APPLICATION NOTE
A V A I L A B L E
AN20 • AN42–48 • AN50-53 • AN73 • AN99 • AN115 • AN120 • AN124 • AN133 • AN134 • AN135
Low Power/2-Wire Serial Bus
X9241
Quad Digitally Controlled Potentiometer (XDCP™)
FEATURES
DESCRIPTION
• Four potentiometers in one package
• 2-wire serial interface
• Register oriented format
The X9241 integrates four digitally controlled
potentiometers (XDCP) on a monolithic CMOS
integrated microcircuit.
—Direct read/write/transfer of wiper positions
—Store as many as four positions per
potentiometer
• Terminal Voltages: ±5V
• Cascade resistor arrays
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.
• Low power CMOS
• High Reliability
—Endurance–100,000 data changes per bit per
register
—Register data retention–100 years
• 16-bytes of nonvolatile memory
• 3 resistor array values
—2KΩ to 50KΩ mask programmable
—Cascadable for values of 500Ω to 200KΩ
• Resolution: 64 taps each pot
• 20-lead plastic DIP, 20-lead TSSOP and 20-lead
SOIC packages
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
V
CC
SS
V
R
/
H2
R0
R2
V
/R
R0
R2
R1
R3
R1
R3
H0 H0
Wiper
Counter
Register
H2
Wiper
Counter
Register
(WCR)
Register
Array
Pot 2
(WCR)
V
/R
V
V
/R
L0 L0
L2 L2
/R
V
/R
W2 W2
W0 W0
SCL
SDA
Interface
and
Control
Circuitry
A0
A1
A2
A3
8
Data
V
/R
H1 H1
V
/R
H3 H3
R0
R2
R1
R3
R0
R2
R1
R3
Wiper
Counter
Register
(WCR)
Wiper
Counter
Register
(WCR)
Register
Array
Pot 3
Register
Array
Pot 1
V
V
/R
L1 L1
V
V
/R
L3 L3
/R
W1 W1
/R
W3 W3
Characteristics subject to change without notice. 1 of 18
REV 1.1 10/6/00
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