The MAX5440 dual, 40kΩ logarithmic taper volume control
features a debounced up/down interface for use
with a simple rotary encoder without using a microcontroller
(μC). Each potentiometer has 32 log-spaced tap
points with a buffered wiper output and replaces
mechanical potentiometers. An integrated bias generator
provides the required ((VDD + VSS) / 2) bias voltage,
eliminating the need for costly external op-amp circuits
in unipolar audio applications. A mode-indicator LED
output specifies volume or balance control. Five integrated
LED drivers indicate volume level or balance settings,
depending on the status of the mode indicator.
The MAX5440 includes debounced pushbutton inputs
for mute and mode. The mute input allows a single
pushbutton to change between volume control and the
-90dB (typ) mute setting. The mode input toggles
between volume and balance control. A click-and-pop
suppression feature minimizes the audible noise generated
by wiper transitions. The MAX5440 provides a
nominal temperature coefficient of 35ppm/°C end-toend
and 5ppm/°C, ratiometrically. The MAX5440 is
available in a 24-pin SSOP package and is specified for
operation over the -40°C to +85°C extended temperature
range.
Applications
Stereo Volume Control
Desktop Speakers
Multimedia Docking Stations
Set-Top Boxes
Automotive Back-Seat Multimedia