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
X9418
Dual Digitally Controlled Potentiometers (XDCP
™
)
FEATURES
• Two potentiometers in one package
• 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
• 8-bytes of nonvolatile memory
• 2.5K
Ω
, 10K
Ω
resistor array
• Resolution: 64 taps each potentiometer
• 24-pin plastic DIP, 24-lead TSSOP and 24-lead
SOIC packages
DESCRIPTION
The X9418 integrates two 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
Wiper
Counter
Register
(WCR)
V
H0
/R
H0
WP
SCL
SDA
A0
A1
A2
A3
R2 R3
V
L0
/R
L0
V
W0
/R
W0
Interface
and
Control
Circuitry
8
Data
R0 R1
Wiper
Counter
Register
(WCR)
V
W1
/R
W1
V
H1
/R
H1
R2 R3
Resistor
Array
XDCP1
V
L1
/R
L1
REV 1.1.5 7/23/02
www.xicor.com
Characteristics subject to change without notice.
1 of 21
XICOR [ XICOR INC. ]
