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
X9409
FEATURES
• Four potentiometers per package
• 64 resistor taps
• 2-wire serial interface for write, read, and trans-
fer operations of the potentiometer
• 50
Ω
Wiper resistance, typical at 5V.
• Four non-volatile data registers for each
potentiometer
• Non-volatile storage of multiple wiper position
• Power on recall. Loads saved wiper position on
power up.
• Standby current < 1µA typical
• System V
CC
: 2.7V to 5.5V operation
• 10K
Ω
, 2.5K
Ω
End to end resistance
• 100 yr. data retention
• Endurance: 100,000 data changes per bit per
register
• Low power CMOS
• 24-lead SOIC, 24-lead TSSOP, and
24-lead CSP (Chip Scale Package) Packages
DESCRIPTION
Preliminary Information
Quad Digitally Controlled Potentiometers (XDCP
™
)
The X9409 integrates 4 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
R
0
R
1
Pot 0
Wiper
Counter
Register
(WCR)
V
H0
/R
HO
R
0
R
1
Wiper
Counter
Register
(WCR)
Resistor
Array
Pot 2
V
H2
/R
H2
WP
SCL
SDA
A0
A1
A2
A3
R
2
R
3
V
L0
/
R
LO
V
W0
/
R
WO
R
2
R
3
V
L2
/R
L2
V
W2
/R
W2
Interface
and
Control
Circuitry
Data
8
V
W1
/
R
W1
R
0
R
1
Wiper
Counter
Register
(WCR)
Resistor
Array
Pot 1
V
H1
/
R
H1
V
L1
/R
L1
R
0
R
1
Wiper
Counter
Register
(WCR)
Resistor
Array
Pot 3
V
W3
/R
W3
V
H3
/R
H3
R
2
R
3
R
2
R
3
V
L3
/R
L3
REV 1.6 1/30/03
www.xicor.com
Characteristics subject to change without notice.
1 of 21
XICOR [ XICOR INC. ]
