REV 1.1.7 2/6/03
Characteristics subject to change without notice.
1 of 24
www.xicor.com
X9279
Single Digitally-Controlled (XDCP
TM
) Potentiometer
FEATURES
256 Resistor Taps
2-Wire Serial Interface for write, read, and
transfer operations of the potentiometer
Wiper Resistance, 100
16 Nonvolatile Data Registers for Each
Potentiometer
Nonvolatile Storage of Multiple Wiper Positions
Power On Recall. Loads Saved Wiper Position on
Power Up.
Standby Current < 5μA Max
V
CC
: 2.7V to 5.5V Operation
50K
, 100K
versions of End to End Resistance
Endurance: 100,000 Data Changes per Bit per
Register
100 yr. Data Retention
14-Lead TSSOP, 16-Lead CSP (Chip Scale
Package)
Low Power CMOS
typical @ 5V
DESCRIPTION
The X9279 integrates a single digitally controlled
potentiometer (XDCP) on a monolithic CMOS
integrated circuit.
The digital controlled potentiometer is implemented
using 255 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. The potentiometer has associated with it
a volatile Wiper Counter Register (WCR) and a four
nonvolatile Data Registers 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
though the switches. Powerup recalls the contents of
the default data register (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.
Single Supply / Low Power / 256-tap / 2-Wire Bus
A
PPLICATION
N
OTES
AND
D
EVELOPMENT
S
YSTEM
A V A I L A B L E
AN99 AN115 AN124 AN133 AN134 AN135
FUNCTIONAL DIAGRAM
256-taps
50K
and 100K
R
H
R
L
R
W
POT
V
CC
V
SS
2-Wire
Bus
Interface
wiper
Power On Recall
Wiper Counter
Register (WCR)
Data Registers
16 Bytes
Bus
Interface
and Control
Address
Data
Status
Write
Read
Transfer
Inc/Dec
Control