A
PPLICATION
N
OTES AND
D
EVELOPMENT
S
YSTEM
A V A I L A B L E
AN99 • AN115 • AN124 •AN133 • AN134 • AN135
Single Supply / Low Power / 256-tap / SPI bus
X9271
Single Digitally-Controlled (XDCP
TM
) Potentiometer
FEATURES
• 256 Resistor Taps
• SPI Serial Interface for write, read, and transfer
operations of the potentiometer
• Wiper Resistance, 100
Ω
typical @ V
CC
= 5V
• 16 Nonvolatile Data Registers
• Nonvolatile Storage of Multiple Wiper Positions
• Power On Recall. Loads Saved Wiper Position on
Power Up.
• Standby Current < 3µA Max
• V
CC
: 2.7V to 5.5V Operation
• 50K
Ω
, 100K
Ω
versions of End to End Resistance
• 100 yr. Data Retention
• Endurance: 100,000 Data Changes per Bit per
Register
• 14-Lead TSSOP, 16-Lead CSP (Chip Scale
Package)
• Low Power CMOS
DESCRIPTION
The X9271 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 SPI 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.
FUNCTIONAL DIAGRAM
V
CC
R
H
SPI
Bus
Interface
Address
Data
Status
Write
Read
Transfer
Inc/Dec
Bus
Interface
and Control
Control
Power On Recall
Wiper Counter
Register (WCR)
Data Registers
16 Bytes
50KΩ and 100KΩ
256-taps
POT
V
SS
R
W
R
L
REV 1.1.7 2/6/03
www.xicor.com
Characteristics subject to change without notice.
1 of 23
XICOR [ XICOR INC. ]
