Rainbow Electronics MAX5440 - Manual (Page 9)

Balance Control
In balance-control mode, the MAX5440 adjusts the bal-
ance between channel 0 and channel 1 while maintain-
ing the set volume. For example, if the volume of
channel 0 equals the volume of channel 1, forcing the
balance towards channel 1 increases the attenuation of
channel 0 (
Figure 3a). If channel 1 is at a higher attenu-
ation than channel 0, adjusting the balance to channel
1 moves channel 1’s wiper up to the same wiper posi-
tion as channel 0 before it was attenuated (Figure 3b).
Click-and-Pop Suppression
The click-and-pop suppression feature reduces the
audible noise (clicks and pops) that results from wiper
transitions. The MAX5440 minimizes this noise by allow-
ing the wiper to change position only when V
H = V L .
Each wiper has its own suppression and timeout cir-
cuitry. The MAX5440 changes wiper position when V
H
= V L , or after 32ms, whichever occurs first (see Figures
4a and 4b).
The suppression circuitry monitors left and right chan-
nels separately. In volume-control mode, when the first
wiper changes position, the second wiper has 32ms to
change or it will be forced to change.
MAX5440
Stereo Volume Control
with Rotary Encoder Interface
Table 1. Wiper Position and Attenuation
POSITION ATTENUATION (dB)
0 0
1 -2
2 -4
… …
6 (POR) -12
… …
30 -60
31 -62
32 (MUTE) ≥ 90
_______________________________________________________________________________________ 9
W0 W1 W0 W1 W0 W1
H_
L_
W0 W1 W0 W1 W0 W1
H_
L_
ROTATE CW
ONCE
ROTATE CW
ONCE
ROTATE CW
ONCE
ROTATE CW
ONCE
VOLUME LEVEL IS SET
VOLUME LEVEL IS SET BY W0
VOLUME LEVEL MAINTAINED
BALANCE SHIFTS TO W1
VOLUME LEVEL MAINTAINED
BALANCE SHIFTS TO W1
Figure 3. Balance-Control Operation