Rev 0; 8/03 Nonvolatile, 32-Position Digital Potentiometer Features The DS4301 is a single 32-position linear digital potentiometer with 200kΩ end-to-end resistance. The wiper setting is stored in EEPROM, so the DS4301 powers up with the last stored setting. The position of the wiper is controlled through a simple three-terminal increment/decrement interface. The DS4301 is ideal for white LED backlight brightness control. Its 8-pin µSOP package, 2.4V to 5.5V supply range, and 200kΩ endto-end resistance are especially suited for portable, battery-powered applications such as cellular telephones and PDAs. ♦ Single, 32-Position, 200kΩ Linear Nonvolatile (NV) Potentiometer Ideal for Battery-Powered Applications ♦ Three-Terminal Increment/Decrement Interface to Adjust Wiper Position ♦ Wide Voltage Supply Range (2.4V to 5.5V) ♦ Command-Initiated NV Wiper Storage ♦ Operates Over the Industrial Temperature Range (-40°C to +85°C) ♦ Available in 8-Pin µSOP Ordering Information Applications White LED Backlight Brightness Control PART Portable Battery-Powered Devices such as PDAs and Cellular Phones DS4301U-200 TEMP RANGE PIN-PACKAGE -40°C to +85°C 8 µSOP (118 mil) Any Application that Requires a Small, Low-Cost NV Potentiometer Pin Configuration TOP VIEW INC 1 8 VCC U/D 2 7 CS H 3 6 L GND 4 5 W DS4301 µSOP Typical Operating Circuit VCC VCC 0.1µF VREF H VCC DS4301 CONTROL INTERFACE CS INC U/D W GND MBR0540 1µF 10µF 1µF EXT VCC ADJ L 10µH VCC WHITE LED CURRENT REGULATOR GND WHITE LEDs CS FB PGND RFB ______________________________________________ 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 DS4301 General Description DS4301 Nonvolatile, 32-Position Digital Potentiometer ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC Pin Relative to Ground .....-0.5V to +6.0V Voltage Range on CS, INC, U/D, L, W, H Pins Relative to Ground*.....................................-0.5V to VCC + 0.5V Wiper Current .....................................................................±3mA Operating Temperature Range ...........................-40°C to +85°C Programming Temperature.....................................0°C to +70°C Storage Temperature Range .............................-55°C to +125°C Soldering Temperature .......................................See IPC/JEDEC J-STD-020A Specification *Not to exceed 6.0V 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. RECOMMENDED DC OPERATION CONDITIONS (VCC = VCC MIN to VCC MAX; TA = -40°C to +85°C, unless otherwise specified.) PARAMETER SYMBOL Supply Voltage VCC Input Logic 1 (CS, INC, U/D) VIH Input Logic 0 (CS, INC, U/D) VIL Resistor Inputs Wiper Current CONDITIONS (Note 1) MIN TYP +2.4 0.7 x VCC MAX UNITS +5.5 V VCC + 0.3 V -0.3 +0.3 x VCC V L, H, W -0.3 VCC + 0.3 IW -1 V +1 mA MAX UNITS +1 µA DC ELECTRICAL CHARACTERISTICS (VCC = VCC MIN to VCC MAX; TA = -40°C to +85°C, unless otherwise specified.) PARAMETER Input Leakage SYMBOL CONDITIONS IL Standby Current (Note 2) ISTBY Digital Input Capacitance CI/O MIN TYP -1 3V 30 60 5V 15 60 µA 10 pF MAX UNITS +20 % ANALOG RESISTOR CHARACTERISTICS (VCC = VCC MIN to VCC MAX; TA = -40°C to +85°C, unless otherwise specified.) PARAMETER SYMBOL End-to-End Resistor Tolerance CONDITIONS MIN TYP TA = +25°C -20 2000 Ω Absolute Linearity (Note 3) -0.5 +0.5 LSB Relative Linearity (Note 4) -0.25 +0.25 LSB +250 ppm/°C Wiper Resistance RW 500 End-to-End Temp Coefficient Ratiometric Temp Coefficient 2 _____________________________________________________________________ -250 7 ppm/°C Nonvolatile, 32-Position Digital Potentiometer (VCC = VCC MIN to VCC MAX; TA = -40°C to +85°C. See Figure 2 for timing diagram.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS CS to INC Setup tCI 50 ns U/D to INC Setup tDI 100 ns INC Low Period tIL 50 ns INC High Period tIH 100 ns INC Inactive to CS Inactive tIC 500 ns tCPH 100 CS Deselect Time Wiper Change to INC Low INC Rise and Fall Times INC Low to CS Inactive Wiper Storage Time ns tIW 200 ns tR, tF 5 µs 10 ms tIK (Note 5) tWST (Note 6) 50 ns CS Low Pulse tCLP Wiper Load Time tWLT (Note 7) 500 µs tPU (Note 8) 2 ms Power-Up Time 100 ns NONVOLATILE MEMORY CHARACTERISTICS (VCC = VCC MIN to VCC MAX) PARAMETER EEPROM Write Cycles Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: SYMBOL CONDITIONS +70°C (Note 9) MIN TYP MAX UNITS 50,000 All voltages are referenced to ground. STBY specified for VCC equal to 3.0V and 5.0V while control port logic pins are driven to VCC or GND. Absolute linearity is used to determine wiper voltage versus expected voltage as determined by wiper position. Relative linearity is used to determine the change of wiper voltage between two adjacent wiper positions. The INC low to CS inactive time is the transition time that allows the three control pins to become inactive without writing the wiper position to the EEPROM. Wiper storage time is the time required for the wiper position to be written to the EEPROM. During this time, the three-terminal interface is inactive. Wiper load time is specified as the time required to load the wiper position stored in EEPROM once VCC has reached a stable operating voltage greater than or equal to VCC MIN. Power-up time is specified as the time required before the three control pins become active once a stable power supply level of at least VCC MIN has been reached. The maximum number of EEPROM write cycles is guaranteed by design and is not tested in production. _____________________________________________________________________ 3 DS4301 AC ELECTRICAL CHARACTERISTICCS Typical Operating Characteristics (VCC = 5.0V; TA = +25°C, unless otherwise noted.) 25 25 20 15 10 VCC = 3V 200 20 15 VCC = 5V 10 AT VCC = 5V AND 3V 175 W-L RESISTANCE (kΩ) SUPPLY CURRENT (µA) 30 DS4301 toc02 CS = INC = U/D = VCC 150 125 100 75 50 5 25 CS = INC = U/D = VCC 0 0 0 0 1 2 3 4 -40 5 -15 10 35 TEMPERATURE (°C) W-L RESISTANCE vs. SUPPLY VOLTAGE (POWER-UP) W-L RESISTANCE vs. SUPPLY VOLTAGE (POWER-DOWN) 250 DS4301 toc04 >1MΩ 200 W-L RESISTANCE (kΩ) 150 WIPER = POS 15 100 EEPROM RECALL 50 10 15 20 25 30 WIPER RESISTANCE vs. WIPER VOLTAGE 400 350 WIPER RESISTANCE (Ω) >1MΩ 200 5 POTENTIOMETER SETTING (DEC) VOLTAGE (V) 250 0 85 60 150 WIPER = POS 15 100 DS4301 toc06 POWER-UP POWER-DOWN 5 DS4301 toc05 SUPPLY CURRENT (µA) 30 DS4301 toc01 35 W-L RESISTANCE (kΩ) W-L RESISTANCE vs. POTENTIOMETER SETTING SUPPLY CURRENT vs. TEMPERATURE DS4301 toc03 SUPPLY CURRENT vs. VOLTAGE 50 300 VCC = 3V 250 VCC = 5V 200 150 100 50 0 0 1 2 3 4 5 1 2 3 4 5 0 1 2 3 4 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) WIPER VOLTAGE (V) ABSOLUTE LINEARITY vs. WIPER POSITION RELATIVE LINEARITY vs. WIPER POSITION VOLTAGE DIVIDER PERCENT CHANGE FROM +25°C vs. TEMPERATURE ABSOLUTE LINEARITY (LSB) 0.15 0.20 0.10 0.05 0 -0.05 -0.10 0.05 0.15 0.10 0.05 0 -0.05 -0.10 0.03 0.02 0 -0.01 -0.02 -0.20 -0.04 -0.25 -0.25 -0.05 10 20 30 WIPER = POS 7 tc = 2.72ppm/°C -0.03 -0.15 -0.20 WIPER POSITION (DEC) 0 10 20 30 WIPER POSITION (DEC) _____________________________________________________________________ 5 WIPER = POS 15 tc = 0.64ppm/°C 0.01 -0.15 0 WIPER = POS 15 tc = 1.37ppm/°C WIPER = POS 7 tc = 2.72ppm/°C 0.04 % CHANGE (FROM +25°C) 0.20 DS4301 toc08 0.25 DS4301 toc07 0.25 4 0 0 DS4301 toc09 0 ABSOLUTE LINEARITY (LSB) DS4301 Nonvolatile, 32-Position Digital Potentiometer -40 -15 10 WIPER = POS 23 tc = 0ppm/°C 35 TEMPERATURE (°C) 60 85 Nonvolatile, 32-Position Digital Potentiometer END-TO-END RESISTANCE PERCENT CHANGE FROM +25°C vs. TEMPERATURE % CHANGE (FROM +25°C) 3 2 -37.18ppm/°C = tc 1 0 -148.38ppm/°C = tc -1 -2 -3 -4 10 8 25°C TO 85°C +25°C TO -40°C 6 DS4301 toc11 4 TEMPERATURE COEFFICIENT (ppm/°C) DS4301 toc10 5 TEMPERATURE COEFFICIENT vs. POTENTIOMETER SETTING 4 2 0 -2 -4 -6 -8 -5 -10 -40 -20 0 20 40 60 80 0 TEMPERATURE (°C) 5 10 15 20 25 30 POTENTIOMETER SETTING (DEC) Pin Description PIN NAME FUNCTION 1 INC Increment/Decrement Wiper Control. When INC transitions from high-to-low, the wiper moves in the direction established by the state of the U/D pin. 2 U/D Up/Down Control. Sets the directions of wiper movement. When set to a high state, a high-to-low transition on the INC pin increments the wiper. When set to a low state, a high-to-low transition on the INC pin decrements the wiper. 3 H 4 GND 5 W Wiper Terminal of the Potentiometer 6 L Low-End Terminal of the Potentiometer 7 CS Chip Select. When set to a low state, the wiper position can be adjusted using U/D and INC. When in a high-state, activity on INC and U/D does not affect or change the wiper position. 8 VCC Power Supply Terminal High-End Terminal of the Potentiometer Ground Terminal _____________________________________________________________________ 5 DS4301 Typical Operating Characteristics (continued) (VCC = 5.0V; TA = +25°C, unless otherwise noted.) Nonvolatile, 32-Position Digital Potentiometer DS4301 Wiper Control VCC H POS 31 VCC CS INC U/D 5-BIT WIPER SETTING CONTROL LOGIC UNIT POS 0 GND NONVOLATILE MEMORY L W Figure 1. Block Diagram Detailed Description The DS4301 is a single nonvolatile digital potentiometer. This 32-position linear potentiometer has an end-toend resistance of 200kΩ, and operates over a wide 2.4V to 5.5V supply voltage range. The wiper position is controlled by the three interface pins (U/D, CS, and INC), and the wiper setting can be stored in EEPROM on command. Power-Up On power-up, once a stable supply voltage of VCC MIN has been reached, the stored wiper setting is loaded from the EEPROM within tWLT. Also on power-up, the DS4301 wiper control pins become active approximately t PU after a stable supply voltage of V CC MIN has been reached. Adjusting the wiper of the DS4301 involves using the three control pins (U/D, CS, and INC). See the Timing Diagram in Figure 2. To enable wiper adjustment, a high-to-low transition on the CS pin is required. Hold CS low for the duration of the communication. Doing this enables the INC pin to change the wiper position. Set the U/D pin high to increment or low to decrement the wiper position. The state of the U/D pin should be set more than tDI before the INC signal is transitioned from high to low. After the CS pin is active low, a highto-low transition on the INC pin moves the wiper in the direction dictated by the U/D pin. Continue to pulse INC (high to low) until the desired wiper position is reached. On the last edge, hold the INC line low. With the desired wiper position set, there are two ways to proceed. One method terminates communication without allowing the value of the current wiper position to be written to the EEPROM. This is done by transitioning the CS signal to the high state before bringing the INC signal high. As long as the state of the CS pin is high before the state of the INC pin goes high, the current wiper setting is not written to EEPROM. Because the current wiper setting was not stored to the NV memory, the previously stored wiper setting, not the current wiper setting, is loaded from memory if power is cycled to the device The other method is used to store a new wiper setting in the EEPROM. This is done by bringing the state of the INC pin high for a time of tIC before bringing the state of the CS pin high. Once the states of both CS and INC pins are high, the current wiper setting is stored in EEPROM after a time of t WST. If power is WIPER STORAGE CONDITION WIPER NON-STORAGE CONDITION CS VIH tCPH VIL INC tCI tIH tIL VIH tWST tF tIC tIK VIL tDI U/D tR VIL tIW POSITION X WIPER POSITION tIW POSITION X + 1 POSITION X POSITION X - 1 Figure 2. Timing Diagram 6 _____________________________________________________________________ tCLP Nonvolatile, 32-Position Digital Potentiometer Wiper storage does not have to occur immediately after a change in wiper position. At anytime the current wiper position can be stored to the EEPROM by simply issuing a low pulse to the CS pin for tCLP while the INC pin remains in a high state. The wiper does not move during this action and the current wiper setting is stored in EEPROM after tWST. For applications that require a specific wiper setting to be loaded on power-up and never changed, write the desired wiper setting to the EEPROM, then tie CS to VCC. Every time power is cycled to the DS4301, the desired wiper setting is loaded from EEPROM, and since CS is tied to VCC, no changes can be made to the wiper setting. Chip Information TRANSISTOR COUNT: 3512 SUBSTRATE INFO: P-substrate Package Information For the latest package outline information, go to www.maxim-ic.com/DallasPackInfo. EEPROM Characteristics There is a limit to the number of times the EEPROM can be written to before a wear-out occurs (see the Nonvolatile Memory Characteristics table). After EEPROM wear-out occurs, the wiper can still be adjusted, however accurately storing the wiper position is no longer possible. When power is removed from the part, the current wiper position is lost. Upon power-up, the wiper setting stored in EEPROM is loaded within tWLT of VCC reaching a stable voltage level greater than or equal to VCC MIN. If EEPROM wear-out has occurred, the wiper setting that is loaded is unknown. Application Information To achieve the best results when using the DS4301, decouple the power supply with a 0.01µF or 0.1µF capacitor. Use a high-quality ceramic surface-mount capacitor when possible. Surface-mount components minimize lead inductance, improving performace. Ceramic capacitors tend to have adequate highfrequency response for decoupling applications. 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. DS4301 cycled to the device, the wiper setting that was just stored is the setting loaded on power-up.