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Xicor |
APPLICATION NOTE
A V A I LABLE
AN104
Low Noise, Low Power, 32 Taps
X9315
E2POTTM Nonvolatile Digital Potentiometer
FEATURES
• 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
FUNCTIONAL DIAGRAM
DESCRIPTION
The Xicor X9315 is a solid state "micropower" nonvol-
atile 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 posi-
tion 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 sub-
sequent 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 de-
signed and tested for applications requiring extended
endurance and data retention.
U/D 5-BIT
INC UP/DOWN
CS COUNTER
CMOS SWITCH
VH
5-BIT
NONVOLATILE
MEMORY
STORE AND
RECALL
CONTROL
CIRCUITRY
ONE
OF
THIRTY-
TWO
WIPER
POSITION
DECODER
E2POT™ is a trademark of Xicor, Inc.
6732-2.0 5/30/97 T1/C0/D0 SH
1
RESISTOR
ARRAY
VL
VW
6732 FM1
Characteristics subject to change without notice
X9315
PIN DESCRIPTIONS
VH and VL
The high (VH) and low (VL) terminals of the X9315 are
equivalent to the fixed terminals of a mechanical potenti-
ometer. 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.
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.
Up/Down (U/D)
The U/D input controls the direction of the wiper move-
ment and whether the counter is incremented or decre-
mented.
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
VH
VSS
18
27
X9315
36
45
VCC
CS
VL
VW
PIN NAMES
Symbol
VH
VW
VL
VSS
VCC
U/D
INC
CS
6732 FM2
Description
High Terminal
Wiper Terminal
Low Terminal
Ground
Supply Voltage
Up/Down Input
Increment Input
Chip Select Input
6732 FM T01
2
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