19-2049; Rev 0; 5/01 Dual-Audio, Log Taper Digital Potentiometers Applications Features ♦ Log Taper with 2dB Steps Between Taps ♦ 32-Tap Positions for Each Wiper ♦ Small 16-Pin QSOP/QFN Packages ♦ +2.7V to +3.6V Single-Supply Operation ♦ Low 1µA Supply Current ♦ Zero-Crossing Detection for Clickless Switching ♦ Mute Function to -90dB ♦ 10kΩ Fixed Resistance Value ♦ 3-Wire SPI-Compatible Serial Data Interface ♦ Power-On Reset: Wiper Goes to Maximum Attenuation ♦ Digital Output for Readback and Daisy-Chaining Capabilities Stereo Volume Control Ordering Information Fading and Balancing Stereo Signals PART Mechanical Potentiometer Replacement TEMP. RANGE MAX5408EEE SPI is a trademark of Motorola Inc. Functional Diagram appears at end of data sheet. PINPACKAGE WIPERS PER RESISTOR -40°C to +85°C 16 QSOP 1 MAX5408EGE -40°C to +85°C 16 QFN 1 MAX5409EEE -40°C to +85°C 16 QSOP 2 MAX5409EGE -40°C to +85°C 16 QFN 2 Pin Configurations DIN 2 15 VLOGIC SCLK 3 VDD VLOGIC SCLK 1 CS 2 12 GND 11 AGND 15 14 13 14 GND MAX5408 MAX5409 L0 6 13 AGND 12 H1 MAX5408 MAX5409 11 L1 H0 3 10 H1 L0 4 9 L1 N.C. (W0B) 8 9 N.C. (W1B) 5 QSOP (5mm x 6mm) W0A N.C. (W0B) N.C. (W1B) 8 10 W1A 7 W0A 7 6 H0 5 DOUT 16 VDD DOUT 1 CS 4 DIN 16 TOP VIEW W1A ( ) ARE FOR MAX5409 ONLY QFN (4mm x 4mm) ________________________________________________________________ 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 MAX5408/MAX5409 General Description The MAX5408/MAX5409 are dual logarithmic taper digital potentiometers with 32-tap points each. The MAX5408 is a dual potentiometer with one wiper per potentiometer. The MAX5409 is a dual potentiometer with two wipers per potentiometer (see Functional Diagram). An SPI™-compatible serial interface controls the wipers. The MAX5408/MAX5409 have a factory-set resistance of 10kΩ per potentiometer. A zero-crossing detect feature minimizes the audible noise generated by wiper transitions. These devices are ideal for audio applications requiring digitally controlled resistors. The MAX5408/MAX5409 have nominal resistor temperaturecoefficients of 35ppm/°C end-to-end and 5ppm/°C ratiometric. The MAX5408/MAX5409 are available in 16-pin QSOP and 16-pin QFN packages and are specified over the extended temperature range (-40°C to +85°C). MAX5408/MAX5409 Dual-Audio, Log Taper Digital Potentiometers ABSOLUTE MAXIMUM RATINGS VDD, VLOGIC, CS, SCLK, DIN to GND ......................-0.3V to +6V H_, L_, and W_ to GND ..............................-0.3V to (VDD + 0.3V) DOUT to GND.............................................-0.3V to (VDD + 0.3V) AGND to GND .......................................................-0.3V to +0.3V Input and Output Latchup Immunity...............................±200mA Maximum Continuous Current into H_, L_, and W_.........±500µA Continuous Power Dissipation (TA = +70°C) QSOP (derate 8.3mW/°C above +70°C) ...................666.7mW QFN (derate 18.5mW/°C above +70°C) ....................1481mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-60°C to +150°C Maximum Junction Temperature .....................................+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 = +2.7V to +3.6V, VH_ = VLOGIC, VL_ = 0, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise specified.) PARAMETER SYMBOL CONDITIONS End-to-End Resistance Maximum Bandwidth MIN TYP MAX UNITS 7 10 13 Ω 100 kHz Absolute Tolerance ±0.25 dB Tap-to-Tap Tolerance ±0.1 dB Total Harmonic Distortion THD VIN = 1VRMS, f = 1kHz, tap = -6dB Channel Isolation Interchannel Matching f = 20Hz to 20kHz, tap = -6dB Mute Attenuation Power-Supply Rejection Ratio 0.002 % -100 dB ±0.5 dB -90 dB PSRR -80 Wiper Resistance RW 1000 Wiper Capacitance CW Digital Clock Feedthrough End-to-End Resistance Tempco fSCLK = 20Hz to 20kHz, tap = -6dB TCR Ratiometric Resistance Tempco dB 1700 Ω 10 pF -90 dB 35 ppm/°C 5 ppm/°C DIGITAL INPUTS (VLOGIC > 4.5V) Input High Voltage VIH Input Low Voltage VIL 2.4 V Input Leakage Current Input Capacitance 0.8 V ±1 µA 5 pF DIGITAL INPUTS (VLOGIC < 4.5V) Input High Voltage VIH Input Low Voltage VIL 0.7 x VLOGIC V Input Leakage Current Input Capacitance 0. 3 x VLOGIC V ±1 µA 5 pF DIGITAL OUTPUT Output High Voltage VOH ISOURCE = 0.5mA Output Low Voltage VOL ISINK = 2mA 2 VLOGIC - 0.5 _______________________________________________________________________________________ V 0.4 V Dual-Audio, Log Taper Digital Potentiometers (VDD = +2.7V to +3.6V, VH_ = VLOGIC, VL_ = 0, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise specified.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS TIMING CHARACTERISTICS (Figure 1) SCLK Clock Period tCP 100 ns SCLK Pulse Width High tCH 40 ns SCLK Pulse Width Low tCL 40 ns CS Fall to SCLK Rise Setup Time tCSS 40 ns SCLK Rise to CS Rise Hold Time tCSH 0 ns DIN Setup Time tDS 40 ns DIN Hold Time tDH 0 ns SCLK Fall to DOUT Valid Propagation Delay tDO CS Rise to SCLK Rise Hold Time tCS1 CS Pulse Width High tCSW Wiper Settling Time POWER SUPPLIES tIW Supply Voltage CLOAD = 200pF 40 Standby Supply Current Logic Supply Voltage Logic Active Supply Current Logic Standby Supply Current IDD 2.7 3.6 fSCLK = 2MHz, (Note 1) VLOGIC ILOGIC ns 100 0.2 2.7 10 5.5 fSCLK = 2MHz, DOUT = floating (Note 3) DOUT = floating (Note 2) µs 1 (Note 2) ns ns 100 Zero-Crossing Detect disabled VDD Active Supply Current 80 120 1 10 V µA V µA Note 1: Supply current measured while changing, wiper position with zero-crossing enabled. Note 2: Supply current measured while wiper position is fixed. Note 3: Supply current measured changing wiper position. _______________________________________________________________________________________ 3 MAX5408/MAX5409 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VDD = 5V, TA = +25°C, unless otherwise specified) WIPER RESISTANCE vs. WIPER VOLTAGE END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE 994 993 992 991 990 989 VDD = 5V = VLOGIC, L_ = GND 988 MAX5408 toc02 0.20 END-TO-END RESISTANCE CHANGE (%) TAP POSITION 31 995 0.15 0.10 0.05 0 -0.05 -0.10 -0.15 -0.20 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -40 -15 10 35 60 WIPER VOLTAGE (V) TEMPERATURE (°C) ATTENUATION vs. TAP POSITION SUPPLY CURRENT vs. TEMPERATURE 15 MAX5408 toc03 0 I = IDD + ILOGIC 12 SUPPLY CURRENT (µA) -10 -20 -30 -40 -50 85 MAX5408 toc04 WIPER RESISTANCE (Ω) MAX5408 toc01 996 ATTENUATION (dB) 9 6 3 -60 VDD = VLOGIC = 5V -70 0 4 8 12 16 20 24 28 32 -40 -15 10 35 TAP POSITION TEMPERATURE (°C) TAP-TO-TAP SWITCHING TRANSIENT (ZERO-CROSSING DISABLE) LOGIC CURRENT vs. LOGIC VOLTAGE MAX5408 toc05 0.30 VW__ 2V/div STANDBY SCLK = GND 0.25 CS 2V/div VH_ = 5V VL_ = 0 60 85 MAX5408 toc06 0 SUPPLY CURRENT (µA) MAX5408/MAX5409 Dual-Audio, Log Taper Digital Potentiometers 0.20 0.15 0.10 0.05 0 4µs/div 2.5 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 4 _______________________________________________________________________________________ 5.5 Dual-Audio, Log Taper Digital Potentiometers LOGIC CURRENT vs. LOGIC VOLTAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE 0.50 ZERO-CROSSING DETECTION DISABLED 0.45 35 0.40 30 0.35 IDD (µA) SUPPLY CURRENT (µA) 40 MAX5408 toc08 ACTIVE MODE SCLK = 2MHz, O to VLOGIC 45 0.55 MAX5480 toc07 50 25 20 0.30 ACTIVE 0.25 0.20 15 STANDBY 0.15 10 0.10 5 0.05 0 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 2.5 SUPPLY VOLTAGE (V) 3.0 3.5 4.0 4.5 5.0 5.5 VDD (V) Pin Description PIN MAX5408 QFN MAX5408 QSOP MAX5409 QFN MAX5409 QSOP NAME FUNCTION 1 3 1 3 SCLK 2 4 2 4 CS Chip Select for Wiper Control Serial Data Clock Input 3 5 3 5 H0 High Terminal of Resistor 0 4 6 4 6 L0 Low Terminal of Resistor 0 5 7 5 7 W0A Wiper Terminal A of Resistor 0 — — 6 8 W0B Wiper Terminal B of Resistor 0 — — 7 9 W1B Wiper Terminal B of Resistor 1 8 10 8 10 W1A Wiper Terminal A of Resistor 1 9 11 9 11 L1 Low Terminal of Resistor 1 10 12 10 12 H1 High Terminal of Resistor 1 11 13 11 13 AGND 12 14 12 14 GND 13 15 13 15 VLOGIC Power Supply for Interface Logic 14 16 14 16 VDD Power Supply for Wiper Switches 15 1 15 1 DOUT 16 2 16 2 DIN Serial Data In 6, 7 8, 9 — — N.C Not Connected Analog Ground Ground Serial Data Out _______________________________________________________________________________________ 5 MAX5408/MAX5409 Typical Operating Characteristics (continued) (VDD = 5V, TA = +25°C, unless otherwise specified) MAX5408/MAX5409 Dual-Audio, Log Taper Digital Potentiometers Table 1. Serial Interface Programming Commands for MAX5408 8-BIT SERIAL WORD FUNCTION A0 A1 A2 D4–D0 0 0 0 5-bit DAC Data Program position of wiper W0A 0 0 1 5-bit DAC Data Undefined 0 1 0 5-bit DAC Data Program position of wiper W1A 0 1 1 5-bit DAC Data Undefined 1 0 0 4-bit Mute Data, D0 = “don’t care” Data for mute register (see Table 3) 1 0 1 4-bit Zero-Crossing Detection Data, D0 = “don’t care” Data for zero-crossing detection register (see Table 5) 1 1 0 00000 Return wiper register for W0A 1 1 0 00001 Undefined 1 1 0 00010 Return wiper register for W1A 1 1 0 00011 Undefined 1 1 0 00100 Return mute register 1 1 0 00101 Return zero-crossing detection register 1 1 1 D4 = 0, D3–D0 = “don’t care Analog power-down 1 1 1 D4 = 1, D3–D0 = “don’t care” Analog power-up Detailed Description CS Digital Serial Interface An SPI-compatible serial interface controls the MAX5408/MAX5409. The input word to the device is eight bits long, composed of three address bits (A0, A1, and A2), followed by five data bits, with MSB first (see Tables 1 and 2). The first three address bits set the value of internal registers. The five data bits control the wiper position. For certain commands, some of the five data bits are “don’t cares”, but must be sent to the device. The serial data is listed in Tables 1 and 2. The control code determines: • Potentiometer to update or register to set. • Data for mute register (Tables 3 and 4). • Data for zero-crossing detection register (Tables 5 and 6). The data bits control the position of the wiper (Table 7). A logic low on the chip-select input (CS) enables the device’s serial interface. A logic high on CS disables the interface control circuitry. See Figure 1 for serialinterface timing description. tCSS tCL tCH SCLK tDS tDH SDIN DOUT tCSW CS tCSH tCP tCSI SCLK SDIN tDO DOUT tIW WIPER Figure 1. Serial Timing Diagram 6 _______________________________________________________________________________________ Dual-Audio, Log Taper Digital Potentiometers MAX5408/MAX5409 Table 2. Serial Interface Programming Commands for MAX5409 8-BIT SERIAL WORD FUNCTION A0 A1 A2 D4–D0 0 0 0 5-bit DAC Data Program position of wiper W0A 0 0 1 5-bit DAC Data Program position of wiper W0B 0 1 0 5-bit DAC Data Program position of wiper W1A 0 1 1 5-bit DAC Data Program position of wiper W1B 1 0 0 4-bit Mute Data, D0 = “don’t care” Data for mute register (see Table 4) 1 0 1 4-bit Zero-Crossing Detection Data, D0 = “don’t care” Data for zero-crossing detection register (see Table 6) 1 1 0 00000 Return wiper register for W0A 1 1 0 00001 Return wiper register for W0B 1 1 0 00010 Return wiper register for W1A 1 1 0 00011 Return wiper register for W1B 1 1 0 00100 Return mute register 1 1 0 00101 Return zero-crossing detection register 1 1 1 D4 = 0, D3–D0 = “don’t care Analog power-down 1 1 1 D4 = 1, D3–D0 = “don’t care” Analog power-up Table 3. Mute Register Bit Definitions for MAX5408 DATA BIT D4 D3 D2 VALUE FUNCTION 0 Set wiper W0A to preprogrammed value (-62dB on power-up) 1 Set wiper W0A to L0 “don’t care” Undefined 0 Set wiper W1A to preprogrammed value (-62dB on power-up) 1 Set wiper W1A to L0 D1 “don’t care” Undefined D0 “don’t care” Undefined Table 4. Mute Register Bit Definitions for MAX5409 DATA BIT D4 D3 D2 D1 D0 VALUE FUNCTION 0 Set wiper W0A to preprogrammed value (-62dB on power-up) 1 Set wiper W0A to L0 0 Set wiper W0B to preprogrammed value (-62dB on power-up) 1 Set wiper W0B to L0 0 Set wiper W1A to preprogrammed value (-62dB on power-up) 1 Set wiper W1A to L1 0 Set wiper W1B to preprogrammed value (-62dB on power-up) 1 Set wiper W1B to L1 “don’t care” Undefined _______________________________________________________________________________________ 7 MAX5408/MAX5409 Dual-Audio, Log Taper Digital Potentiometers Table 5. Zero-Crossing Detection Register Bit Definitions for MAX5408 DATA BIT VALUE FUNCTION 0 D4 Disable wiper W0A zero-crossing detection circuit 1 D3 Enable wiper W0A zero-crossing detection circuit “don’t care” 0 D2 Undefined Disable wiper W1A zero-crossing detection circuit 1 Enable wiper W1A zero-crossing detection circuit D1 “don’t care” Undefined D0 “don’t care” Undefined Table 6. Zero-Crossing Detection Register Bit Definitions for MAX5409 DATA BIT VALUE D4 D3 D2 D1 D0 FUNCTION 0 Disable wiper W0A zero-crossing detection circuit 1 Enable wiper W0A zero-crossing detection circuit 0 Disable wiper W0B zero-crossing detection circuit 1 Enable wiper W0B zero-crossing detection circuit 0 Disable wiper W1A zero-crossing detection circuit 1 Enable wiper W1A zero-crossing detection circuit 0 Disable wiper W1B zero-crossing detection circuit 1 Enable wiper W1B zero-crossing detection circuit “don’t care” Undefined Table 7. Attenuation and Wiper Position POSITION OUTPUT LEVEL (dB) 0 0 1 -2 2 -4 3 -6 4 .. .. . -8 .. .. . 30 -60 31 -62 MUTE <-90 The digital output, DOUT, lags the digital input signal, DIN by 8.5 clock cycles. Force CS high to disable DOUT, placing DOUT in three-state mode. Force CS low to enable DOUT and disable three-state mode. Force CS high, after a word has been written to the MAX5408/MAX5409 to make a readback request. The next CS low period writes the requested data to DOUT. 8 A readback request overwrites any previous data in the shift register. Note that the data appears at DOUT in the order: A0, A1, A2, D4, D3, D2, D1, D0. A0 will be available after the first high-to-low transition of SCLK when CS is low. The input continues to load the shift register while data is being read out of the MAX5408/ MAX5409. The input data appears at DOUT 8.5 clock cycles later. A CS transition from low-to-high latches the input data. For any control byte, the state of SCLK must be the same for both CS low-to-high transitions and CS high-to-low transitions, in order to preserve the data at DOUT while CS transitions. Zero-Crossing Detection The zero-crossing detection register enables the zerocrossing detect feature. The zero-crossing detect feature reduces the audible noise (“clicks and pops”) that result from wiper transitions. The wiper changes position only when the voltage at L_ is the same as the voltage at H_. The MAX5408/MAX5409 timeout and change the wiper position, if after 50ms no zero-crossing is detected. _______________________________________________________________________________________ Dual-Audio, Log Taper Digital Potentiometers Mute Function When mute is enabled, the wiper stays at its previous position. If a command to update the wiper position is issued when the device is in mute, the wiper will be set to its new position when mute is removed. with a fixed gain. The digitally controlled potentiometer attenuates the input signal. Stereo Volume Control Figure 3 shows the application of stereo volume control. The op amps are connected in a follower configuration with fixed gain. The digitally controlled potentiometer attenuates the input signals. The second wiper of each potentiometer controls the signal amplitude at the rear set of speakers. Applications Information Daisy-Chaining Attenuation Control Figure 2 shows the application of an attenuation control. The op amps are connected in a follower configuration VOUT0 VIN0 VIN1 H0 H1 W0A Gain Control W1A MAX5408 MAX5409 Figure 4 shows an application daisy-chaining the serial-interfaces of the MAX5408/MAX5409. A singlewrite command updates multiple devices from a single digital port in this configuration (see Digital Serial Interface section). Figure 5 shows the application of a gain control. Note: Muting the potentiometer creates unpredictable behavior at the output of the op amp, and may seriously degrade the performance of the op amp. VOUT1 L1 L0 Figure 2. Attenuation Control VLEFTF W0A VLEFT VRIGHT H0 H1 VRIGHTF W1A MAX5409 VLEFTR W0B W1B L0 VRIGHTR L1 Figure 3. Stereo Volume Control with Front and Rear Fade _______________________________________________________________________________________ 9 MAX5408/MAX5409 Power-On Reset The power-on reset (POR) feature sets the wiper to the maximum attenuation (tap position 31, -62 dB) at powerup. MAX5408/MAX5409 Dual-Audio, Log Taper Digital Potentiometers SCLK H1 H0 SCLK SDIN SDIN CS SCLK DOUT MAX5408 MA5409 SCLK SDIN CS DOUT MAX5408 MA5409 SDIN CS VIN0 DOUT VOUT0 VIN1 W0A MAX5408 MA5409 W1A MAX5408 MAX5409 L0 L1 CS Figure 4. Daisy-Chaining of Serial Interfaces Figure 5. Gain Control Chip Information TRANSISTOR COUNT: 12759 PROCESS: BiCMOS 10 ______________________________________________________________________________________ VOUT1 Dual-Audio, Log Taper Digital Potentiometers W0A H0 N.C.(W0B) DOUT W1A H1 N.C.(W1B) MAX5408 MAX5409 32 POSITION DECODER/ REGISTER AUDIO ZEROCROSSING DETECTOR SPI LOGIC VLOGIC VDD L0 SCLK SDIN CS L1 GND AGND ( ) ARE FOR MAX5409 ONLY ______________________________________________________________________________________ 11 MAX5408/MAX5409 Functional Diagram Package Information 12, 16,20, 24L QFN.EPS MAX5408/MAX5409 Dual-Audio, Log Taper Digital Potentiometers 12 _______________________________________________________________________________________ Dual-Audio, Log Taper Digital Potentiometers QSOP,EXP. PADS.EPS 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. 13 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX5408/MAX5409 Package Information (continued)