A
PPLICATION
N
OTES
A V A I L A B L E
AN99 • AN115 • AN120 • AN124 • AN133 • AN134 • AN135
Low Noise/Low Power/2-Wire Bus
X9428
Single Digitally Controlled Potentiometer (XDCP
™
)
FEATURES
• Solid state potentiometer
• 2-wire serial interface
• Register oriented format
—Direct Read/Write/Transfer Wiper Position
—Store as many as Four Positions per
Potentiometer
• Power supplies
—V
CC
= 2.7V to 5.5V
—V+ = 2.7V to 5.5V
—V– = –2.7V to –5.5V
• Low power CMOS
—Standby current < 1µA
—Ideal for Battery Operated Applications
• High reliability
—Endurance–100,000 Data Changes per Bit per
Register
—Register Data Retention–100 years
• 4-bytes of nonvolatile memory
• 10K Ohm resistor array
• Resolution: 64 taps each potentiometer
• SOIC and TSSOP packages
DESCRIPTION
The X9428 integrates a digitally controlled
potentiometers (XDCP) on a monolithic CMOS
integrated microcircuit.
The digitally controlled potentiometer is implemented
using 63 resistive elements in a series array. Between
each element are tap points connected to the wiper
terminal through switches. The position of the wiper on
the array is controlled by the user through the 2-wire
bus interface. Each potentiometer has associated with
it a volatile Wiper Counter Register (WCR) and 4
nonvolatile Data Registers (DR0:DR3) that can be
directly written to and read by the user. The contents of
the WCR controls the position of the wiper on the
resistor array through the switches. Power up recalls
the contents of DR0 to the WCR.
The XDCP 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, and signal processing.
BLOCK DIAGRAM
V
CC
V
SS
V+
V–
R0 R1
Interface
and
Control
Circuitry
Data
WP
V
H
/R
H
SCL
SDA
A0
A2
A3
8
R2 R3
Wiper
Counter
Register
(WCR)
V
L
/R
L
V
W
/R
W
REV 1.1.5 7/8/03
www.xicor.com
Characteristics subject to change without notice.
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XICOR [ XICOR INC. ]
