General Description
The MAX5456/MAX5457 dual, logarithmic taper digital
potentiometers feature a simple pushbutton interface
that controls volume and balance in audio applications.
Each potentiometer has 32 tap points and replaces
mechanical potentiometers. Refer to the MAX5408–
MAX5411 data sheet for SPI™ versions of the MAX5456/
MAX5457.
Use the MAX5456/MAX5457 digital inputs with momentary contact single-pole/single-throw (SPST) pushbutton
switches. Each input includes internal debounce circuitry and a 50kΩ pullup resistor.
The MAX5456/MAX5457 advance the wiper setting once
per button push. Maxim’s proprietary SmartWiper™ control eliminates the need for a microcomputer to increase
the wiper transition rate. Holding the control input low for
more than 1s advances the wiper at a rate of 4Hz for 4s
and 16Hz per second thereafter.
The MAX5456/MAX5457 provide temperature coefficients of 50ppm/°C end-to-end and 5ppm/°C ratiometric and a nominal resistance of 10kΩ per potentiometer.
An integrated click/pop suppression feature minimizes
the audible noise generated by wiper transitions. The
typical total harmonic distortion plus noise (THD+N) for
these devices is 0.01%.
The MAX5457 features a 3-button interface with a
MODE input that toggles between volume- and balancecontrol modes. An LED output indicates volume or balance mode. The MAX5456 features a 4-button interface
with separate inputs for up and down volume controls
and left and right balance controls.
The MAX5456/MAX5457 are available in 16-pin QSOP
and 16-pin TQFN packages and are specified over the
extended (-40°C to +85°C) temperature range.
Applications
Stereo Volume Control
Fading and Balancing Stereo Signals
Stereo Blending and Mixing
Features
♦ SmartWiper Control Provides Accelerated Wiper
Motion
♦ Debounced Pushbutton Interface with Internal
Pullup Resistors
♦ Logarithmic Taper with 2dB Steps Between Taps
♦ Single +2.7V to +5.5V or Dual ±2.7V Supply
Operation
♦ Low 0.5µA Standby Supply Current
♦ Clickless Switching
♦ 10kΩ End-to-End Fixed Resistance Value
♦ Mute Function to -90dB (typ)
♦ Power-On Reset to -12dB Wiper Position
♦ 32 Tap Positions for Each Wiper
♦ Small 16-Pin QSOP/TQFN Packages
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3490; Rev 1; 12/05
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Typical Application Circuits and Selector Guide appear at
end of data sheet.
SPI is a trademark of Motorola, Inc.
SmartWiper is a trademark of Maxim Integrated Products, Inc.
TOP VIEW
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
DN/BAL0
V
DD
V
LOGIC
GND
V
SS
H1
L1
W1
MUTE
MAX5457
QSOP
UP/BAL1
MODE
L0
MODE_IND
H0
W0
SHDN
Pin Configurations
Pin Configurations are continued at end of data sheet.
*Future product—contact factory for availability.
PART TEMP RANGE
o
MAX5456EEE -40
MAX5456ETE* -40oC to +85oC 16 TQFN T1644-4
MAX5457EEE -40oC to +85oC 16 QSOP E16-1
MAX5457ETE* -40oC to +85oC 16 TQFN T1644-4
C to +85oC 16 QSOP E16-1
PINPACKAGE
PKG
CODE
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDD= V
LOGIC
= +2.7V to +5.5V, VSS= 0V, GND = 0V, V
H_
= VDD, V
L_
= VSS, TA= T
MIN
to T
MAX
. Typical values are at TA= +25°C,
unless otherwise specified.) (Note 1)
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.
(MAX5456) SHDN, MUTE, VOLUP, VOLDN,
BAL_ to GND.....................................-0.3V to (V
LOGIC
+ 0.3V)
(MAX5457) SHDN, MUTE, UP/BAL1, DN/BAL0, MODE,
MODE_IND to GND...........................-0.3V to (V
LOGIC
+ 0.3V)
H_, L_, and W_ to V
SS
..............................-0.3V to (VDD+ 0.3 V)
V
DD
to GND..............................................................-0.3V to +6V
V
DD
to VSS................................................................-0.3V to +6V
V
LOGIC
to GND.........................................................-0.3V to +6V
V
LOGIC
to VSS...........................................................-0.3V to +6V
V
SS
to GND............................................................-3.0V to +0.3V
Peak Current into H_, L_, and W_.......................................±1mA
Average Current into H_, L_, and W_ ..............................±500µA
Input and Output Latchup Immunity...............................±200mA
Continuous Power Dissipation (T
A
= +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)........666.7mW
16-Pin TQFN (derate 16.9mW/°C above +70°C) ....1349.1mW
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
End-to-End Resistance R Figures 1, 2 7 10 13 kΩ
Maximum Bandwidth f
Absolute Ratio Tolerance N o l oad at the outp ut of the w i p er , W _ = - 6d B ±0.25 dB
Tap-to-Tap Tolerance ±0.1 dB
Total Harmonic Distortion Plus
Noise
Channel-to-Channel Isolation -100 dB
Interchannel Matching f = 20Hz to 20kHz, tap = -6dB ±0.5 dB
Mute Attenuation -90 dB
Power-Supply Rejection Ratio PSRR -80 dB
Wiper Resistance R
Wiper Capacitance C
H Terminal Capacitance C
L Terminal Capacitance C
End-to-End Resistance
Temperature Coefficient
Ratiometric Resistance
Temperature Coefficient
Output Noise e
PUSHBUTTON CONTACT INPUTS (UP/BAL1, DN/BAL0, MUTE, VOLUP, VOLDN, BAL0, BAL1, MODE)
Internal Pullup Resistor R
Single Pulse-Width Input t
Repetitive Input Pulse High Time t
Timeout Period t
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CUTOFF
From H_ to W_, C
V
= 5V, VH_ = (V
DD
f = 1kHz, tap = -6dB, V
THD+N
V
= 3V, V
DD
V
= 1.5V + 1V
H_
(VDD / 2), CL = 5pF, tap = -6dB
W
W
H
L
n
PULLUP
lPW
HPW
WS
20Hz to 20kHz 0.95 µV
Figure 5 22.5 ms
Figure 5 40 ms
Click/pop suppression inactive 32 ms
SS
= 10pF 100 kHz
LOAD
/ 2) + 1V
DD
L_
= 0V, V
L_
, f = 1kHz, RL = 10kΩ to
RMS
= V
DD
= 1.5V,
RMS
,
/ 2, RL = ∞
0.01
0.23
1000 1700 Ω
10 pF
5pF
7pF
50 ppm/°C
5 ppm/°C
32 50 65 kΩ
%
RMS
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
_______________________________________________________________________________________ 3
Note 1: Parameters are 100% production tested at +85°C and limits through temperature are guaranteed by design.
Note 2: Supply current measured with the supply on and a button pushed.
Note 3: Supply current measured with the power on, no button pushed, and the wiper position fixed.
Note 4: This is the measured current with SHDN low and MODE_IND unconnected.
ELECTRICAL CHARACTERISTICS (continued)
(VDD= V
LOGIC
= +2.7V to +5.5V, VSS= 0V, GND = 0V, V
H_
= VDD, V
L_
= VSS, TA= T
MIN
to T
MAX
. Typical values are at TA= +25°C,
unless otherwise specified.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
First Autoincrement Point 1 s
First Autoincrement Rate 4Hz
Second Autoincrement Point 4s
Second Autoincrement Rate 16 Hz
DIGITAL INPUTS (V
Input High Voltage V
Input Low Voltage V
LOGIC
> 4.5V)
IH
IL
2.4 V
0.8 V
Input Leakage Current Inputs floating ±1 µA
Input Capacitance 5pF
DIGITAL INPUTS (V
Input High Voltage V
Input Low Voltage V
LOGIC
< 4.5V)
IH
IL
0.7 x
V
L OGIC
0.3 x
V
L OGIC
V
V
Input Leakage Current Inputs floating ±1 µA
Input Capacitance 5pF
POWER SUPPLIES
Supply Voltage V
Negative Power Supply V
DD
SS
Supply-Voltage Difference VDD - V
Active Supply Current I
Standby Supply Current I
Shutdown Supply Current I
Power-Up Time t
Logic Standby Voltage V
Logic Active Supply Current I
Logic Standby Supply Current I
Logic Shutdown Current I
LOGICSTBY
LOGICSHDN
DD
STBY
SHDN
PU
LOGIC
LOGIC
(Note 2) 100 µA
V
= + 5.5V , V
D D
V
LOGIC
(Note 4) 1 µA
(Note 2) 160 µA
(Note 3) 0.5 1 µA
(Note 4) 1 µA
SS
= 0V , V
S S
= 2.7V ( N ote 3) 2 10
LOGIC
= VDD = +2.7V, VSS = -2.7V (Note 3) 0.5 1
2.7 5.5 V
-2.7 0 V
5.5 V
10 ms
2.7 V
DD
µA
V
DIGITAL OUTPUT, MODE_IND
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
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VDD= V
LOGIC
= +2.7V to +5.5V, VSS= 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA= T
MIN
to T
MAX
. Typical values are at TA= +25°C,
unless otherwise specified.)
WIPER RESISTANCE vs. WIPER VOLTAGE
MAX5456/7 toc01
WIPER VOLTAGE (V)
WIPER RESISTANCE (Ω)
4.53.5 4.01.5 2.0 2.5 3.01.0
650
700
750
800
850
900
950
1000
1050
1100
1150
1200
600
0.5 5.0
VDD = V
LOGIC
= 5V
ATTENUATION vs. TAP POSITION
MAX5456/7 toc02
TAP POSITION
ATTENUATION (dB)
282420161284
-60
-50
-40
-30
-20
-10
0
-70
032
END-TO-END RESISTANCE % CHANGE
vs. TEMPERATURE
MAX5456/7 tpc03
TEMPERATURE (°C)
END-TO-END RESISTANCE CHANGE (%)
603510-15
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
-0.5
-40 85
ACTIVE SUPPLY CURRENT vs. TEMPERATURE
ACTIVE SUPPLY CURRENT (µA)
185
190
195
200
210
205
215
220
180
MAX5456/7 toc04
TEMPERATURE (°C)
603510-15-40 85
VDD = V
LOGIC
= 5.5V,
I
LOGIC
+ I
VDD
WIPER SWITCHING TRANSIENT
(TIMING OUT)
MAX5456/7 toc05a
10ms/div
5V/div
1V/div
VOLUP
WIPER TRANSITION
FROM -2dB to 0dB
VH_ = V
DD
VL_ = 0
WIPER SWITCHING TRANSIENT
(SUPPRESSION CIRCUIT ACTIVE)
MAX5456/7 toc05b
4ms/div
5V/div
2V/div
VOLUP
WIPER TRANSITION
FROM -2dB to 0dB
VH_ = SQUARE WAVE FROM
V
DD
TO VSS, VL_ = V
DD
/ 2
LOGIC SUPPLY CURRENT
vs. LOGIC SUPPLY VOLTAGE
MAX5456/7 toc06a
LOGIC SUPPLY VOLTAGE (V)
LOGIC SUPPLY CURRENT (µA)
20
40
60
80
100
120
140
160
180
200
0
ACTIVE LOGIC SUPPLY
CURRENT
5.2 5.54.2 4.73.73.22.7
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(VDD= V
LOGIC
= +2.7V to +5.5V, VSS= 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA= T
MIN
to T
MAX
. Typical values are at TA= +25°C,
unless otherwise specified.)
0.05
0.10
0.15
0.20
0.25
0.30
0
LOGIC SUPPLY CURRENT
vs. LOGIC SUPPLY VOLTAGE
MAX5456/7 toc06b
LOGIC SUPPLY VOLTAGE (V)
LOGIC SUPPLY CURRENT (µA)
5.2 5.54.2 4.73.73.22.7
STANDBY LOGIC SUPPLY
CURRENT
WIPER-TO-END TERMINAL RESISTANCE
vs. TAP POSITION
MAX5456/7 toc07
TAP POSITION
NOMINAL END-TO-END RESISTANCE (%R
HL
)
24168
25
50
75
100
0
032
R
WH
R
WL
SPECTRAL NOISE DENSITY
MAX5456 toc13
FREQUENCY (kHz)
NOISE (nV
RMS
/√
Hz
)
1010.1
1
2
3
4
5
6
7
8
9
10
0
0.01 100
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
VH_ = 2.5V ±1V
W_ SET TO -6dB,
10
20Hz TO 20kHz BANDPASS
1
0.1
THD+N (%)
0.01
0.001
0.0001
10 100,000
, VL_ = 2.5V,
P-P
LOAD = 10kΩ
NO LOAD
FREQUENCY (Hz)
DIGITAL SUPPLY CURRENT
vs. DIGITAL INPUT VOLTAGE
1000
900
800
MAX5456/7 toc09
700
600
500
400
300
DIGITAL SUPPLY CURRENT (µA)
200
100
0
10,0001000100
05
DIGITAL INPUT VOLTAGE (V)
4321
FREQUENCY RESPONSE
VH_ = 2.5V ±1V
2
= 10pF
C
L_
0
-2
RESPONSE (dB)
-4
-6
-8
0.01 1000
, VL_ = 2.5V,
P-P
W_ SET TO 0dB
W_ SET TO -6dB
FREQUENCY (kHz)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
0
MAX5456/7 toc10
VDD = 5V ±1V
-10
-20
-30
-40
-50
PSRR (dB)
-60
-70
-80
-90
= 2.5V, W_ SET TO -6dB
V
L_
11000
, VH_ = 5V,
P-P
FREQUENCY (kHz)
MAX5456/7 toc08
1001010.1
MAX5456/7 toc11
10010
LOGIC SUPPLY CURRENT
vs. TEMPERATURE
150
149
V
= 5.5V
LOGIC
148
147
ACTIVE LOGIC SUPPLY
146
CURRENT
145
144
143
LOGIC SUPPLY CURRENT (mA)
142
141
140
-40 85
TEMPERATURE (°C)
MAX5456/7 toc12
603510-15
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
6 _______________________________________________________________________________________
Pin Description
PIN
MAX5457 MAX5456
TQFN
NAME FUNCTION
13——MODE
Volume/Balance Control. Each transition from high to low toggles between volume
and balance modes. MODE is pulled high internally with a 50kΩ resistor to V
LOGIC
.
On power-up, the MAX5457 is in volume-control mode.
24——
Volume-Control/Balance-Control Mode Indicator Open-Drain Output. Connect to
an LED through a resistor to V
LOGIC
. When the LED is on, the MAX5457 is in
balance-control mode. When the LED is off, the MAX5457 is in volume-control
mode. See the Mode Indicator, MODE_IND section for more detail.
3 535 H0 Potentiometer 0 High Terminal. H0 and L0 terminals can be reversed.
4 646 L0 Potentiometer 0 Low Terminal. L0 and H0 terminals can be reversed.
5 757 W0 Potentiometer 0 Wiper Terminal
6 868SHDN
Active-Low Shutdown Input. In shutdown mode, the MAX5456/MAX5457 store the
last wiper settings. The wipers move to the L end of the resistor string, and the H
end of the resistor string disconnects from the signal input. Terminating shutdown
mode restores the wipers to their previous settings.
7 979 MUTE
Mute Input. When MUTE is low, the wiper goes to the highest attenuation setting
(see Table 1). MUTE is internally pulled up with 50kΩ to V
LOGIC
.
810810 W1 Potentiometer 1 Wiper Terminal
911911 L1 Potentiometer 1 Low Terminal. L1 and H1 terminals can be reversed.
10 12 10 12 H1 Potentiometer 1 High Terminal. H1 and L1 terminals can be reversed.
11 13 11 13 V
SS
Negative Power Supply. Bypass with 0.1µF to ground.
12 14 12 14 GND Ground
13 15 13 15 V
LOGIC
Digital Logic Power Supply. Bypass with 0.1µF to ground.
14 16 14 16 V
DD
Analog Power Supply. Bypass with 0.1µF to ground.
15 1 — —
Downward Volume/Channel 0 Balance-Control Input. In volume mode, pressing
DN/BAL0 moves both wipers towards the L terminals. In balance mode, pressing
DN/BAL0 moves the balance towards channel 0. DN/BAL0 is internally pulled up
with 50kΩ to V
LOGIC
.
16 2 — —
Upward Volume/Channel 1 Balance-Control Input. In volume mode, pressing
UP/BAL1 moves both wipers towards the H terminals. In balance mode, pressing
UP/BAL1 moves the balance towards channel 1. UP/BAL1 is internally pulled up
with 50kΩ to V
LOGIC
.
—— 1 3 BAL1
Channel 1 Balance-Control Input. Pressing BAL1 moves the balance towards
channel 1. BAL1 is internally pulled up with 50kΩ to V
LOGIC
.
—— 2 4 BAL0
Channel 0 Balance-Control Input. Pressing BAL0 moves the balance towards
channel 0. BAL0 is internally pulled up with 50kΩ to V
LOGIC
.
——15 1 VOLDN
Downward Volume-Control Input. Pressing VOLDN moves both wipers towards
the L terminals. VOLDN is internally pulled up with 50kΩ to V
LOGIC
.
——16 2 VOLUP
Upward Volume-Control Input. Pressing VOLUP moves both wipers towards the
H terminals. VOLUP is internally pulled up with 50kΩ to V
LOGIC
.
QSOP TQFN QSOP
MODE_IND
DN/BAL0
UP/BAL1
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
_______________________________________________________________________________________ 7
Detailed Description
The MAX5456/MAX5457 dual, logarithmic taper digital
potentiometers feature a simple pushbutton interface that
controls volume and balance in audio applications. Each
potentiometer has 32 tap points and replaces mechanical
potentiometers (see the Functional Diagrams).
Up and Down Interface
The MAX5456/MAX5457 interface with momentary contact SPST switches. All switch inputs are internally
debounced and pulled up to V
LOGIC
through 50kΩ
resistors. The wiper setting advances once per button
press up to 1s. Maxim’s SmartWiper control circuitry
allows the wiper to advance at a rate of 4Hz when an
input is held low from 1s up to 4s, and at a rate of 16Hz
if the contact is maintained for greater than 4s (see
Table 2). The SmartWiper control eliminates the need for
a microcomputer to increase the wiper transition rate.
The MAX5456 features independent control inputs for
volume and balance control while the MAX5457 MODE
input toggles between volume and balance control.
Each transition of MODE from high to low toggles the
MAX5457 between volume-control and balance-control
modes. MODE is internally pulled high with a 50kΩ
resistor to V
LOGIC.
Volume Control
In volume-control mode, the MAX5456/MAX5457s’
wipers move simultaneously, maintaining the balance
separation between each wiper (Figure 3a).
When either wiper reaches the maximum tap position
(position closest to H_), further commands to increase
the volume are ignored. Balance separation is maintained in the maximum volume configuration (Figure 3b).
When either wiper reaches the minimum tap position
(position closest to L_), further commands to decrease
the volume adjust the other wiper until it also reaches
the minimum tap position (Figure 3c).
Increasing the volume from this minimum position
restores the original balance separation of the wipers
(Figure 3d).
When both wipers are in the 31st tap position (-62dB
attenuation), further commands to VOLDN place the
wipers in the mute position (see Table 1). VOLUP or
MUTE pulses return wipers to position 31.
Figure 1. Potentiometer Model (Active)
Figure 2. Potentiometer Model (Shutdown)
MAX5456
MAX5457
R
W_
W_
W
C
W
MAX5456
MAX5457
R
W
C
W
R
R
H_
C
H
L_
C
L
H_
C
H
L_
C
L
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
8 _______________________________________________________________________________________
Figure 3. Volume-Control Operation
Table 1. Wiper Position and Attenuation
H_
W0
(a)
L_
W0 W1
H_
(b)
W1
PRESS VOLUP
TWICE
PRESS VOLUP
ONCE
W0
W0
PRESS VOLDN
ONCE
PRESS VOLUP
BALANCE SEPARATION
MAINTAINED
W0W1 W1
NO CHANGE
W0W1 W1
FROM 3c
L_
H_
W0 W1
(c)
L_
H_
W0 W1
(d)
L_
POSITION ATTENUATION (dB)
00
12
24
…
…
PRESS VOLDN
ONCE
PRESS VOLUP
ONCE
W0
W0
PRESS VOLDN
PRESS VOLUP
ONCE
W0W1 W1
ORIGINAL BALANCE SEPARATION
MAINTAINED
W0W1 W1
TO 3d
6 (POR) 12
…
…
30 60
31 62
32 (mute) >90
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
_______________________________________________________________________________________ 9
Balance Control
In balance-control mode, the MAX5456/MAX5457
adjust the balance between channel 0 and channel 1
while maintaining 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 4a). If channel 1 is at a
higher attenuation than channel 0, adjusting the balance to channel 1 moves channel 1’s wiper up to the
same wiper position as channel 0 before attenuating
channel 0 (Figure 4b).
To control the wiper quickly with a logic signal, maintain pulses at least 22.5ms wide and separated by at
least 40ms.
Table 2. Wiper Action vs. Pushbutton
Contact Duration
Figure 4. Balance-Control Operation
H_
(a)
VOLUME LEVEL IS SET
W0
W1
PRESS BAL1
ONCE
CONTACT DURATION WIPER ACTION
t < 22.5ms No motion (debouncing).
22.5ms < t ≤ 1s Wiper changes position once.
Wiper changes position
at a rate of 4Hz.
Wiper changes position
at a rate of 16Hz.
VOLUME LEVEL MAINTAINED
BALANCE SHIFTS TO W1
W0W1 W1
W0
1s < t ≤ 4s
t > 4s
PRESS BAL1
ONCE
L_
H_
W0 W1
(b)
L_
PRESS BAL1
ONCE
W0
PRESS BAL1
ONCE
VOLUME LEVEL MAINTAINED
BALANCE SHIFTS TO W1VOLUME LEVEL IS SET BY W0
W0W1 W1
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
10 ______________________________________________________________________________________
Click/Pop Suppression
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
H_
= VL_. Thus,
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 position after 32ms or when VH_= VL, whichever occurs first
(see Figure 5b).
The suppression circuitry monitors left and right channels 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.
Power-On Reset
The power-on comparators monitor VDD- VSSand
V
LOGIC
- GND. A power-on reset is initiated when either
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 volumecontrol mode.
Figure 5a. Wiper Transition Timing Diagram
SWITCH
USER PRESSES PUSHBUTTON
1
DN OR UP
0
CONTACT
IS BOUNCING
STABLE LOW, t
SWITCH
CONTACT
IS STABLE
t
IPW
DEBOUNCE BY
WAITING FOR
SWITCH
WAIT FOR
FIRST ZERO
CROSSING, t
IPW
INPUT ACCEPTED
t
WS
WS
CONTACT
IS BOUNCING
DEBOUNCE BY
STABLE HIGH, t
t
HPW
WAITING FOR
READY TO ACCEPT
ANOTHER KEYPRESS
HPW
V
H
V
L
WIPER MOVES HERE
WIPER MOTION
2dB
STEPS
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
______________________________________________________________________________________ 11
Figure 5b. Wiper Transition Timing Diagram
Shutdown,
SHDN
Upon entering shutdown mode, the MAX5456/MAX5457
store the last wiper settings. The wipers move to the L_
end of the resistor string, and the H_ end of the resistor
string disconnects from the signal input. Terminating
shutdown mode restores the wipers to their previous
settings (see Figure 2). Shutdown does not affect the
state of MODE_IND.
Mute Function,
MUTE
The MAX5456/MAX5457 feature a mute function. Successive pulses on MUTE toggle its setting. Activating the mute
function forces both wipers to maximum attenuation (90dB typ). Deactivating the mute function returns the
wipers to their previous settings. Pressing VOLUP also
deactivates mute, setting the wipers to their previous
positions. MUTE is internally pulled high with a 50kΩ
resistor to VLOGIC. When both wipers are in the 31st
tap position (-62dB attenuation), further commands to
VOLDN place the wipers in the mute position (see
Table 1). VOLUP or MUTE pulses return the wipers to
position 31.
SWITCH
CONTACT
IS BOUNCING
1
0
SWITCH
CONTACT
IS STABLE
t
IPW
DEBOUNCE BY
WAITING FOR
STABLE LOW,
t
IPW
INPUT ACCEPTED
t
WAIT FOR
FIRST ZERO
CROSSING OR
TIMEOUT, t
SWITCH
CONTACT
IS BOUNCING
t
HPW
WS
WS
DEBOUNCE BY
WAITING FOR
STABLE HIGH, t
READY TO ACCEPT
ANOTHER KEYPRESS
HPW
V
H
V
L
WIPER MOVES HERE
(t
+ tWS)
IPW
2dB
STEPS
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
12 ______________________________________________________________________________________
Mode Control,
MODE
The MAX5457 MODE input toggles between volumeand balance-control modes. Force MODE low to toggle
between volume-control and balance-control modes.
For example, driving MODE low once while in volumecontrol mode, switches the MAX5457 to balance-control mode. Driving mode low once again, switches the
MAX5457 back to volume-control mode. MODE is internally pulled high with a 50kΩ resistor to V
LOGIC
. The
MAX5457 powers up in volume-control mode.
Mode Indicator, MODE_IND
MODE_IND is the volume-control and balance-control
mode indicator with an open-drain output. Connect
MODE_IND to an LED through a pullup resistor to
V
LOGIC
. When the LED is on, the MAX5457 is in balancecontrol mode. When the LED is off, the MAX5457 is in
volume-control mode. See the Mode Control,
MODE
section for more detail on switching between modes.
Shutdown does not affect the state of MODE_IND.
Multiple Button Pushes
The MAX5456/MAX5457 do not respond to simultaneous button pushes. Pushing more than one button at the
same time stops the wipers in their present states. Only
a single button push configures the device. Additionally,
a 40ms blocking period affects all other inputs when
releasing any input forced low. The MAX5456/MAX5457
do not respond to any logic input until the blocking period ends. If multiple wiper-control buttons are pressed,
all wiper-control connections must be released before
the part will respond to further commands.
Applications Information
Stereo Volume/Balance Control
Figure 6 shows a volume/balance application using the
MAX5457. The op amp is connected in a follower (noninverting gain) configuration to isolate the potentiometer’s wiper impedance from the load and provide drive
capability. Connect the W_ of the MAX5457 to the positive input of a noninverting gain amp. The pushbutton
potentiometers attenuate the input signals. Use the
MODE input to switch between volume-control and balance-control modes.
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
______________________________________________________________________________________ 13
Figure 6. Volume/Balance Control
V
DD
V
DD
LEFT CHANNEL IN RIGHT CHANNEL IN
H0
L0
V
LOGIC
V
LOGIC
MODE_INDSHDN
H1
L1
MAX5457
VDD / 2 VDD / 2
W0
GND UP/BAL1 DN/BAL0 MODE
V
DD
LEFT AUDIO
INPUT
MUTEV
SS
RIGHT AUDIO
INPUT
W1
V
DD
MAX4494 MAX4494
INL- INL+ SHDN INR+ INR-
V
DD
SV
DD
PGND
MAX9722
OUTL OUTR
STEREO
HEADPHONE
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
14 ______________________________________________________________________________________
Selector Guide
Pin Configurations (continued)
Chip Information
TRANSISTOR COUNT: 15,395
PROCESS: CMOS
*Future product—contact factory for availability.
PART INTERFACE PKG. CODE
MAX5456EEE 4-Button E16-1
MAX5456ETE* 4-Button T1644-4
MAX5457EEE 3-Button E16-1
MAX5457ETE* 3-Button T1644-4
TOP VIEW
VOLDN
VOLUP
BAL1
BAL0
W0
SHDN
1
2
3
MAX5456
4
H0
5
L0
6
7
8
QSOP
16
V
V
15
GND
14
V
13
H1
12
L1
11
W1
10
MUTE
9
DD
LOGIC
SS
UP/BAL1
16
DN/BAL0
VDDV
15 14 13
VDDV
MUTE
LOGIC
W1
GND
12
V
11
SS
H1
10
L1
9
LOGIC
BAL1
BAL0
H0
VOLUP
VOLDN
16
15 14 13
1
2
MAX5456
3
L0
4
5678
W0
SHDN
TQFN
MODE
MODE_IND
1
2
GND
12
V
11
SS
MAX5457
H0
3
L0
4
5678
W0
SHDN
MUTE
W1
H1
10
L1
9
TQFN
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
______________________________________________________________________________________ 15
Typical Application Circuit (Single Supply)
MAX5456/MAX5457
V
DD
W_
L_
H_
V
DD
R
H
R
L
V
PEAK
0V
V
PEAK
0V
V
PEAK
0V
R
LOAD
= ∞
VSS = -V
DD
V
SS
Typical Application Circuit (Dual Supplies)
V
DD
V
W_
PEAK
V
/ 2
DD
V
PEAK
V
/ 2
DD
H_
R
H
R
L
R
LOAD
= ∞
V
DD
V
PEAK
V
/ 2
DD
MAX5456/MAX5457
L_
V
DD
V
DD
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
16 ______________________________________________________________________________________
Functional Diagrams
V
DD
SHUTDOWN
H0
0
1
2
3
V
LOGIC
CLICK/POP
SUPPRESSION
CIRCUITRY
4
POSITION COUNTER POSITION COUNTER
W0
28
29
DEBOUNCE DEBOUNCE DEBOUNCE DEBOUNCE
30
SHDN
MAX5456
SUPPRESSION
UP/DN UP/DN
TIMING AND CONTROL
CLICK/POP
CIRCUITRY
DEBOUNCE
T F-F
V
LOGIC
SHUTDOWN
0
1
2
3
4
28
29
30
H1
W1
31
32
MUTE
L0
V
GND VOLUP VOLDN BAL0 BAL1
SS
MUTE
31
32
MUTE
L1
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
______________________________________________________________________________________ 17
Functional Diagrams (continued)
V
DD
SHUTDOWN
H0
0
1
2
3
4
W0
28
V
LOGIC
SHDN
MAX5457
CLICK/POP
SUPPRESSION
CIRCUITRY
POSITION COUNTER POSITION COUNTER
UP/DN UP/DN
TIMING AND CONTROL
MODE_IND
CLICK/POP
SUPPRESSION
CIRCUITRY
SHUTDOWN
0
1
2
3
4
28
H1
W1
29
DEBOUNCE DEBOUNCE DEBOUNCE DEBOUNCE
30
31
32
MUTE
L0
V
GND DN/BAL0 UP/BAL1 MODE MUTE
SS
T F-F T F-F
V
LOGIC
29
30
31
32
MUTE
L1
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
18 ______________________________________________________________________________________
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages
.)
QSOP.EPS
PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH
21-0055
1
E
1
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
______________________________________________________________________________________ 19
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages
.)
24L QFN THIN.EPS
PACKAGE OUTLINE,
12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
21-0139
1
E
2
MAX5456/MAX5457
Stereo Audio Taper Potentiometers
with Pushbutton Interface
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages
.)
PACKAGE OUTLINE,
12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
21-0139
2
E
2
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