the selected compression ratio
is applied. When the signal amplitude decreases and the
compression threshold would no longer be exceeded, the
release time determines how quickly the gain returns to
normal (Figure 30).
When expansion is enabled and the signal amplitude
decreases until it drops below the expansion threshold,
the release time determines how quickly the selected
expansion ratio is applied. When the signal amplitude
increases and the expansion threshold would no longer
be exceeded, the attack time determines how quickly the
gain returns to normal.
The attack and release times are not absolute. They are
instead used to set the rate at which the gain is adjusted
once the signal amplitude is either above or below the
appropriate threshold. Therefore the selected attack/
release times are relative to the ratio of the new signal
amplitude to the selected compression and expansion
thresholds. The values provided in Table 53 all assume
the input signal amplitude changed to exceed the appro-
priate threshold by a ratio of 12dB (above for compression
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COMPRESSION
THRESHOLD
AMPLITUDE
INCREASES
COMPRESSION ATTACK TIME (2:1)
COMPRESSED
ATTACK
TIME
AMPLITUDE
and below for expansion). If the appropriate threshold
is exceeded by a larger or smaller ratio, the attack time
is increased or decreased appropriately. The change is
proportional to the change in ratio in dB. For example,
release time is reduced by 50% for 6dB.
For compression, if the signal amplitude exceeds the
threshold by 12dB, the attack time when entering com-
pression precisely matches the selected configuration.
Likewise, when exiting compression, the release time
is determined by the ratio by which the threshold was
exceeded prior to the amplitude dropping.
Expansion works in exactly the same fashion except for
two differences. The expansion ratio is applied when the
signal amplitude drops below the expansion threshold
(rather than above for compression), and the release time
(rather than attack time) determines how long it takes to
enter expansion (centered at 12dB below the expansion
threshold). Likewise, the attack time is then used when
exiting expansion. In addition, when entering expansion,
the ratio of the initial input amplitude to the expansion
threshold sets a delay before the expansion ratio is
applied. This delay is centered at 12dB above the expan-
sion threshold and is determined by the selected release
time. There is no delay prior to the attack time when exit-
ing expansion.
Ultra-Low Power Stereo Audio Codec
COMPRESSION RELEASE TIME (2:1)
RELEASED AMPLITUDE
COMPRESSED AMPLITUDE
AMPLITUDE
DECECREASES
RELEASE
TIME
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