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Details, datasheet, quote on part number:X9315
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| Part: | X9315 |
| Category: | Analog & Mixed-Signal Processing => Potentiometers |
| Description: | Single 32 Tap Xdcp, Low Power Increment/decrement Interface Single Supply |
| Company: | Fairchild Semiconductor |
| Datasheet: | Download X9315 datasheet File size : 378 kB |
| Request For quote: | Find where to buy X9315
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Datasheet text preview:
APPLICATION NOTE AVAILABLE
AN20 · AN4253 · AN71 · AN73 · AN88 · AN9192 · AN99 · AN115 · AN120 · AN124 · AN133 · AN134 · AN135
Low Noise, Low Power, 32 Taps
X9315
Digitally Controlled Potentiometer (XDCPTM)
FEATURES · Solid-state potentiometer · 3-wire serial interface · 32 wiper tap points -- Wiper position stored in nonvolatile memory and recalled on power-up · 31 resistive elements -- Temperature compensated -- End to end resistance range ± 20% --Terminal voltage, 0 to VCC · Low power CMOS -- VCC = 2.7V or 5V -- Active current, 50/400µA max. -- Standby current, 1µA max. · High reliability -- Endurance, 100,000 data changes per bit -- Register data retention, 100 years · RTOTAL values = 10K, 50K, 100K · Packages -- 8-lead SOIC, MSOP and DIP DESCRIPTION The Xicor X9315 is a digitally controlled potentiometer (XDCP). The device consists of a resistor array, wiper switches, a control section, and nonvolatile memory. The wiper position is controlled by a 3-wire interface. The potentiometer is implemented by a resistor array composed of 31 resistive elements and a wiper switching network. 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 power-up operation. The device can be used as a three-terminal potentiometer or as a two-terminal variable resistor in a wide variety of applications including: control parameter adjustments signal processing BLOCK DIAGRAM
U/D INC CS RH/VH Control and Memory RW/VW 5-Bit Nonvolatile Memory 5-Bit Up/Down Counter RH/VH
VCC (Supply Voltage)
31 30 29 28 One of Thirty Two Decoder 2
Up/Down (U/D) Increment (INC) Device Select (CS)
Transfer Gates
Resistor Array
RL/VL Store and Recall Control Circuitry
VSS (Ground) General
VCC VSS
1 0 RL/VL RW/VW Detailed
XDCPTM is a trademark of Xicor, Inc. REV 1.3.2 1/14/03
www.xicor.com
Characteristics subject to change without notice.
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X9315
PIN DESCRIPTIONS RH/VH and RL/VL The high (RH/VH) and low (RL/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. The terminology of RL/ VL and RH/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. RW/VW RW/Vw is the wiper terminal and is 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 200 at VCC = 5V. 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. 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. PIN CONFIGURATION
DIP/SOIC/MSOP INC U/D RH/VH VSS 1 2 3 4 X9315 8 7 6 5 VCC CS RL/VL RW/VW
PIN NAMES Symbol
RH/VH RW/VW RL/VL VSS VCC U/D INC CS
Description
High terminal Wiper terminal Low terminal Ground Supply voltage Up/Down control input Increment control input Chip Select control input
PRINCIPLES OF 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 connection at that point to the wiper. 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 electronic switches on the device 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. When the device is powered-down, the last wiper position stored will be maintained in the nonvolatile memory. When power is restored, the contents of the memory are recalled and the wiper is set to the value last stored.
REV 1.3.2 1/14/03
www.xicor.com
Characteristics subject to change without notice.
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X9315
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 five bit counter. The output of this counter is decoded to select one of thirty two wiper positions along the resistive array. The value of the counter is stored in nonvolatile memory whenever CS transitions HIGH while the INC input is also HIGH. The system may select the X9315, move the wiper and deselect the device without having to store the latest wiper position in nonvolatile memory. After the wiper movement is performed as described above and once the new position is reached, the system must keep INC LOW while taking CS HIGH. The new wiper position will be maintained until changed by the system or until a power-up/down cycle recalled the previously stored data. This procedure allows 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 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. MODE SELECTION CS
L L H H X L
INC
U/D
H L X X X Wiper Up
Mode
Wiper Down Store Wiper Position Standby Current No Store, Return to Standby
SYMBOL TABLE
WAVEFORM
INPUTS Must be steady May change from Low to High May change from High to Low Don't Care: Changes Allowed N/A
OUTPUTS Will be steady Will change from Low to High Will change from High to Low Changing: State Not Known Center Line is High Impedance
REV 1.3.2 1/14/03
www.xicor.com
Characteristics subject to change without notice.
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