MAXIM MAX5440 User Manual
General Description
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
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
MAX5440
Stereo Volume Control
with Rotary Encoder Interface
________________________________________________________________
Maxim Integrated Products
1
Pin Configuration
V
DD
V
SS
(V
DD + VSS
) / 2
(V
DD + VSS
) / 2
V
LOGIC
V
PEAK
H1
L1
W1
SHDN
LEFT INPUT
RIGHT INPUT
MODEIND
HEADPHONE
DRIVER
L0
H0
W0
V
LOGIC
LEDIND4
LEDIND3
LEDIND0
GND
MUTE
MODE
RENCODEA
RENCODEB
LEDIND1
LEDIND2
ROTARY
ENCODER
MIDBIAS
BIAS
MAX5440
Typical Operating Circuit
19-0542; Rev 2; 11/08
Ordering Information
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
PART TEMP RANGE PIN-PACKAGE
MAX5440EAG -40°C to +85°C 24 SSOP
TOP VIEW
V
LOGIC
RENCODEB
RENCODEA
2
3
MUTE
4
MODE
SHDN
GND
H0
L0
W0
MIDBIAS
BIAS
MAX5440
5
6
7
8
9
11
12
SSOP
1
24
23
22
21
20
19
18
17
16
1510W1
14
13
GND
MODEIND
LEDIND4
LEDIND3
LEDIND2
LEDIND1
LEDIND0
H1
L1
V
SS
V
DD
MAX5440
Stereo Volume Control
with Rotary Encoder Interface
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
SHDN, MUTE, RENCODEA, RENCODEB,
and MODE to GND............................-0.3V to (V
LOGIC
+ 0.3V)
H_, L_, and W_ to V
SS
...............................-0.3V to (VDD+ 0.3V)
LEDIND_, MODEIND to GND................-0.3V to (V
LOGIC
+ 0.3V)
MIDBIAS, BIAS to V
SS
......................(VSS- 0.3V) to (VDD+ 0.3V)
V
LOGIC
to GND...........................................-0.3V to (VDD+ 0.3V)
V
DD
to GND..............................................................-0.3V to +6V
V
DD
to VSS................................................................-0.3V to +6V
V
SS
to GND...............................................................-3V to +0.3V
Input and Output Latchup Immunity...............................±200mA
Continuous Power Dissipation (T
A
= +70°C)
24-Pin SSOP (derate 12.3mW/°C above +70°C) ......987.7mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VDD= +2.7V to +5.5V, VSS= V
GND
= 0, 2.7V ≤ (VDD- VSS) ≤ 5.5V, V
LOGIC
= +2.7V to VDD, V
H_
= VDD, V
L_
= VDD/ 2, TA= T
MIN
to
T
MAX
, unless otherwise specified. Typical values are at TA= +25°C.) (Note 1)
2 _______________________________________________________________________________________
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
End-to-End Resistance R 36 40 52 kΩ
Absolute Tolerance ±0.25 dB
Tap-to-Tap Tolerance ±0.1 dB
Total Harmonic Distortion Plus
Noise
Channel Isolation 100 dB
Interchannel Matching ±0.5 dB
Mute Attenuation SHDN = V
Power-Supply Rejection Ratio PSRR Input referred, 217Hz, 100mV
H Terminal Capacitance C
L Terminal Capacitance C
End-to-End Resistance
Ratiometric Resistance
Bandwidth, -3dB f
Output Noise e
WIPER BUFFER
Output Voltage Swing V
Output Current 3mA
Output Resistance R
DC Offset -14 ±2 +14 mV
INTEGRATED BIAS GENERATOR
Output Voltage I
V
= ( V
H _
= ∞ to V
V
= ( V
H _
= ∞ to V
R
L
V
= 5V,V
THD+N
DD
(VDD / 2) + 1V
10kΩ to V
= 5V,V
V
DD
2) + 1.5V
to V
MIDBIAS
H
L
CUTOFFCW
n
O
OWB
= 33pF 100 kHz
20Hz to 20kHz 3.2 µV
RL = 10kΩ to V
= 1mA
LOAD
/ 2) + 1V
D D
= V
L_
D D
/ 2) + 1.5V
D D
= V
L_
= 0V, V
SS
RMS
MIDBIAS
= 0V, V
SS
1kHz tap at top, RL = 10kΩ
RM S ,
, 20Hz to 20kHz
DD
MIDBIAS
, 1kH z tap at top , R
RM S
/ 2, 20H z to 20kH z
, 1kH z tap at top ,
RM S
/ 2, 20H z to 20kH z
D D
= 1.5V, V
L_
H_
, 1kHz tap at top, RL =
=
L
0.004
0.006
0.004
, 20Hz to 20kHz
= 5V, V
L_
H _
= ( V
D D
/
0.006
90 dB
P-P
on V
DD
-60 dB
5pF
7pF
35 ppm/°C
5 ppm/°C
VDD - 0.2 V
110Ω
(V
DD
) / 2
V
SS
- 30mV
(V
+
DD
V
/ 2
SS
( V
+
)
V
S S
+
D D
) / 2 +
30m V
%
RMS
V
MAX5440
Stereo Volume Control
with Rotary Encoder Interface
ELECTRICAL CHARACTERISTICS (continued)
(VDD= +2.7V to +5.5V, VSS= V
GND
= 0, 2.7V ≤ (VDD- VSS) ≤ 5.5V, V
LOGIC
= +2.7V to VDD, V
H_
= VDD, V
L_
= VDD/ 2, TA= T
MIN
to
T
MAX
, unless otherwise specified. Typical values are at TA= +25°C.) (Note 1)
Note 1: Parameters are 100% production tested at +85°C and limits through temperature are guaranteed by design.
Note 2: The device draws current in excess of the specified supply current when the digital inputs are driven with voltages between
(V
DD
- 0.5V) and (GND + 0.5V). See Digital Supply Current vs. Digital Input Voltage in the
Typical Operating Characteristics
.
Note 3: Shutdown refers to the SHDN input being asserted low. Standby refers to SHDN not being asserted and all I/O inactive.
Note 4: Supply current measured with the wiper position fixed.
_______________________________________________________________________________________ 3
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Power-Supply Rejection Ratio PSRR
Maximum Load To V
Output Resistance R
OBR
1kHz, 100mV on VDD, 1µF on BIAS 60 dB
BR
or GND 3 kΩ
DD
6 Ω
CONTACT INPUTS (MUTE, MODE, RENCODEA, RENCODEB)
Internal Pullup Resistor R
Single Pulse Input Low Time t
Repetitive Input Pulse Separation t
Timeout Period t
PULLUP
CPW
IPWS
WS
22 ms
66 ms
Click/pop suppression inactive 32 ms
45 kΩ
DIGITAL INPUTS (MUTE, MODE, RENCODEA, RENCODEB, SHDN)
Input High Voltage (Note 2) V
Input Low Voltage (Note 2) V
3.6V < V
IH
2.7V ≤ V
3.6V < V
IL
2.7V ≤ V
≤ 5.5V 2.4
LOGIC
≤ 3.6V 2.0
LOGIC
≤ 5.5V 0.8
LOGIC
≤ 3.6V 0.6
LOGIC
V
V
Input Leakage Current Inputs unconnected -1 +1 µA
Input Capacitance 5pF
POWER SUPPLIES
Supply Voltage V
DD
Negative Power Supply V
Supply Voltage Difference V
Active Supply Current I
S tand b y S up p l y C ur r ent ( N otes 3, 4) I
Shutdown Supply Current I
Power-Up Time t
Logic Supply Voltage V
DD
STBY
SHDN
PU
LOGICVSS
Logic Active Supply Current I
Logic Standby Supply Current I
Logic Shutdown Current I
LSTBY
LSHDN
VSS = 0 2.7 5.5 V
VDD = +2.7V -2.7 0 V
SS
- V
DD
SS
VDD = +5V, VSS = 0 1.3
VDD = +2.7V, VSS = -2.7V 1.3
(Note 3) 1 µA
Click/pop suppression inactive 50 ms
= 0 2.7 V
V
L
RENCODEA = VRENCODEB
= 0V 320 µA
(Note 4) 1 µA
5.5 V
1.4 mA
mA
DD
V
1µA
LED INDICATORS (LEDIND0–LEDIND4, MODEIND)
Output Low Voltage V
OL
LOGIC
V
LOGIC
= 2.7V, I
= 5.5V, I
= 10mA 0.4
SINK
= 10mA 0.2
SINK
V
V
Output Leakage Current 0.1 10 µA
Output Capacitance 3pF
Maximum Sink Current 150 mA
MAX5440
Stereo Volume Control
with Rotary Encoder Interface
4 _______________________________________________________________________________________
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
-70
-60
-40
-50
-20
-10
-30
0
08124 1620242832
ATTENUATION vs. TAP POSITION
MAX5440 toc01
TAP POSITION
ATTENUATION (dB)
-0.25
-0.15
-0.20
-0.05
-0.10
0.05
0
0.10
-40 10-15 35 60 85
END-TO-END RESISTANCE % CHANGE
vs. TEMPERATURE
MAX5440 toc02
TEMPERATURE (°C)
END-TO-END RESISTANCE CHANGE (%)
1.38
1.41
1.40
1.39
1.42
1.43
1.44
1.45
1.46
1.47
1.48
-40 10-15 35 60 85
TOTAL SUPPLY CURRENT
vs. TEMPERATURE
MAX5440 toc03
TEMPERATURE (°C)
TOTAL SUPPLY CURRENT (mA)
V
LOGIC
= VDD = 5.5V
WIPER
TRANSITION
FROM -2dB
TO -4dB
20ms/div
WIPER SWITCHING TRANSIENT
MAX5440 toc04
RENCODEA
RENCODEB
51ms
0
20
10
40
30
60
50
70
90
80
100
08124 1620242832
WIPER-TO-END TERMINAL VOLTAGE
vs. TAP POSITION
MAX5440 toc05
TAP POSITION
NOMINAL END-TO-END VOLTAGE (%V
HL
)
V
HW
V
WL
-2.8
-2.0
-2.4
-0.4
-0.8
-1.2
-1.6
0.8
0.4
0
0.01 10.1 10 100 1000
FREQUENCY RESPONSE
MAX5440 toc06
FREQUENCY (kHz)
RESPONSE (dB)
VH_ = 2.5 ±1V
RMS
, VL_ = 2.5V, CL_ = 33pF
W_ SET TO 0dB
-8.8
-8.0
-8.4
-6.4
-6.8
-7.6
-7.2
-5.6
-6.0
-5.2
0.01 10.1 10 100 1000
FREQUENCY RESPONSE
MAX5440 toc07
FREQUENCY (kHz)
RESPONSE (dB)
W_ SET TO -6dB
VH_ = 2.5 ±1V
RMS
, VL_ = 2.5V, CL_ = 33pF
0.001
0.01
0.1
0.001 0.10.01 1 10 100
THD+N vs. FREQUENCY
MAX5440 toc08
FREQUENCY (kHz)
W_ SET AT -2dB
THD+N (%)
VDD = 2.5V
V
SS
= -2.5V
L_ = V
MIDBIAS
H_ = V
MIDBIAS
+ 1V
RMS
W_ SET AT -6dB
W_ SET AT 0dB
0.001
0.01
0.1
0.001 0.10.01 1 10 100
THD+N vs. FREQUENCY
MAX5440 toc09
FREQUENCY (kHz)
THD+N (%)
VDD = 5.0V
V
SS
= GND
L_ = V
MIDBIAS
H_ = V
MIDBIAS
+ 1V
RMS
W_ SET AT -2dB
W_ SET AT -6dB
W_ SET AT 0dB
MAX5440
Stereo Volume Control
with Rotary Encoder Interface
-75
-65
-70
-45
-50
-55
-60
-35
-40
-25
-30
0.01 10.1 10 100
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX5440 toc10
FREQUENCY (kHz)
RESPONSE (dB)
V
DD_
= 5V ±100mV
P-P
, VH = 5V
V
L_
= 2.5V, W_ SET TO -6dB
0
100
50
200
150
250
300
LOGIC SUPPLY CURRENT
vs. LOGIC SUPPLY VOLTAGE
MAX5440 toc11
LOGIC SUPPLY VOLTAGE (V)
LOGIC SUPPLY CURRENT (µA)
2.5 3.5 4.03.0 4.5 5.0 5.5
ACTIVE CURRENT
STANDBY CURRENT
SHUTDOWN
0
100
50
200
150
300
250
350
-40 10-15 35 60 85
ACTIVE LOGIC SUPPLY CURRENT
vs. TEMPERATURE
MAX5440 toc12
TEMPERATURE (°C)
LOGIC SUPPLY CURRENT (µA)
VDD = V
LOGIC
= 5.5V,
RENCODEA = RENCODEB = 0
1.1752
1.1756
1.1754
1.1762
1.1760
1.1758
1.1768
1.1766
1.1764
1.1770
-40 10-15 356085
ACTIVE SUPPLY CURRENT
vs. TEMPERATURE
MAX5440 toc13
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
VDD = V
LOGIC
= 5.5V,
RENCODEA = RENCODEB = 0
10
100
1000
0 0.5 2.0 2.51.0 1.5 3.0 3.5 4.0 4.5 5.0
DIGITAL SUPPLY CURRENT
vs. DIGITAL INPUT VOLTAGE
MAX5440 toc14
DIGITAL INPUT VOLTAGE (V)
DIGITAL SUPPLY CURRENT (µA)
200
0
400
800
600
1000
1200
0.01 10.1 10 100
SPECTRAL NOISE DENSITY
MAX5440 toc15
FREQUENCY (kHz)
NOISE (nV/√Hz)
0
1
2
3
4
5
6
7
8
2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY CURRENT
vs. INPUT VOLTAGE SWEEP
MAX5440 toc16
INPUT VOLTAGE SWEEP (VH_)
SUPPLY CURRENT (mA)
VDD = V
LOGIC
= 5V, W_ AT 0dB
R
L
= 10kΩ TO V
MIDBIAS
Typical Operating Characteristics (continued)
(V
DD
= +5V, TA = +25°C, unless otherwise noted.)
_______________________________________________________________________________________ 5
Loading...