19-3490; Rev 0; 11/04 Stereo Audio Taper Potentiometers with Pushbutton Interface 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 Typical Application Circuits and Selector Guide appear at end of data sheet. 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 Ordering Information PART TEMP RANGE o MAX5456EEE -40 C to +85 C 16 QSOP MAX5456ETE* -40oC to +85oC 16 TQFN o o MAX5457EEE* -40 C to +85 C 16 QSOP MAX5457ETE* -40oC to +85oC 16 TQFN *Future product—contact factory for availability. Pin Configurations TOP VIEW DN/BAL0 1 16 VDD UP/BAL1 2 15 VLOGIC MODE 3 MODE_IND 4 14 GND MAX5457 13 VSS H0 5 12 H1 L0 6 11 L1 W0 7 10 W1 9 SHDN 8 SPI is a trademark of Motorola, Inc. PIN-PACKAGE o MUTE QSOP SmartWiper is a trademark of Maxim Integrated Products, Inc. Pin Configurations are continued at end of data sheet. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX5456/MAX5457 General Description MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface ABSOLUTE MAXIMUM RATINGS (MAX5456) SHDN, MUTE, VOLUP, VOLDN, BAL_ to GND.....................................-0.3V to (VLOGIC + 0.3V) (MAX5457) SHDN, MUTE, UP/BAL1, DN/BAL0, MODE, MODE_IND to GND...........................-0.3V to (VLOGIC + 0.3V) H_, L_, and W_ to VSS ..............................-0.3V to (VDD + 0.3 V) VDD to GND ..............................................................-0.3V to +6V VDD to VSS ................................................................-0.3V to +6V VLOGIC to GND.........................................................-0.3V to +6V VLOGIC to VSS ...........................................................-0.3V to +6V VSS 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 (TA = +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 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. ELECTRICAL CHARACTERISTICS (VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise specified.) (Note 1) PARAMETER End-to-End Resistance Maximum Bandwidth SYMBOL R fCUTOFF Absolute Ratio Tolerance CONDITIONS Figures 1, 2 MIN TYP MAX UNITS 7 10 13 kΩ From H_ to W_, CLOAD = 10pF No load at the output of the wiper, W_ = -6dB Tap-to-Tap Tolerance VDD = 5V, VH_ = (VDD / 2) + 1VRMS, f = 1kHz, tap = -6dB, VL_ = VDD / 2, RL = ∞ Total Harmonic Distortion Plus Noise THD+N 100 kHz ±0.25 dB ±0.1 dB 0.01 % VDD = 3V, VSS = 0V, VL_ = 1.5V, VH_ = 1.5V + 1VRMS, f = 1kHz, RL = 10kΩ to (VDD / 2), CL = 5pF, tap = -6dB 0.23 Channel-to-Channel Isolation -100 dB ±0.5 dB -90 dB PSRR -80 dB Wiper Resistance RW 1000 Wiper Capacitance CW 10 pF H Terminal Capacitance CH 5 pF L Terminal Capacitance CL Interchannel Matching f = 20Hz to 20kHz, tap = -6dB Mute Attenuation Power-Supply Rejection Ratio 1700 Ω 7 pF End-to-End Resistance Temperature Coefficient 50 ppm/°C Ratiometric Resistance Temperature Coefficient 5 ppm/°C 0.95 µVRMS Output Noise en 20Hz to 20kHz PUSHBUTTON CONTACT INPUTS (UP/BAL1, DN/BAL0, MUTE, VOLUP, VOLDN, BAL0, BAL1, MODE) Internal Pullup Resistor RPULLUP 32 Single Pulse-Width Input tlPW Figure 5 22.5 Repetitive Input Pulse High Time tHPW Figure 5 40 Timeout Period 2 tWS Click/pop suppression inactive 50 65 kΩ ms ms 32 _______________________________________________________________________________________ ms Stereo Audio Taper Potentiometers with Pushbutton Interface (VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. 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 4 Hz Second Autoincrement Point 4 s Second Autoincrement Rate 16 Hz DIGITAL INPUTS (VLOGIC > 4.5V) Input High Voltage VIH Input Low Voltage VIL Input Leakage Current 2.4 V 0.8 Inputs floating ±1 Input Capacitance 5 V µA pF DIGITAL INPUTS (VLOGIC < 4.5V) Input High Voltage VIH Input Low Voltage VIL Input Leakage Current 0.7 x VLOGIC V 0.3 x VLOGIC Inputs floating ±1 Input Capacitance 5 V µA pF POWER SUPPLIES Supply Voltage VDD 2.7 5.5 V Negative Power Supply VSS -2.7 0 V Supply-Voltage Difference Active Supply Current IDD Standby Supply Current ISTBY Shutdown Supply Current ISHDN Power-Up Time VDD - VSS 5.5 V (Note 2) 100 µA VDD = +5.5V, VSS = 0V, VLOGIC = 2.7V (Note 3) 2 10 VLOGIC = VDD = +2.7V, VSS = -2.7V (Note 3) 0.5 1 (Note 4) 1 tPU 10 Logic Standby Voltage VLOGIC Logic Active Supply Current ILOGIC (Note 2) 2.7 Logic Standby Supply Current ILOGICSTBY (Note 3) Logic Shutdown Current ILOGICSHDN (Note 4) 0.5 µA µA ms VDD V 160 µA 1 µA 1 µA DIGITAL OUTPUT, MODE_IND Output Low Voltage VOL Output Leakage Current Output Capacitance Maximum Sink Current VLOGIC = 2.7V, ISINK = 10mA 0.4 VLOGIC = 5.5V, ISINK = 10mA 0.2 0.1 10 V µA 3 pF 150 mA 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. _______________________________________________________________________________________ 3 MAX5456/MAX5457 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise specified.) -10 ATTENUATION (dB) 1050 1000 950 900 850 800 750 700 650 0.5 END-TO-END RESISTANCE CHANGE (%) VDD = VLOGIC = 5V MAX5456/7 toc02 0 MAX5456/7 toc01 1200 1150 1100 END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE ATTENUATION vs. TAP POSITION -20 -30 -40 -50 -60 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 4 WIPER VOLTAGE (V) 8 12 16 20 24 28 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 -40 32 -15 10 35 WIPER SWITCHING TRANSIENT (TIMING OUT) MAX5456/7 toc05a MAX5456/7 toc04 220 VDD = VLOGIC = 5.5V, ILOGIC + IVDD 215 210 5V/div VOLUP VH_ = VDD VL_ = 0 205 200 1V/div 195 WIPER TRANSITION FROM -2dB to 0dB 190 185 180 -40 -15 10 35 60 10ms/div 85 TEMPERATURE (°C) WIPER SWITCHING TRANSIENT (SUPPRESSION CIRCUIT ACTIVE) LOGIC SUPPLY CURRENT vs. LOGIC SUPPLY VOLTAGE MAX5456/7 toc05b MAX5456/7 toc06a 200 VOLUP VH_ = SQUARE WAVE FROM VDD TO VSS, VL_ = VDD / 2 2V/div WIPER TRANSITION FROM -2dB to 0dB LOGIC SUPPLY CURRENT (µA) 180 5V/div 160 ACTIVE LOGIC SUPPLY CURRENT 140 120 100 80 60 40 20 0 4ms/div 2.7 3.2 3.7 4.2 4.7 5.2 5.5 LOGIC SUPPLY VOLTAGE (V) 4 60 TEMPERATURE (°C) TAP POSITION ACTIVE SUPPLY CURRENT vs. TEMPERATURE ACTIVE SUPPLY CURRENT (µA) 0.4 -0.5 -70 600 MAX5456/7 tpc03 WIPER RESISTANCE vs. WIPER VOLTAGE WIPER RESISTANCE (Ω) MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface _______________________________________________________________________________________ 85 Stereo Audio Taper Potentiometers with Pushbutton Interface WIPER-TO-END TERMINAL RESISTANCE vs. TAP POSITION STANDBY LOGIC SUPPLY CURRENT 0.15 0.10 0.05 RWH 75 3.2 3.7 4.2 4.7 W_ SET TO 0dB -2 -4 25 W_ SET TO -6dB -6 RWL 0 -8 0 5.2 5.5 8 16 32 24 0.1 0.01 1 10 100 TAP POSITION FREQUENCY (kHz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY DIGITAL SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE POWER-SUPPLY REJECTION RATIO vs. FREQUENCY 1 LOAD = 10kΩ 0.01 NO LOAD 0.001 100 1000 10,000 -30 600 500 400 100 -80 0 -90 0 1 2 3 4 10 VLOGIC = 5.5V 148 100 1000 FREQUENCY (kHz) SPECTRAL NOISE DENSITY 10 MAX5456/7 toc12 147 9 8 NOISE (nVRMS/√Hz) LOGIC SUPPLY CURRENT (mA) 1 5 DIGITAL INPUT VOLTAGE (V) 150 ACTIVE LOGIC SUPPLY CURRENT 145 -50 -70 200 LOGIC SUPPLY CURRENT vs. TEMPERATURE 146 -40 -60 300 FREQUENCY (Hz) 149 VDD = 5V ±1VP-P, VH_ = 5V, VL_ = 2.5V, W_ SET TO -6dB -20 700 100,000 MAX5456/7 toc11 800 0.0001 10 0 -10 1000 144 143 7 6 5 4 3 142 2 141 1 140 MAX5456 toc13 0.1 900 PSRR (dB) 10 1000 MAX5456/7 toc10 VH_ = 2.5V ±1VP-P, VL_ = 2.5V, W_ SET TO -6dB, 20Hz TO 20kHz BANDPASS DIGITAL SUPPLY CURRENT (µA) MAX5456/7 toc09 LOGIC SUPPLY VOLTAGE (V) 100 THD+N (%) 0 50 0 2.7 VH_ = 2.5V ±1VP-P, VL_ = 2.5V, CL_ = 10pF 2 RESPONSE (dB) 0.20 FREQUENCY RESPONSE MAX5456/7 toc07 0.25 100 NOMINAL END-TO-END RESISTANCE (%RHL) MAX5456/7 toc06b LOGIC SUPPLY CURRENT (µA) 0.30 MAX5456/7 toc08 LOGIC SUPPLY CURRENT vs. LOGIC SUPPLY VOLTAGE 0 -40 -15 10 35 TEMPERATURE (°C) 60 85 0.01 0.1 1 10 100 FREQUENCY (kHz) _______________________________________________________________________________________ 5 MAX5456/MAX5457 Typical Operating Characteristics (continued) (VDD = VLOGIC = +2.7V to +5.5V, VSS = 0V, GND = 0V, VH_ = VDD, VL_ = VSS, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise specified.) MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface Pin Description PIN MAX5457 MAX5456 TQFN QSOP TQFN QSOP 1 3 — — FUNCTION 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 VLOGIC. On power-up, the MAX5457 is in volume-control mode. Volume-Control/Balance-Control Mode Indicator Open-Drain Output. Connect to an LED through a resistor to VLOGIC. When the LED is on, the MAX5457 is in MODE_IND 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. 2 4 — — 3 5 3 5 H0 Potentiometer 0 High Terminal. H0 and L0 terminals can be reversed. 4 6 4 6 L0 Potentiometer 0 Low Terminal. L0 and H0 terminals can be reversed. 5 7 5 7 W0 Potentiometer 0 Wiper Terminal 6 8 6 8 SHDN 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 9 7 9 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 VLOGIC. 8 10 8 10 W1 Potentiometer 1 Wiper Terminal 9 11 9 11 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 VSS Negative Power Supply. Bypass with 0.1µF to ground. 12 14 12 14 GND Ground 13 15 13 15 VLOGIC 14 16 14 16 VDD 15 6 NAME 1 — — Digital Logic Power Supply. Bypass with 0.1µF to ground. Analog Power Supply. Bypass with 0.1µF to ground. DN/BAL0 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 VLOGIC. 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 VLOGIC. 16 2 — — UP/BAL1 — — 1 3 BAL1 Channel 1 Balance-Control Input. Pressing BAL1 moves the balance towards channel 1. BAL1 is internally pulled up with 50kΩ to VLOGIC. — — 2 4 BAL0 Channel 0 Balance-Control Input. Pressing BAL0 moves the balance towards channel 0. BAL0 is internally pulled up with 50kΩ to VLOGIC. — — 15 1 VOLDN Downward Volume-Control Input. Pressing VOLDN moves both wipers towards the L terminals. VOLDN is internally pulled up with 50kΩ to VLOGIC. — — 16 2 VOLUP Upward Volume-Control Input. Pressing VOLUP moves both wipers towards the H terminals. VOLUP is internally pulled up with 50kΩ to VLOGIC. _______________________________________________________________________________________ Stereo Audio Taper Potentiometers with Pushbutton Interface 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 VLOGIC. MAX5456 MAX5457 H_ CH RW R W_ CW L_ CL Figure 1. Potentiometer Model (Active) MAX5456 MAX5457 H_ CH 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. MAX5456/MAX5457 Detailed Description R RW W_ L_ CW CL Figure 2. Potentiometer Model (Shutdown) _______________________________________________________________________________________ 7 MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface BALANCE SEPARATION MAINTAINED H_ W0 W1 W0 W1 PRESS VOLUP TWICE W0 W1 W0 W1 PRESS VOLDN ONCE W0 W1 (a) L_ NO CHANGE PRESS VOLUP ONCE H_ W0 W1 W0 W1 PRESS VOLUP (b) L_ H_ W0 W1 PRESS VOLDN ONCE W0 W1 PRESS VOLDN TO 3d (c) L_ ORIGINAL BALANCE SEPARATION MAINTAINED H_ W0 W1 PRESS VOLUP ONCE FROM 3c W0 W1 PRESS VOLUP ONCE W0 (d) L_ Figure 3. Volume-Control Operation Table 1. Wiper Position and Attenuation ATTENUATION (dB) 0 0 1 2 2 4 … … 6 (POR) 12 … … 8 POSITION 30 60 31 62 32 (mute) >90 _______________________________________________________________________________________ W1 Stereo Audio Taper Potentiometers with Pushbutton Interface 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. CONTACT DURATION t < 22.5ms W0 W1 WIPER ACTION No motion (debouncing). 22.5ms < t ≤ 1s Wiper changes position once. 1s < t ≤ 4s Wiper changes position at a rate of 4Hz. t > 4s Wiper changes position at a rate of 16Hz. VOLUME LEVEL MAINTAINED BALANCE SHIFTS TO W1 VOLUME LEVEL IS SET H_ MAX5456/MAX5457 Table 2. Wiper Action vs. Pushbutton Contact Duration PRESS BAL1 ONCE W0 W1 PRESS BAL1 ONCE W0 W1 (a) L_ H_ VOLUME LEVEL MAINTAINED BALANCE SHIFTS TO W1 VOLUME LEVEL IS SET BY W0 W0 W1 PRESS BAL1 ONCE W0 W1 PRESS BAL1 ONCE W0 W1 (b) L_ Figure 4. Balance-Control Operation _______________________________________________________________________________________ 9 MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface 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 VH_ = 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 V DD - V SS and VLOGIC - 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. SWITCH SWITCH CONTACT CONTACT IS BOUNCING IS STABLE USER PRESSES PUSHBUTTON SWITCH CONTACT IS BOUNCING READY TO ACCEPT ANOTHER KEYPRESS 1 DN OR UP INPUT ACCEPTED 0 tHPW tIPW tWS DEBOUNCE BY WAITING FOR STABLE HIGH, tHPW WAIT FOR DEBOUNCE BY FIRST ZERO WAITING FOR CROSSING, tWS STABLE LOW, tIPW VH VL WIPER MOVES HERE WIPER MOTION 2dB STEPS Figure 5a. Wiper Transition Timing Diagram 10 ______________________________________________________________________________________ Stereo Audio Taper Potentiometers with Pushbutton Interface Mute Function, 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. The MAX5456/MAX5457 feature a mute function. Successive pulses on MUTE toggle its setting. Activating the mute SWITCH SWITCH CONTACT CONTACT IS BOUNCING IS STABLE SWITCH CONTACT IS BOUNCING READY TO ACCEPT ANOTHER KEYPRESS 1 INPUT ACCEPTED 0 tHPW tWS tIPW WAIT FOR DEBOUNCE BY FIRST ZERO WAITING FOR CROSSING OR STABLE LOW, TIMEOUT, tWS tIPW DEBOUNCE BY WAITING FOR STABLE HIGH, tHPW VH VL WIPER MOVES HERE (tIPW + tWS) 2dB STEPS Figure 5b. Wiper Transition Timing Diagram ______________________________________________________________________________________ 11 MAX5456/MAX5457 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. MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface Mode Control, MODE Multiple Button Pushes 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 VLOGIC. The MAX5457 powers up in volume-control mode. 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. 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 VLOGIC. 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. 12 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. ______________________________________________________________________________________ Stereo Audio Taper Potentiometers with Pushbutton Interface VLOGIC VDD LEFT CHANNEL IN MAX5456/MAX5457 VDD SHDN VLOGIC MODE_IND H0 H1 L0 RIGHT CHANNEL IN L1 MAX5457 VDD / 2 VDD / 2 W0 W1 GND VSS MUTE UP/BAL1 DN/BAL0 MODE VDD VDD LEFT AUDIO INPUT RIGHT AUDIO INPUT INL- INL+ SHDN INR+ MAX4494 INR- MAX4494 VDD SVDD PGND MAX9722 OUTL OUTR STEREO HEADPHONE Figure 6. Volume/Balance Control ______________________________________________________________________________________ 13 Selector Guide PART INTERFACE PKG. CODE MAX5456EEE 4-Button E16-1 MAX5456ETE* 4-Button T1644-4 MAX5457EEE 3-Button E16-1 MAX5457ETE* 3-Button T1644-4 Chip Information TRANSISTOR COUNT: 15,395 PROCESS: CMOS *Future product—contact factory for availability. Pin Configurations (continued) 15 VLOGIC 1 BAL0 2 16 15 14 13 12 GND 14 GND 13 VSS 11 L1 W0 7 10 W1 9 SHDN 8 H0 3 10 H1 L0 4 9 MUTE MODE 1 MODE_IND 2 UP/BAL1 DN/BAL0 VDD VLOGIC QSOP 16 15 14 13 5 6 7 8 W1 12 H1 L0 6 MUTE H0 5 11 VSS MAX5456 SHDN MAX5456 W0 BAL1 3 BAL0 4 BAL1 VLOGIC VOLUP 2 VDD 16 VDD VOLDN VOLDN 1 VOLUP TOP VIEW TQFN 12 GND 11 VSS MAX5457 L0 4 9 5 6 7 8 W1 10 H1 MUTE 3 SHDN H0 W0 MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface L1 TQFN 14 ______________________________________________________________________________________ L1 Stereo Audio Taper Potentiometers with Pushbutton Interface VDD VPEAK VDD / 2 RLOAD = ∞ VPEAK VDD / 2 H_ RH VDD W_ VPEAK VDD / 2 RL MAX5456/MAX5457 L_ VDD VDD Typical Application Circuit (Dual Supplies) VDD VPEAK 0V RLOAD = ∞ VPEAK 0V H_ RH VDD W_ VPEAK 0V RL VSS MAX5456/MAX5457 L_ VSS = -VDD ______________________________________________________________________________________ 15 MAX5456/MAX5457 Typical Application Circuit (Single Supply) MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface Functional Diagrams VDD H0 VLOGIC SHDN MAX5456 SHUTDOWN SHUTDOWN CLICK/POP SUPPRESSION CIRCUITRY 0 CLICK/POP SUPPRESSION CIRCUITRY H1 0 1 1 2 2 3 3 4 4 POSITION COUNTER POSITION COUNTER W0 W1 UP/DN UP/DN 28 28 TIMING AND CONTROL T F-F 29 DEBOUNCE DEBOUNCE DEBOUNCE DEBOUNCE 29 DEBOUNCE VLOGIC 30 30 31 31 32 32 MUTE MUTE L0 L1 VSS 16 GND VOLUP VOLDN BAL0 BAL1 MUTE ______________________________________________________________________________________ Stereo Audio Taper Potentiometers with Pushbutton Interface VDD H0 VLOGIC MODE_IND SHDN MAX5457 SHUTDOWN SHUTDOWN CLICK/POP SUPPRESSION CIRCUITRY 0 CLICK/POP SUPPRESSION CIRCUITRY 1 1 2 2 3 3 4 H1 0 4 POSITION COUNTER POSITION COUNTER W0 W1 UP/DN UP/DN 28 28 TIMING AND CONTROL 29 DEBOUNCE DEBOUNCE T F-F T F-F DEBOUNCE DEBOUNCE 29 VLOGIC 30 30 31 31 32 MUTE 32 MUTE L0 L1 VSS GND DN/BAL0 UP/BAL1 MODE MUTE ______________________________________________________________________________________ 17 MAX5456/MAX5457 Functional Diagrams (continued) 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 MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH 21-0055 18 ______________________________________________________________________________________ E 1 1 Stereo Audio Taper Potentiometers with Pushbutton Interface 24L QFN THIN.EPS PACKAGE OUTLINE, 12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm 21-0139 D 1 2 ______________________________________________________________________________________ 19 MAX5456/MAX5457 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.) MAX5456/MAX5457 Stereo Audio Taper Potentiometers with Pushbutton Interface 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 D 2 2 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 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.