APPLICATION NOTE A V A I L A B L E AN104 Low Noise, Low Power, 32 Taps X9315 E2POTTM Nonvolatile Digital Potentiometer FEATURES DESCRIPTION • Low Power CMOS —VCC = 2.7V to 5.5V, Single Supply —Active Current, 50µA (Increment) max —Active Current, 400µA (Store) Max —Standby Current, 1µA Max • Low Noise • 31 Resistive Elements —Temperature Compensated —± 20% End to End Resistance Range —VSS to VCC Range • 32 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 • X9315Z = 1KΩ • X9315W = 10KΩ • Packages —8-Lead SOIC —8-Lead MSOP —8-Pin DIP The Xicor X9315 is a solid state "micropower" nonvolatile potentiometer and is ideal for digitally controlled resistance trimming. The X9315 is a resistor array composed of 31 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 X9315 is equal to the maximum resistance value divided by 31. As an example, for the X9315W (10KΩ) each tap point represents 323Ω. All Xicor nonvolatile digital potentiometers are designed and tested for applications requiring extended endurance and data retention. FUNCTIONAL DIAGRAM U/D INC CS CMOS SWITCH 5-BIT UP/DOWN COUNTER 5-BIT NONVOLATILE MEMORY ONE OF THIRTYTWO WIPER POSITION DECODER VH RESISTOR ARRAY STORE AND RECALL CONTROL CIRCUITRY VL VW 6732 FM1 E2POT™ is a trademark of Xicor, Inc. 6732-2.0 5/30/97 T1/C0/D0 SH 1 Characteristics subject to change without notice X9315 PIN DESCRIPTIONS PIN CONFIGURATION VH and VL The high (VH) and low (VL) terminals of the X9315 are equivalent to the fixed terminals of a mechanical potentiometer. The minimum voltage is VSS and the maximum is VCC. 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/MSOP 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 400Ω. INC 1 U/D 2 VH 3 VSS 4 X9315 8 VCC 7 CS 6 VL 5 VW 6732 FM2 PIN NAMES Up/Down (U/D) Symbol 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. 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 X9315 will be placed in the low power standby mode until the device is selected once again. Description VH High Terminal VW Wiper Terminal VL Low Terminal VSS Ground VCC Supply Voltage U/D Up/Down Input INC Increment Input CS Chip Select Input 6732 FM T01 2 X9315 Operation Notes The system may select the X9315, 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 powerup/down cycle recalled the previously stored data. DEVICE OPERATION There are three sections of the X9315: 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 31 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 INC, U/D and CS inputs control the movement of the wiper along the resistor array. With CS set LOW the X9315 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 thirty two 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 X9315 and then move the wiper up and down until the proper trim is attained. SYMBOL TABLE 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. WAVEFORM The value of the counter is stored in nonvolatile memory whenever CS transistions HIGH while the INC input is also HIGH. When the X9315 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. 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 6732 FM 3 3 X9315 ABSOLUTE MAXIMUM RATINGS* *COMMENT Temperature under Bias .........................–65°C to +135°C Storage Temperature..............................–65°C to +150°C Voltage on CS, INC, U/D VH, VL and VCC with Respect to VSS.................................. –1V to +7V ∆V = |VH–VL| ................................................................. 5V Lead Temperature (Soldering 10 seconds)............. 300°C Wiper Current ........................................................... ±1mA 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. ANALOG CHARACTERISTICS Electrical Characteristics Temperature under Bias.........................–65°C to +135°C End-to-End Resistance Tolerance .......................... ±20% Power Rating at 25°C ..............................................10mW Wiper Current ................................................. ±1mA Max. Typical Wiper Resistance ............................ 400Ω at 1mA Typical Noise.................................. < –140dB√ Hz Ref: 1V Temperature Coefficient (–40°C to +85°C) ..............................+300 ppm/°C Typical Ratiometric Temperature Coefficient .................. ±20 ppm Wiper Adjustability Unlimited Wiper Adjustment (Non-Store operation) Wiper Position Store Operations .......................... 100,000 Physical Characteristics Marking Includes Manufacturer’s Trademark Resistance Value or Code Date Code Resolution Resistance ................................................................... 3% Linearity Absolute Linearity(1) ...........................................±1.0 Ml(2) Relative Linearity(3) ...........................................±0.2 Ml(2) Test Circuit #1 Test Circuit #2 VH VH TEST POINT TEST POINT VW VW VL VL FORCE CURRENT 6732 FM 5 6732 FM 4 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/31. (3) Relative Linearity is a measure of the error in step size between taps = V W(n+1) – [Vw(n) + Ml] = +0.2 Ml. 4 X9315 RECOMMENDED OPERATING CONDITIONS Temperature Min. Max. Supply Voltage Limits Commercial 0°C +70°C X9315 5V ±10% Industrial –40°C +85°C X9315-2.7 2.7V to 5.5V 6732 PGM T02 6732 PGM T03 D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.) Limits Symbol Parameter Min. Typ.(4) Max. Units Test Conditions ICC1 VCC Active Current (Increment) 50 µA CS = VIL, U/D = VIL or VIH and INC = 0.4V/2.4V @ max. tCYC ICC2 VCC Active Current (Store) 400 µA CS = VIH, U/D = VIL or VIH and INC = VIH ISB Standby Supply Current 1 µA CS = VCC – 0.3V, U/D and INC = VSS or VCC – 0.3V ILI CS, INC, U/D Input ±10 µA VIN = VSS to VCC 2 VCC + 1 V –0.5 0.8 V 1000 Ω Leakage Current VIH CS, INC, U/D Input HIGH Voltage VIL CS, INC, U/D Input LOW Voltage RW Wiper Resistence VVH VH Terminal Voltage VSS VCC V VVL VL Terminal Voltage VSS VCC V 10 pF CIN(5) 400 CS, INC, U/D Input Max. Wiper Current ±1mA VCC = 5V, VIN = VSS, TA = 25°C, f = 1MHz Capacitance 6732 PGM T04 STANDARD PARTS Part Number Maximum Resistance Wiper Increments Minimum Resistance X9315Z 1KΩ 32.3Ω 100Ω X9315W 10KΩ 323Ω 100Ω 6732 PGM T05 Notes: (4) Typical values are for TA = 25°C and nominal supply voltage. (5) This parameter is periodically sampled and not 100% tested. 5 X9315 A.C. CONDITIONS OF TEST MODE SELECTION 0V to 3V CS Input Rise and Fall Times 10ns L H Wiper Up Input Reference Levels 1.5V L L Wiper Down H X Store Wiper Position X X Standby L X No Store, Return to Standby Input Pulse Levels INC 6732 PGM T06 H U/D Mode 6732 PGM T07 A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified) Limits Symbol Parameter Typ.(6) Min. Max. Units tCl CS to INC Setup 100 tlD INC HIGH to U/D Change 100 ns tDI U/D to INC Setup 2.9 µs tlL INC LOW Period 1 µs tlH INC HIGH Period 1 µs tlC INC Inactive to CS Inactive 1 µs tCPH CS Deselect Time (NO STORE) tIW INC to Vw Change tCYC INC Cycle Time tR, tF(7) tPU(7) tR VCC(7) INC Input Rise and Fall Time tWR Store Cycle ns 100 ns 1 5 µs 500 µs 5 µs 50 mV/µs µs 4 Power up to Wiper Stable VCC Power-up Rate 0.2 5 10 ms 6732 PGM T08 A.C. TIMING CS tCYC tCI tIL tIH tIC tCPH 90% 90% 10% INC tID tDI tF tR U/D tIW VW MI (8) 6732 FM 06 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 V W output due to a change in the wiper position. 6 X9315 TYPICAL NOISE 0 -10 -20 -30 -40 -50 Noise (dB) -60 -70 -80 -90 -100 -110 -120 -130 -140 -150 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 65 85 105 190 200 Frequenc y (KHz) TYPICAL RTOTAL vs. TEMPERATURE 10000 9800 9600 9400 Rtotal 9200 9000 8800 8600 8400 8200 8000 -55 -45 -35 -25 -15 -5 5 15 35 45 25 Temperature 7 55 75 95 115 125 C° X9315 TYPICAL TOTAL RESISTANCE TEMPERATURE COEFFICIENT 0 -50 -100 -150 PPM -200 -250 -300 -350 -55 -45 -35 -25 -15 -5 5 15 25 35 45 Temperature 55 65 75 85 95 24 26 105 115 125 °C TYPICAL WIPER RESISTANCE 800 700 600 Rw (Ohms) 500 400 300 200 100 0 0 2 4 6 8 10 12 14 16 Tap 8 18 20 22 28 30 32 X9315 TYPICAL ABSOLUTE % ERROR PER TAP POSITION 40.0% 30.0% Absolute % Error 20.0% 10.0% 0.0% -10.0% -20.0% -30.0% -40.0% 0 3 6 9 12 15 18 21 24 27 30 18 21 24 27 30 Tap TYPICAL RELATIVE % ERROR PER TAP POSITION 20.0% 15.0% Relative % Error 10.0% 5.0% 0.0% -5.0% -10.0% -15.0% -20.0% 0 3 6 9 12 15 Tap 9 X9315 PACKAGING INFORMATION 8-LEAD MINIATURE SMALL OUTLINE GULL WING PACKAGE TYPE M 0.118 ± 0.002 (3.00 ± 0.05) 0.012 + 0.006 / -0.002 (0.30 + 0.15 / -0.05) 0.0256 (0.65) TYP R 0.014 (0.36) 0.118 ± 0.002 (3.00 ± 0.05) 0.030 (0.76) 0.0216 (0.55) 0.036 (0.91) 0.032 (0.81) 0.040 ± 0.002 (1.02 ± 0.05) 0.007 (0.18) 0.005 (0.13) 7° TYP 0.008 (0.20) 0.004 (0.10) 0.150 (3.81) REF. 0.193 (4.90) REF. NOTE: 1. ALL DIMENSIONS IN INCHES AND (MILLIMETERS) 3003 ILL 01 10 X9315 PACKAGING INFORMATION 8-LEAD PLASTIC DUAL IN-LINE PACKAGE TYPE P 0.430 (10.92) 0.360 (9.14) 0.260 (6.60) 0.240 (6.10) PIN 1 INDEX PIN 1 0.300 (7.62) REF. HALF SHOULDER WIDTH ON ALL END PINS OPTIONAL 0.145 (3.68) 0.128 (3.25) SEATING PLANE 0.025 (0.64) 0.015 (0.38) 0.065 (1.65) 0.045 (1.14) 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: 1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) 2. PACKAGE DIMENSIONS EXCLUDE MOLDING FLASH 11 X9315 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) 12 0.030" TYPICAL 8 PLACES X9315 ORDERING INFORMATION X9315X X X X VCC Limits Blank = 5V ±10% –2.7 = 2.7V to 5.5V Temperature Range Blank = Commercial = 0°C to +70°C I = Industrial = –40°C to +85°C Package M = 8-Lead MSOP P = 8-Lead Plastic DIP S = 8-Lead SOIC End to End Resistance Z = 1KΩ W = 10KΩ 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. 13