A
PPLICATION
N
OTES
A V A I L A B L E
AN20 • AN42 • AN44–48 • AN50 • AN52 • AN53 • AN73
Advance
Voltage
X9221
Information
±
5V,
Terminal
64 Taps
X9221
Dual E
2
POT
™
Nonvolatile Digital Potentiometer
FEATURES
DESCRIPTION
The X9221 integrates two nonvolatile E
2
POT™ digitally
controlled potentiometers on a monolithic CMOS micro-
circuit.
The X9221 contains two resistor arrays, each com-
posed of 63 resistive elements. Between each element
and at either end are tap points accessible to the wiper
elements. The position of the wiper element on the array
is controlled by the user through the two-wire serial bus
interface.
Each resistor array has associated with it a wiper counter
register and four 8-bit data registers that can be directly
written and read by the user. The contents of the wiper
counter register control the position of the wiper on the
resistor array.
The data register may be read or written by the user. The
contents of the data registers can be transferred to the
wiper counter register to position the wiper. The current
wiper position can be transferred to any one of its
associated data registers.
•
•
•
•
•
•
•
•
•
•
Two E
2
POTs in One Package
Two-Wire Serial Interface
Register Oriented Format
—Directly Write Wiper Position
—Read Wiper Position
—Store as Many as Four Positions per Pot
Instruction Format
—Quick Transfer of Register Contents to
Resistor Array
Low Power CMOS
Direct Write Cell
—Endurance - 100,000 Writes per Register
—Register Data Retention - 100 years
8 Bytes of E
2
PROM memory
3 Resistor Array Values
—2K
Ω
to 50K
Ω
Mask Programmable
Resolution: 64 Taps each Pot
20-Lead Plastic DIP and 20-Lead SOIC Packages
FUNCTIONAL DIAGRAM
R0 R1
WIPER
COUNTER
REGISTER
(WCR)
R2 R3
SCL
SDA
A0
A1
A2
A3
VH0
VL0
VW0
INTERFACE
AND
CONTROL
CIRCUITRY
8
DATA
R0 R1
VH1
WIPER
COUNTER RESISTOR
ARRAY
REGISTER
POT 1
(WCR)
R2 R3
VL1
VW1
3079 ILL F07.1
© Xicor, Inc. 1994, 1995, 1996 Patents Pending.
3079-1.6 6/12/96 T1/C1/D0 NS
1
Characteristics subject to change without notice
XICOR [ XICOR INC. ]
