DS1804 DS1804 NV Trimmer Potentiometer FEATURES PIN ASSIGNMENT * Single 100-Position Linear Taper Potentiometer * Nonvolatile "On-Demand" Wiper Storage * Operates from 3V or 5V supplies * Up/Down, Increment Controlled Interface INC 1 8 VCC U/D 2 7 CS H 3 6 L GND 4 5 W 8-PIN DIP (300 MIL) 8-PIN SOIC (150 MIL) * Resistance Values: 10K, 50K, and 100K See Mech. Drawings Section * Available in 8-Pin (300 Mil) DIP, 8-Pin (150 Mil) SOIC packages * Operating Temperature: - Industrial: -40C to 85C PIN DESCRIPTION H L W VCC CS U/D INC GND - - - - - - - High-End of Resistor Low-End of Resistor Wiper Terminal 3V or 5V Power Supply Input Chip Select Up/Down Control Input Increment/Decrement Counter Input - Ground DESCRIPTION The DS1804 is a nonvolatile digital potentiometer having 100 positions. The device provides an ideal method for low-cost trimming applications using a CPU or manual control input with minimal external circuitry. Wiper position of the DS1804 can be stored in EEPROM memory on demand. The device's wiper position is manipulated by a 3-terminal port that provides an increment/decrement counter controlled interface. This port consists of the control inputs CS, INC, and U/D. The DS1804 is available in three resistor grades which include a 10K, 50K, and 100K. The device is provided in an industrial temperature grade. Additionally, the DS1804 will operate from 3V or 5V supplies and is ideal for portable application requirements. Two packaging options are available and include the 8-pin (300 mil) DIP and 8-Pin (150 mil) SOIC. 121797 1/6 DS1804 OPERATION The DS1804 is a single nonvolatile potentiometer. The device has a total of 100 tap-points including the L- and H- terminals. A total of 99 resistive segments exist between the L- and H- terminals. These tap-points are accessible to the W-terminal whose position is controlled via a 3-terminal control port. A block diagram of the DS1804 is shown in Figure 1. The 3-terminal port of the DS1804 provides an increment/decrement interface which is activated via a chip select input. This interface consists of the input signals CS, INC, and U/D. These input signals control a 7-bit up/down counter. The output of the 7-bit up/down counter controls a 1 of 100 decoder to select wiper position. Additionally, this interface provides for a wiper storage operation using the CS and INC input control pins. The timing diagram for the 3-terminal interface control is shown in Figure 2. PIN DESCRIPTIONS VCC - Power Supply Terminal. The DS1804 will support supply voltages ranging from +2.7 to +5.5 volts. GND - Ground Terminal. H - High-end of Resistor. This is the high-end terminal of the potentiometer. It is not required that this terminal be connected to a potential greater than the L-terminal. Voltage applied to the H-terminal can not exceed the power-supply voltage, VCC, or go below ground. L - Low-end of Resistor -This is the low-end terminal of the potentiometer. It is not required that this terminal be connected to a potential less than the H-terminal. Voltage applied to the L-terminal cannot exceed the power-supply voltage, VCC, or go below ground. W - Wiper of the Potentiometer. This pin is the wiper terminal of the potentiometer. Its position on the resistor array is controlled by the 3-terminal control port. Voltage applied to the W-terminal cannot exceed the power-supply voltage, VCC, or go below ground. CS - Chip Select. The CS input is used to activate the control port of the DS1804. This input is active low. When in a high-state, activity on the INC and U/D port pins will not affect or change wiper position. INC - Wiper Movement Control. This input provides for wiper position changes when the CS pin is low. Wiper position changes of the W-terminal will occur one position per high-to-low transition of this input signal. Position changes will not occur if the CS pin is in a high- state. U/D - Up/Down Control. This input sets the direction of wiper movement. When in a high-state and CS is low, any high-to-low transition on INC will cause a one position movement of the wiper towards the H-terminal. When in a low-state and CS is low, any high-to-low transitions on INC will cause the position of the wiper to move towards the L-terminal. DS1804 BLOCK DIAGRAM Figure 1 CS INC CONTROL LOGIC UNIT H 100-TO-1 MULTIPLEXER U/D 3-TERMINAL CONTROL PORT VCC GND POS 99 POS 0 NV MEMORY L W 121797 2/6 DS1804 POWER-UP/POWER-DOWN CONDITIONS On power-up the DS1804 will load the value of EEPROM memory into the wiper position register (or 1 of 100 decoder). The value of this register can then be set to another wiper position if desired, by using the 3-terminal control port. On power-up, wiper position will be loaded within a maximum time period of 500 s once the power-supply is stable. Additionally, the 3- terminal interface port will be active after 50 ms. On power-down, the wiper position register data will be lost. On the next device power-up, the value of EEPROM memory will be loaded into the wiper position register. On shipment from the factory, Dallas Semiconductor does not guarantee a specified EEPROM memory value. This value should be set by the customer as needed. The next section discusses wiper storage operation for the DS1804. high while the INC is high. Once this condition has occurred the value of the current wiper position will be written to EEPROM memory. The DS1804 is specified to accept 50,000 writes to EEPROM before a wear-out condition. After wear out the DS1804 will still function and wiper position can be changed during powered conditions using the 3-terminal control port. However, on power-up the wiper-position will be indeterminate. ONE TIME PROGRAMMABILITY (OTP) The DS1804 can be easily used as an OTP device. The user of the DS1804 can trim the desired value of the wiper position and set this position for storage as described above. Any activity through the 3-terminal port can then be prevented by connecting the CS input pin to VCC. Also, an OTP application does not adversely affect the number of times EEPROM is written, since EEPROM will only be loaded and not written during a power-up or power-down condition. NONVOLATILE WIPER STORAGE Wiper position of the DS1804 can be stored using the INC and CS inputs. Storage of the wiper position takes place, whenever the CS input transitions from low-to- On power-up the DS1804 will load the current value of EEPROM memory into the wiper position register. 121797 3/6 DS1804 ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature -1.0V to +7.0V -40C to +85C; industrial -55C to +125C 260C for 10 seconds * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. RECOMMENDED DC OPERATING CONDITIONS PARAMETER SYMBOL MIN Supply Voltage VCC Input Logic 1 Input Logic 0 Resistor Inputs (-40C to +85C) TYP MAX UNITS NOTES +2.7 5.5 V 1 VIH 2.0 VCC+0.5 V 1, 2 VIL -0.5 +0.8 +0.6 V 1, 15 L, H, W GND-0.5 VCC+0.5 V 1, 3 DC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL Supply Current ICC Input Leakage ILI Wiper Resistance RW Wiper Current IW (-40C to +85C; VCC=2.7V to 5.5V) MIN TYP -1 400 MAX UNITS NOTES 400 A 4 +1 A 1000 1 mA 40 A A Standby Current 3 Volts 5 Volts ISTBY Wiper Load Time tWLT 500 s 6 Power-Up Time tPU 50 ms 14 10 20 ANALOG RESISTOR CHARACTERISTICS PARAMETER SYMBOL (-40C to +85C; VCC=2.7V to 5.5V) MIN Total Resistance TYP MAX 10 50 100 End-to-End Resistor Tolerance 5 -20 +20 UNITS NOTES K 7 % 8 Absolute Linearity 0.6 LSB 9 Relative Linearity 0.25 LSB 10 MHz 11 -3 dB Cutoff Frequency Temperature Coefficient 121797 4/6 fcutoff 650 ppm/C DS1804 CAPACITANCE PARAMETER Input Capacitance Output Capacitance (25C; VCC=2.7V to 5.5V) SYMBOL MIN TYP MAX UNITS NOTES CIN 5 pF 12 COUT 7 pF 12 AC ELECTRICAL CHARACTERISTICS PARAMETER (-40C to +85C; VCC=2.7V to 5.5V) SYMBOL MIN CS to INC Setup tCI U/D to INC Setup UNITS NOTES 50 ns 13 tDI 100 ns 13 INC Low Period tIL 50 ns 13 INC High Period tIH 100 ns 13 INC Inactive to CS Inactive tIC 500 ns 13 tCPH 100 ns 13 CS Deselect Time Wiper Change to INC Low TYP MAX tIW 200 ns 13 INC Rise and Fall Times tR, tF 500 s 13 INC Low to CS Inactive tIK ns 16 ms 13, 17 Wiper Storage Time tWST 50 10 NOTES: 1. All voltages are referenced to ground. 2. Valid for VCC = 5V only. 3. Resistor input voltages cannot go below ground or exceed VCC by the amounts as shown in the table. 4. Maximum current specifications are based on the clock rate of INC input. This specification represents the current required when changing the wiper position. 5. Standby current levels apply when all inputs are driven to appropriate supply levels. CS, INC, U/D = VCC. 6. Wiper load time is specified as the time required for the DS1804 to load the wiper position with the contents of nonvolatile memory once VCC has reached a stable operating voltage equal to or greater than 2.7V. 7. The DS1804 is available in three resistor values. These include the DS1804-010; 10K , the DS1804-050 50K; and the DS1804-100 100K. 8. The end-to-end resistance tolerance of the DS1804 can be expected to shift with temperature. However, this change will not exceed 20% of the nominal resistor value of the part. 9. Absolute linearity is used to compare measured wiper voltage versus expected wiper voltage as determined by wiper position. The DS1804 is specified to provide an absolute linearity of 0.60 LSB 10. Relative linearity is used to determined the change in voltage between successive tap positions. The DS1804 is specified to provide a relative linearity specification of 0.25 LSB. 11. -3 dB cutoff frequency characteristics for the DS1804 depend on potentiometer total resistance. DS1804-010, 1 MHz, DS1804-050; 200 KHz, and DS1804-100; 100 KHz. 121797 5/6 DS1804 12. Capacitance values apply at 25C. 13. See Figure 2. 14. Power-up time is specified as the time required before the 3-terminal control becomes active after a stable power supply level has been reached. 15. At VCC = 2.7V, VIL = 0.8V 16. The INC low to CS inactive is specified to be 50 ns minimum. This is the transition condition which allows the DS1804 3-terminal port to become inactive without writing the EEPROM memory of the part. 17. Wiper Storage Time, tWST, is the time require for the DS1804 to write EEPROM memory for storage of a new wiper position. The maximum time required to accomplish this task is specified at 10 ms. DS1804 ORDERING INFORMATION ORDERING NUMBER PACKAGE OPERATING TEMP. VERSION DS1804-010 8L DIP -40C TO +85C 10K DS1804-050 8L DIP -40C TO +85C 50K DS1804-100 8L DIP -40C TO +85C 100K DS1804Z-010 8L SOIC (150 MIL) -40C TO +85C 10K DS1804Z-050 8L SOIC (150 MIL) -40C TO +85C 50K DS1804Z-100 8L SOIC (150 MIL) -40C TO +85C 100K 3-TERMINAL INTERFACE TIMING DIAGRAM Figure 2 WIPER STORAGE CONDITION WIPER NON-STORAGE CONDITION CS tCPH tCI INC tIH tIC tF tIL tDI tR U/D tIW VW 121797 6/6 tWPS tIK