MAX5440_08 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – Stereo Volume Control with Rotary Encoder Interface

19-0542; Rev 2; 11/08
Stereo Volume Control
with Rotary Encoder Interface
General Description
The MAX5440 dual, 40kΩ logarithmic taper volume con-
trol features a debounced up/down interface for use
with a simple rotary encoder without using a microcon-
troller (µC). Each potentiometer has 32 log-spaced tap
points with a buffered wiper output and replaces
mechanical potentiometers. An integrated bias genera-
tor provides the required ((V_DD + V_SS) / 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 inte-
grated LED drivers indicate volume level or balance set-
tings, 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 gener-
ated by wiper transitions. The MAX5440 provides a
nominal temperature coefficient of 35ppm/°C end-to-
end 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 tempera-
ture range.
Applications
Stereo Volume Control
Desktop Speakers
Multimedia Docking Stations
Set-Top Boxes
Automotive Back-Seat Multimedia
Pin Configuration
TOP VIEW
V_LOGIC 1
RENCODEB 2
RENCODEA 3
MUTE 4
MODE 5
SHDN 6
GND 7
H0 8
L0 9
W0 10
MIDBIAS 11
BIAS 12
MAX5440
SSOP
24 GND
23 MODEIND
22 LEDIND4
21 LEDIND3
20 LEDIND2
19 LEDIND1
18 LEDIND0
17 H1
16 L1
15 W1
14 V_SS
13 V_DD
Features
♦ Logarithmic Taper Volume Control with (31) 2dB
Steps
♦ Low-Power Wiper Buffers Provide 0.003% THD
♦ Single +2.7V to +5.5V or Dual ±2.7V Supply
Voltage Operation
♦ Low 0.5µA Shutdown Supply Current
♦ Integrated Bias Voltage Generator
♦ Five-Segment LED Volume/Balance Indicator
♦ Clickless Switching
♦ 40kΩ End-to-End Fixed Resistance Value
♦ Mute Function Toggles to -90dB (typ)
♦ Power-On Reset to -12dBFS Wiper Position
PART
MAX5440EAG
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
24 SSOP
Typical Operating Circuit
VDD
VLOGIC
VLOGIC
SHDN
MAX5440
(VDD + VSS) / 2
LEDIND0
LEDIND1
LEDIND2
LEDIND3
LEDIND4
VSS
MODEIND
VPEAK
(VDD + VSS) / 2
H1
W1
RIGHT INPUT
L1
MIDBIAS
HEADPHONE
DRIVER
L0
LEFT INPUT
W0
H0
BIAS
ROTARY
ENCODER
________________________________________________________________ Maxim Integrated Products 1
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