Datasheet

Maxim Integrated │ 146
MAX98090 Ultra-Low Power Stereo Audio Codec
www.maximintegrated.com
Volume smoothing is available on all analog output PGAs.
When enabled, all volume changes are broken into the
smallest available step size. The volume is then ramped
through each step between the initial and final volume set-
ting at a rate of one step every 1ms. Volume smoothing
also occurs at device turn-on and turn-off. During turn-on,
the volume is first set to mute before the output is enabled.
Once enabled, mute is first disabled and then the volume
is ramped to the programmed level. At turn-off, the volume
is ramped down to the minimum gain, and then muted,
before the outputs are disabled. If zero-crossing detection
is enabled, each volume step occurs at a zero crossing.
When no audio signal is present, zero-crossing detection
can timeout and prevent volume smoothing from occurring.
Enable enhanced volume smoothing to prevent the
volume controller from requesting another volume step
until the previous step has been set. Each step in the
volume ramp then occurs either after a zero crossing has
occurred in the audio signal or after the timeout window
has expired.
During PGA turn-off, volume smoothing ramps the volume
down to the minimum setting, if enabled. However, to
prevent long turn off times enhanced volume smoothing
and zero-crossing detection is not applied at PGA mute
or turn-off. If volume smoothing is too slow or is not used,
the zero-crossing detection can still be used to minimize
click and pop when disabling an output PGA. First ramp
the PGA volume down to (in one step or multiple steps)
its minimum volume setting. Zero-crossing detection is
applied to each step of the volume change. Then, once
at the minimum volume, either enable mute or disable the
output PGA.
Table 75. Zero-Crossing Detection and Volume Smoothing Configuration Register
ADDRESS: 0x40
DESCRIPTION
BIT NAME TYPE POR
7 — — — —
6 — — — —
5 — — — —
4 — — — —
3 — — — —
2 ZDEN R/W 0
Zero-Crossing Detection
0: Volume changes made only at zero crossings or after approximately 100ms.
1: Volume changes made immediately upon request.
1 VS2EN R/W 0
Enhanced Volume Smoothing
Only valid is volume adjustment smoothing is enabled (VSEN = 0).
0: Each volume change waits until the previous volume step has been applied to the
output. Allows volume smoothing to function with zero-crossing timeout.
1: Volume smoothing enhancement is disabled.
0 VSEN R/W 0
Volume Adjustment Smoothing
0: Volume changes are smoothed by stepping through intermediate levels.
1: Volume changes are made directly in a single step.