1
FN8175.4
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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| Intersil (and design) is a registered trademark of Intersil Americas Inc.
XDCP is a trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2005, 2009. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
X9279
Single Supply/Low Power/256-Tap/2-Wire Bus
Single Digitally-Controlled (XDCP™)
Potentiometer
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 non-volatile 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. Power-up 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.
Features
• 256 Resistor Taps
• 2-Wire Serial Interface for Write, Read, and Transfer
Operations of the Potentiometer
• Wiper Resistance, 100 Typical @ 5V
• 16 Non-volatile Data Registers for Each Potentiometer
• Non-volatile 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 Ld TSSOP
• Low Power CMOS
• Pb-Free Available (RoHS Compliant)
Functional Diagram
256-TAPS
50k and 100k
R
H
R
L
R
W
POT
V
CC
V
SS
2-WIRE
BUS
WIPER
INTERFACE
POWER-ON RECALL
WIPER COUNTER
REGISTER (WCR)
DATA REGISTERS
16 BYTES
BUS
INTERFACE
AND
ADDRESS
DATA
STATUS
WRITE
READ
TRANSFER
INC/DEC
CONTROL
CONTROL
Data Sheet September 23, 2009
O
BS
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R
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B
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U
B
S
T
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C
T
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L
9
5
8
1
0
,
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1
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