APPLICATION NOTE A V A I L A B L E AN42 AN4448 AN50 AN52 AN53 AN71 AN92 Terminal Voltage 5V, 100 Taps, Log Taper X9C303 Digitally Controlled (XDCP) Potentiometer FEATURES DESCRIPTION Solid-State Potentiometer Three-Wire Serial Interface 100 Wiper Tap Points NWiper Position Stored in Nonvolatile Memory and Recalled on Power-up 99 Resistive Elements, Log Taper NTemperature Compensated NEnd to End Resistance, 15% NTerminal Voltages, 5V Low Power CMOS NVCC = 5V NActive Current, 3mA Max. NStandby Current, 500A Max. High Reliability NEndurance, 100,000 Data Changes per Bit NRegister Data Retention, 100 Years X9C303, 32 k Packages N8 Lead TSSOP N8 Lead SOIC N8 Pin DIP The Xicor X9C303 is a digitally-controlled (DCP) potentiometer. The device consists of a resistor array, wiper switches, a control section, and nonvolatile memory. The wiper position is controlled by a three-wire interface. The resistor array is composed of 99 resistive elements. Between each element and at either end are tap points accessible to the wiper terminal. The position of the wiper element is controlled by the CS, U/D, and INC inputs. The position of the wiper can be stored in nonvolatile memory and then be recalled upon a subsequent powerup operation. The device can be used as a three-terminal potentiometer or as a two-terminal variable resistor in a wide variety of applications ranging from control, to signal processing, to parameter adjustment. Digitally-controlled potentiometers provide three powerful application advantages; (1) the variability and reliability of a solidstate potentiometer, (2) the exibility of computer-based digital controls, and (3) the use of nonvolatile memory for potentiometer settings retention. FUNCTIONAL DIAGRAM U/D INC CS 7-BIT UP/DOWN COUNTER 99 R H/VH 98 97 7-BIT NONVOLATILE MEMORY ONE 96 OF ONEHUNDRED DECODER TRANSFER GATES RESISTOR ARRAY 2 VCC VSS STORE AND RECALL CONTROL CIRCUITRY 1 0 R L/VL R W/VW XDCP is a trademark of Xicor, Inc. 9900-2000.1 3/31/99 # Characteristics subject to change without notice X9C303 PIN NAMES PIN DESCRIPTIONS VH and VL The high (VH) and low (VL) terminals of the device are equivalent to the xed terminals of a mechanical potentiometer. The minimum voltage is 5V and the maximum is +5V. It should be noted that the terminology of VL and VH references the relative position of the terminal in relation to wiper movement direction selected by the U/D input and not the voltage potential on the terminal. Symbol VW VW is the wiper terminal, equivalent to the movable terminal of a mechanical potentiometer. The position of the wiper within the array is determined by the control inputs. The wiper terminal series resistance is typically 40. Up/Down (U/D) The U/D input controls the direction of the wiper movement and whether the counter is incremented or decremented. Description VH High Terminal (Potentiometer) VW Wiper Terminal (Potentiometer) VL Low Terminal (Potentiometer) VSS Ground VCC Supply Voltage U/D Up/Down Control Input INC Increment Control Input CS Chip Select Control Input NC No Connection POTENTIOMETER RELATIONSHIPS S100 VH (VS) Increment (INC) The INC input is negative-edge triggered. Toggling INC will move the wiper and either increment or decrement the counter in the direction indicated by the logic level on the U/D input. R99 S99 R98 S98 VW Chip Select (CS) The device is selected when the CS input is LOW. The current counter value is stored in nonvolatile memory when CS is returned HIGH while the INC input is also HIGH. After the store operation is complete the device will be placed in the low power standby mode until the device is selected once again. S3 R2 S2 R1 S1 VL PIN CONFIGURATION R1 + R2 + . . . + Ri VW G i = 20Log ------------------------------------------------- = --------- ( V L = 0V ) R TOTAL VS R 1 + R 2 + . . . + R 99 @ 33K = R TOTAL DIP/SOIC/(TSSOP) (CS) INC 1 (VCC) U/D 2 (INC) 3 VH (U/D) VSS 4 X9C303 8 VCC (VL) 7 CS (VW) 6 VL 5 VW (VH) (Refer Test Circuit 1) (VSS) # Running H/F 1 The system may select the X9C303, move the wiper, and deselect the device without having to store the latest wiper position in nonvolatile memory. The wiper movement is performed as described above; once the new position is reached, the system would the keep INC LOW while taking CS HIGH. The new wiper position would be maintained until changed by the system or until a power-down/up cycle recalled the previously stored data. PRINCIPLES OF OPERATION There are three sections of the X9C303: the input control, counter and decode section; the nonvolatile memory; and the resistor array. The input control section operates just like an up/down counter. The output of this counter is decoded to turn on a single electronic switch connecting a point on the resistor array to the wiper output. Under the proper conditions the contents of the counter can be stored in nonvolatile memory and retained for future use. The resistor array is comprised of 99 individual resistors connected in series. At either end of the array and between each resistor is an electronic switch that transfers the potential at that point to the wiper. This would allow the system to always power-up to a preset value stored in nonvolatile memory; then during system operation minor adjustments could be made. The adjustments might be based on user preference: system parameter changes due to temperature drift, etc... The wiper, when at either xed terminal, acts like its mechanical equivalent and does not move beyond the last position. That is, the counter does not wrap around when clocked to either extreme. The state of U/D may be changed while CS remains LOW. This allows the host system to enable the device and then move the wiper up and down until the proper trim is attained. The electronic switches on the device operate in a Omake before breakO mode when the wiper changes tap positions. If the wiper is moved several positions, multiple taps are connected to the wiper for tIW (INC to VW change). The RTOTAL value for the device can temporarily be reduced by a signicant amount if the wiper is moved several positions. MODE SELECTION CS U/D Mode L H Wiper Up L L Wiper Down H X Store Wiper Position X X Standby Current L X No Store, Return to Standby H When the device is powered-down, the last counter position stored will be maintained in the nonvolatile memory. When power is restored, the contents of the memory are recalled and the counter is reset to the value last stored. INC SYMBOL TABLE WAVEFORM Instructions and Programming The INC, U/D and CS inputs control the movement of the wiper along the resistor array. With CS set LOW the device is selected and enabled to respond to the U/D and INC inputs. HIGH to LOW transitions on INC will increment or decrement (depending on the state of the U/D input) a seven-bit counter. The output of this counter is decoded to select one of one-hundred wiper positions along the resistive array. The value of the counter is stored in nonvolatile memory whenever CS transistions HIGH while the INC input is also HIGH. # INPUTS OUTPUTS Must be steady Will be steady May change from Low to High Will change from Low to High May change from High to Low Will change from High to Low DonOt Care: Changes Allowed N/A Changing: State Not Known Center Line is High Impedance X9C303 ABSOLUTE MAXIMUM RATINGS* *COMMENT Temperature under Bias.........................65C to +135C Storage Temperature..............................65C to +150C Voltage on CS, INC, U/D and VCC with Respect to VSS...................................... 1V to +7V Voltage on VH and VL Referenced to VSS........................................ 8V to +8V V = |VHVL| X9C303 .................................................................... 10V Lead Temperature (Soldering, 10 seconds) ......... +300C Wiper Current ...........................................................1mA Stresses above those listed under OAbsolute Maximum RatingsO may cause permanent damage to the device. This is a stress rating only and the functional operation of the device at these or any other conditions above those listed in the operational sections of this specication is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ANALOG CHARACTERISTICS Temperature Coefficient (40C to +85C) X9C303 ........................................... 400 ppm/C Typical Ratiometric Temperature Coefcient ..................20 ppm Electrical Characteristics End-to-End Resistance Tolerance .......................... 15% Power Rating at 25C X9C303 ................................................................10mW Wiper Current ..................................................1mA Max. Typical Wiper Resistance ..............................40 at 1mA Typical Resistor Noise ............23 nV (RMS)/OHz at 1 KHz Typical Charge Pump Noise.....20 mV (RMS) @ 2.5 MHz Wiper Adjustability Unlimited Wiper Adjustment (Non-Store operation) Wiper Position Store Operations.........................100,000 Data Changes per Bit Relative Variation Relative variation is a measure of the error in step size between taps = log(Vw(n)) log(Vw(n-1)) = 0.0450.003 for tap n = 2 99 Physical Characteristics Marking Includes ManufacturerOs Trademark Resistance Value or Code Date Code Typical Electrical Taper 100.0% 90.0% 80.0% % Total Resistance 70.0% 60.0% 50.0% 40.0% 30.0% 20.0% 10.0% Tap # 99 96 93 90 87 84 81 78 75 72 69 66 63 60 57 54 51 48 45 42 39 36 33 30 27 24 21 18 15 9 6 12 R(VH-VW) R(VW-VL) 3 0 0.0% X9C303 Test Circuit #1 Test Circuit #2 Circuit #3 SPICE Macromodel RTOTAL VH VH RH TEST POINT VS TEST POINT VW VW VL VL FORCE CURRENT CH CW 10pF 25pF CL RL 10pF RW RECOMMENDED OPERATING CONDITIONS Temperature Min. Max. Supply Voltage Limits 0C +70C X9C303 5V 10% Industrial 40C +85C Military 55C +125C Commercial D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.) Limits Parameter Symbol ICC Min. Typ.(1) Max. Units 1 3 mA VCC Active Current Test Conditions CS = VIL, U/D = VIL or VIH and INC = 0.4V to 2.4V @ max. tCYC ISB Standby Supply Current ILI CS, INC, U/D Input Leakage Current VIH CS, INC, U/D Input HIGH Voltage VIL CS, INC, U/D Input LOW Voltage RW Wiper Resistance VH VH Terminal Voltage VL VL Terminal Voltage CIN(2) CS, INC, U/D Input Capacitance CH/CL/ CW Potentiometer Capacitance 200 500 A CS = VCC 0.3V, U/D and INC = VSS or VCC 0.3V 10 A VIN = VSS to VCC 2 VCC + 1 V 1 0.8 V 100 5 +5 V 5 +5 V 10 pF VCC = 5V, VIN = VSS, TA = 25C, f = 1MHz pF See Circuit 3 40 10/10/25 Max. Wiper Current 1mA STANDARD PARTS Part Number Maximum Resistance Wiper Increments Minimum Resistance X9C303 32K Log Taper 40 Typical # Running H/F 1 Notes: (1) Typical values are for TA = 25C and nominal supply voltage. (2) This parameter is periodically sampled and not 100% tested. # Running H/F 1 A.C. CONDITIONS OF TEST Input Pulse Levels 0V to 3V Input Rise and Fall Times 10ns Input Reference Levels 1.5V A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified) Limits Symbol Parameter Typ.(3) Min. Max. Units tCl CS to INC Setup 100 ns tlD INC HIGH to U/D Change 100 ns tDI U/D to INC Setup 2.9 s tlL INC LOW Period 1 s tlH INC HIGH Period 1 s tlC INC Inactive to CS Inactive 1 s tCPH CS Deselect Time 20 ms tIW INC to VW Change tCYC INC Cycle Time tR, tF(4) INC Input Rise and Fall Time 500 ns tPU(4) Power up to Wiper Stable 500 s tR VCC(4) VCC Power-up Rate 50 mV/s 100 500 s 4 s 0.2 A.C. TIMING CS tCYC tCI tIL tIH tIC tCPH 90% 90% 10% INC tID tDI tF U/D tIW VW MI (8) Notes: (3) Typical values are for TA = 25C and nominal supply voltage. # tR Running H/F 1 PACKAGING INFORMATION 8-LEAD PLASTIC SMALL OUTLINE GULL WING PACKAGE TYPE S 0.150 (3.80) 0.158 (4.00) 0.228 (5.80) 0.244 (6.20) PIN 1 INDEX PIN 1 0.014 (0.35) 0.019 (0.49) 0.188 (4.78) 0.197 (5.00) (4X) 7 0.053 (1.35) 0.069 (1.75) 0.004 (0.19) 0.010 (0.25) 0.050 (1.27) 0.010 (0.25) 0.020 (0.50) X 45 0.050" TYPICAL 0.050" TYPICAL 0 8 0.0075 (0.19) 0.010 (0.25) 0.250" 0.016 (0.410) 0.037 (0.937) FOOTPRINT NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) # 0.030" TYPICAL 8 PLACES Running H/F 1 PACKAGING INFORMATION 8-LEAD PLASTIC, TSSOP, PACKAGE TYPE V .025 (.65) BSC .169 (4.3) .252 (6.4) BSC .177 (4.5) .114 (2.9) .122 (3.1) .047 (1.20) .0075 (.19) .0118 (.30) .002 (.05) .006 (.15) .010 (.25) Gage Plane 0 8 Seating Plane .019 (.50) .029 (.75) (4.16) (7.72) Detail A (20X) (1.78) .031 (.80) .041 (1.05) (0.42) (0.65) ALL MEASUREMENTS ARE TYPICAL See Detail OAO NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) # Running H/F 1 ORDERING INFORMATION X9C303 X X Temperature Range Blank = Commercial = 0C to +70C I = Industrial = 40C to +85C Package P = 8-Lead Plastic DIP S8 = 8-Lead SOIC V8 = 8-Lead TSSOP LIMITED WARRANTY Devices sold by Xicor, Inc. are covered by the warranty and patent indemnication provisions appearing in its Terms of Sale only. Xicor, Inc. makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Xicor, Inc. makes no warranty of merchantability or tness for any purpose. Xicor, Inc. reserves the right to discontinue production and change specications and prices at any time and without notice. Xicor, Inc. assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xicor, Inc. product. No other circuits, patents, licenses are implied. U.S. PATENTS Xicor products are covered by one or more of the following U.S. Patents: 4,263,664; 4,274,012; 4,300,212; 4,314,265; 4,326,134; 4,393,481; 4,404,475; 4,450,402; 4,486,769; 4,488,060; 4,520,461; 4,533,846; 4,599,706; 4,617,652; 4,668,932; 4,752,912; 4,829, 482; 4,874, 967; 4,883, 976. Foreign patents and additional patents pending. LIFE RELATED POLICY In situations where semiconductor component failure may endanger life, system designers using this product should design the system with appropriate error detection and correction, redundancy and back-up features to prevent such an occurence. XicorOs products are not authorized for use in critical components in life support devices or systems. 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a signicant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. #