CAT5259_08 Datasheet, PDF (2/16 Pages) Catalyst Semiconductor – Quad Digitally Programmable Potentiometers (DPP™) with 256 Taps and I²C Interface

CAT5259
PIN DESCRIPTIONS
Pin
#
Name
Function
1 NC No Connect
2 A0 Device Address, LSB
3 R_W3 Wiper Terminal for Potentiometer 3
4 R_H3 High Reference Terminal for Potentiometer 3
5 R_L3 Low Reference Terminal for Potentiometer 3
6 NC No Connect
7 V_CC Supply Voltage
8 R_L0 Low Reference Terminal for Potentiometer 0
9 R_H0 High Reference Terminal for Potentiometer 0
10 R_W0 Wiper Terminal for Potentiometer 0
11 A2 Device Address
12 ¯W¯P¯ Write Protection
13 SDA Serial Data Input/Output
14 A1 Device Address
15 R_L1 Low Reference Terminal for Potentiometer 1
16 R_H1 High Reference Terminal for Potentiometer 1
17 R_W1 Wiper Terminal for Potentiometer 1
18 GND Ground
19 NC No Connect
20 R_W2 Wiper Terminal for Potentiometer 2
21 R_H2 High Reference Terminal for Potentiometer 2
22 R_L2 Low Reference Terminal for Potentiometer 2
23 SCL Bus Serial Clock
24 A3 Device Address
SCL: Serial Clock
The CAT5259 serial clock input pin is used to
clock all data transfers into or out of the device.
SDA: Serial Data
The CAT5259 bidirectional serial data pin is
used to transfer data into and out of the device.
The SDA pin is an open drain output and can
be wire-Ored with the other open drain or open
collector I/Os.
A0, A1, A2, A3: Device Address Inputs
These inputs set the device address when
addressing multiple devices. A total of sixteen
devices can be addressed on a single bus. A
match in the slave address must be made with
the address input in order to initiate
communication with the CAT5259.
R_H, R_L: Resistor End Points
The four sets of R_H and R_L pins are equivalent
to the terminal connections on a mechanical
potentiometer.
R_W: Wiper
The four R_W pins are equivalent to the wiper
terminal of a mechanical potentiometer.
¯W¯P¯: _{Write Protect Input}
The ^{¯W¯P¯} pin when tied low prevents non-volatile
writes to the device (change of wiper control
register is allowed) and when tied high or left
floating normal read/write operations are
allowed. See Write Protection on page 6 for
more details.
DEVICE OPERATION
The CAT5259 is four resistor arrays integrated with a I²C serial interface logic, four 8-bit wiper control registers
and sixteen 8-bit, non-volatile memory data registers. Each resistor array contains 255 separate resistive
elements connected in series. The physical ends of each array are equivalent to the fixed terminals of a
mechanical potentiometer (R_H and R_L). The tap positions between and at the ends of the series resistors are
connected to the output wiper terminals (R_W) by a CMOS transistor switch. Only one tap point for each
potentiometer is connected to its wiper terminal at a time and is determined by the value of the wiper control
register. Data can be read or written to the wiper control registers or the non-volatile memory data registers via
the I²C bus. Additional instructions allow data to be transferred between the wiper control registers and each
respective potentiometer's non-volatile data registers. Also, the device can be instructed to operate in an
"increment/decrement" mode.
Doc. No. MD-2000 Rev. H
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice