X9258 Datasheet, PDF (2/20 Pages) Xicor Inc. – Quad Digital Controlled Potentiometers (XDCP)

X9258
PIN DESCRIPTIONS
Host Interface Pins
SERIAL CLOCK (SCL)
The SCL input is used to clock data into and out of the
X9258.
SERIAL DATA (SDA)
SDA is a bidirectional pin used to transfer data into
and out of the device. It is an open drain output and
may be wire-ORed with any number of open drain or
open collector outputs. An open drain output requires
the use of a pull-up resistor. For selecting typical
values, refer to the guidelines for calculating typical
values on the bus pull-up resistors graph.
DEVICE ADDRESS (A₀ - A₃)
The Address inputs are used to set the least
significant 4 bits of the 8-bit slave address. A match in
the slave address serial data stream must be made
with the address input in order to initiate
communication with the X9258. A maximum of 16
devices may occupy the 2-wire serial bus.
Potentiometer Pins
V_H/R_H (V_H0/R_H0 - V_H3/R_H3), V_L/R_L (V_L0/R_L0 -
V_L3/R_L3)
The V_H/R_H and V_L/R_L inputs are equivalent to the
terminal connections on either end of a mechanical
potentiometer.
V_W/R_W (V_W0/R_W0 - V_W3/R_W3)
The wiper outputs are equivalent to the wiper output of
a mechanical potentiometer.
Hardware Write Protect Input (WP)
The WP pin when low prevents nonvolatile writes to
the Data Registers.
Analog Supplies V+, V-
The Analog Supplies V+, V- are the supply voltages for
the DCP analog section.
PIN CONFIGURATION
NC
A0
V_W3/R_W3
V_H3/R_H3
V_L3/R_L3
V+
V_CC
V_L0/R_L0
V_H0/R_H0
V_W0/R_W0
A2
WP
SOIC/TSSOP
1
24
2
23
3
22
4
21
5
20
6
19
X9258
7
18
8
17
9
16
10
15
11
14
12
13
A3
SCL
V_L2/R_L2
V_H2/R_H2
V_W2/R_W2
V–
V_SS
V_W1/R_W1
V_H1/R_H1
V_L1/R_L1
A1
SDA
PIN NAMES
Symbol
SCL
SDA
A0-A3
V_H0/R_H0 - V_H3/R_H3,
V_L0/R_L0 - V_L3/R_L3
V_W0/R_W0 - V_W3/R_W3
WP
V+,V-
V_CC
V_SS
NC
Description
Serial Clock
Serial Data
Device Address
Potentiometer Pins
(terminal equivalent)
Potentiometers Pins
(wiper equivalent)
Hardware Write Protection
Analog Supplies
System Supply Voltage
System Ground
No Connection (Allowed)
PRINCIPLES OF OPERATION
The X9258 is a highly integrated microcircuit
incorporating four resistor arrays and their associated
registers and counters and the serial interface logic
providing direct communication between the host and
the DCP potentiometers.
Serial Interface—2-Wire
The X9258 supports a bidirectional bus oriented
protocol. The protocol defines any device that sends
data onto the bus as a transmitter and the receiving
device as the receiver. The device controlling the
transfer is a master and the device being controlled is
the slave. The master will always initiate data transfers
2
FN8168.1
May 6, 2005