MAX5457 Maxim Integrated Products, MAX5457 Datasheet - Page 10

• Manufacturer Part Number: MAX5457
• Description: Stereo Audio Taper Potentiometers
• Manufacturer: Maxim Integrated Products

Stereo Audio Taper Potentiometers
with Pushbutton Interface
The click/pop suppression feature reduces the audible
noise (clicks and pops) that result from wiper transitions.
The MAX5456/MAX5457 minimize this noise by allowing
the wiper position changes only when V
the wiper changes position only when the voltage at L_ is
the same as the voltage at the corresponding H_. Each
wiper has its own suppression and timeout circuitry (see
Figure 5a). The MAX5456/MAX5457 change wiper posi-
tion after 32ms or when V
(see Figure 5b).
Figure 5a. Wiper Transition Timing Diagram
10
______________________________________________________________________________________
DN OR UP
USER PRESSES PUSHBUTTON
H_
Click/Pop Suppression
WIPER MOTION
= V
1
0
L
, whichever occurs first
V
V
H
L
IS BOUNCING
CONTACT
SWITCH
H_
= V
STABLE LOW, t
DEBOUNCE BY
WAITING FOR
L_
IS STABLE
CONTACT
SWITCH
. Thus,
t
IPW
IPW
CROSSING, t
FIRST ZERO
WAIT FOR
INPUT ACCEPTED
t
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.
The power-on comparators monitor V
V
of the supplies is brought back to normal operating
voltage. The power-on-reset feature sets both wipers to
-12dB. Power-on reset places the MAX5457 in volume-
control mode.
WS
LOGIC
WIPER MOVES HERE
WS
- GND. A power-on reset is initiated when either
2dB
STEPS
IS BOUNCING
CONTACT
SWITCH
STABLE HIGH, t
DEBOUNCE BY
WAITING FOR
t
HPW
HPW
READY TO ACCEPT
ANOTHER KEYPRESS
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Power-On Reset
DD
- V
SS
and