APPLICATION NOTES A V A I L A B L E AN42 • AN44–48 • AN50 • AN52 • AN53 • AN71 • AN73 Terminal X9312 Voltage 0V to +15V, 100 Taps X9312 E2POT™ Nonvolatile Digital Potentiometer FEATURES DESCRIPTION • • The Xicor X9312 is a solid state nonvolatile potentiometer and is ideal for digitally controlled resistance trimming. • • • • • • • Compatible with X9C102/103/104/503 Low Power CMOS —Active Current, 3mA Max —Standby Current, 1mA Max 99 Resistive Elements —Temperature Compensated —±20% End to End Resistance Range — 0 to +15V Range 100 Wiper Tap Points —Wiper Positioned via Three-Wire Interface —Similar to TTL Up/Down Counter —Wiper Position Stored in Nonvolatile Memory and Recalled on Power-Up 100 Year Wiper Position Data Retention X9312Z = 1KΩ X9312W = 10KΩ X9312U = 50KΩ X9312T = 100KΩ The X9312 is a resistor array composed of 99 resistive elements. Between each element and at either end are tap points accessible to the wiper element. 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 power-up operation. The resolution of the X9312 is equal to the maximum resistance value divided by 99. As an example, for the X9312U (50KΩ) each tap point represents 505Ω. All Xicor nonvolatile memories are designed and tested for applications requiring extended endurance and data retention. FUNCTIONAL DIAGRAM U/D INC CS 7-BIT UP/DOWN COUNTER 99 VH 98 97 7-BIT NONVOLATILE MEMORY ONE OF ONEHUNDRED DECODER 96 TRANSFER GATES RESISTOR ARRAY 2 VCC GND STORE AND RECALL CONTROL CIRCUITRY 1 0 VL VW 3865 FHD F01 E2POT™ is a trademark of Xicor, Inc. ©Xicor, Inc. 1994, 1995 Patents Pending 3865-2.4 12/1/95 T1/C0/D0 NS 1 Characteristics subject to change without notice X9312 PIN DESCRIPTIONS PIN CONFIGURATION VH and VL The high (VH) and low (VL) terminals of the X9312 are equivalent to the fixed terminals of a mechanical potentiometer. The minimum voltage is 0V and the maximum is +15V. 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. DIP/SOIC INC 1 8 VCC U/D 2 7 CS VH 3 6 VL VSS 4 5 VW VW X9312 3863 FHD F02.1 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 40Ω. PIN NAMES Up/Down (U/D) The U/D input controls the direction of the wiper movement and whether the counter is incremented or decremented. 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. Symbol Description VH VW VL VSS VCC U/D INC CS High Terminal Wiper Terminal Low Terminal Ground Supply Voltage Up/Down Input Increment Input Chip Select Input 3865 PGM T01 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 X9312 will be placed in the low power standby mode until the device is selected once again. 2 X9312 DEVICE OPERATION Operation Notes There are three sections of the X9312: 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. The system may select the X9312, 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-up/down cycle recalled the previously stored data. 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 INC, U/D and CS inputs control the movement of the wiper along the resistor array. With CS set LOW the X9312 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 state of U/D may be changed while CS remains LOW. This allows the host system to enable the X9312 and then move the wiper up and down until the proper trim is attained. TIW/RTOTAL The electronic switches on the X9312 operate in a “make before break” 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 significant amount if the wiper is moved several positions. The wiper, when at either fixed 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 value of the counter is stored in nonvolatile memory whenever CS transistions HIGH while the INC input is also HIGH. RTOTAL with VCC Removed When the X9312 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. The end to end resistance of the array will fluctuate once VCC is removed. SYMBOL TABLE WAVEFORM 3 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 Don’t Care: Changes Allowed N/A Changing: State Not Known Center Line is High Impedance X9312 ABSOLUTE MAXIMUM RATINGS* Temperature under Bias .................. –65°C to +135°C Storage Temperature ....................... –65°C to +150°C Voltage on CS, INC, U/D and VCC with Respect to VSS ............................... –1V to +7V Voltage on VH and VL Referenced to VSS ∆V = |VH–VL| X9312Z, X9312W, X9312U, and X9312T ....... 15V Lead Temperature (Soldering 10 seconds) ....... 300°C Wiper Current ..................................................... ±1mA *COMMENT Stresses above those listed under “Absolute Maximum Ratings” 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 specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ANALOG CHARACTERISTICS Electrical Characteristics Temperature Coefficient End-to-End Resistance Tolerance ..................... ±20% Power Rating at 25°C X9312Z, .................................................... 225mW X9312W, X9312U, and X9312T ................. 25mW Wiper Current ............................................ ±1mA Max. Typical Wiper Resistance ......................... 40Ω at 1mA Typical Noise .......................... < –120dB/ Hz Ref: 1V (–40°C to +85°C) X9312W, X9312U and X9312T ....................................... +300 ppm/°C Typical Ratiometric Temperature Coefficient ............ ±20 ppm Wiper Adjustability Unlimited Wiper Adjustment (Non-Store operation) Wiper Position Store Operations ............... 10,000 Data Changes Resolution Resistance ............................................................. 1% Physical Characteristics Linearity Absolute Linearity(1) ........................................ ±1.0 Ml(2) Relative Linearity(3) ..................................... ±0.2 Ml(2) Marking Includes Manufacturer’s Trademark Resistance Value or Code Date Code Test Circuit #1 Test Circuit #2 VH VH TEST POINT TEST POINT VW VW VL VL FORCE CURRENT 3865 FHD F04 3865 FHD F05 Notes: (1) Absolute Linearity is utilized to determine actual wiper voltage versus expected voltage = (Vw(n)(actual) – Vw(n)(expected)) = ±1 Ml Maximum. (2) 1 Ml = Minimum Increment = RTOT/99. (3) Relative Linearity is a measure of the error in step size between taps = VW(n+1) – [Vw(n) + Ml] = +0.2 Ml. 4 X9312 RECOMMENDED OPERATING CONDITIONS Temperature Min. Max. Supply Voltage Limits Commercial Industrial Military 0°C –40°C –55°C +70°C +85°C +125°C X9312 5V ±10% 3865 PGM T04.1 3865 PGM T03.1 D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.) Limits Symbol Parameter ICC VCC Active Current ISB Standby Supply Current ILI CS, INC, U/D Input Leakage Current CS, INC, U/D Input HIGH Voltage CS, INC, U/D Input LOW Voltage Wiper Resistence VH Terminal Voltage VL Terminal Voltage CS, INC, U/D Input Capacitance VIH VIL RW VVH VVL CIN(5) Typ.(4) Max. Units 1 3 mA 500 1000 µA ±10 µA 2 VCC + 1 V –1 0.8 V 100 15 15 10 Ω V V pF Min. 40 0 0 Test Conditions CS = VIL, U/D = VIL or VIH and INC = 0.4V/2.4V @ max. tCYC CS = VCC – 0.3V, U/D and INC = VSS or VCC – 0.3V VIN = VSS to VCC Max. Wiper Current ±1mA VCC = 5V, VIN = VSS, TA = 25°C, f = 1MHz 3865 PGM T05.3 STANDARD PARTS Part Number Maximum Resistance Wiper Increments Minimum Resistance X9312Z X9312W X9312U X9312T 1KΩ 10KΩ 50KΩ 100KΩ 10.1Ω 101Ω 505Ω 1010Ω 40Ω 40Ω 40Ω 40Ω Notes: (4) Typical values are for TA = 25°C and nominal supply voltage. (5) This parameter is periodically sampled and not 100% tested. 5 3865 PGM T08.1 X9312 A.C. CONDITIONS OF TEST MODE SELECTION Input Pulse Levels Input Rise and Fall Times Input Reference Levels CS 0V to 3V 10ns 1.5V INC U/D Mode H X L H L X X X Wiper Up Wiper Down Store Wiper Position Standby No Store, Return to Standby L L 3865 PGM T05.1 H 3865 PGM T06 A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified) Limits Symbol Parameter Min. tCl tlD tDI tlL tlH tlC tCPH tIW tCYC tR, tF(7) tPU(7) tR VCC(7) CS to INC Setup INC HIGH to U/D Change U/D to INC Setup INC LOW Period INC HIGH Period INC Inactive to CS Inactive CS Deselect Time INC to Vw Change INC Cycle Time INC Input Rise and Fall Time Power up to Wiper Stable VCC Power-up Rate 100 100 1 1 1 1 20 Typ.(6) 100 Max. 500 4 500 500 50 0.2 Units ns ns µs µs µs µs ms µs µs µs µs mV/µs 3865 PGM T07.4 A.C. Timing CS tCYC tCI tIL tIH tIC tCPH 90% 90% 10% INC tID tDI tF tR U/D tIW VW MI (8) 3865 FHD F03 Notes: (6) Typical values are for TA = 25°C and nominal supply voltage. (7) This parameter is periodically sampled and not 100% tested. (8) MI in the A.C. timing diagram refers to the minimum incremental change in the VW output due to a change in the wiper position. 6 X9312 PACKAGING INFORMATION 8-LEAD PLASTIC DUAL IN-LINE PACKAGE TYPE P 0.430 (10.92) 0.360 (9.14) 0.092 (2.34) DIA. NOM. 0.255 (6.47) 0.245 (6.22) PIN 1 INDEX PIN 1 0.300 (7.62) REF. HALF SHOULDER WIDTH ON ALL END PINS OPTIONAL 0.140 (3.56) 0.130 (3.30) SEATING PLANE 0.020 (0.51) 0.015 (0.38) 0.062 (1.57) 0.058 (1.47) 0.150 (3.81) 0.125 (3.18) 0.020 (0.51) 0.016 (0.41) 0.110 (2.79) 0.090 (2.29) 0.015 (0.38) MAX. 0.060 (1.52) 0.020 (0.51) 0.325 (8.25) 0.300 (7.62) 0° 15° TYP. 0.010 (0.25) NOTE: ALLALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) NOTE: DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) 3926 FHD F01 7 X9312 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) X 45° 0.020 (0.50) 0° – 8° 0.0075 (0.19) 0.010 (0.25) 0.027 (0.683) 0.037 (0.937) NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESIS IN MILLIMETERS) 3926 FHD F22 8 X9312 ORDERING INFORMATION X9312X X X Temperature Range Blank = Commercial = 0°C to +70°C I = Industrial = –40°C to +85°C M = Military = –55°C to +125°C Package P = 8-Lead Plastic DIP S = 8-Lead SOIC End to End Resistance Z = 1KΩ W = 10KΩ U = 50KΩ T = 100KΩ LIMITED WARRANTY Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification 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 fitness for any purpose. Xicor, Inc. reserves the right to discontinue production and change specifications 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. Xicor's 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 significant 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. 9