CAT5409

Doc. No. MD-2010 Rev. M

2

© 2009 SCILLC. All rights reserved.

Characteristics subject to change without notice

PIN DESCRIPTIONS

SCL: Serial Clock

The CAT5409 serial clock input pin is used to clock all

data transfers into or out of the device.

SDA: Serial Data

The CAT5409 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 outputs.

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 CAT5409.

terminal connections on a mechanical potentiometer.

a mechanical potentiometer.

WP

¯¯¯: Write Protect Input

The WP

¯¯¯ pin when tied low prevents non-volatile writes

to the data registers (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 7 for more details.

DEVICE OPERATION

The CAT5409 is four resistor arrays integrated with I²C serial interface logic, four 6-bit wiper control registers and

sixteen 6-bit, non-volatile memory data registers. Each resistor array contains 63 separate resistive elements

connected in series. The physical ends of each array are equivalent to the fixed terminals of a mechanical

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 allows 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.

Pin#

(SOIC)

Pin#

(TSSOP) Name Function

19

1

Supply Voltage

20

2

Low Reference Terminal

for Potentiometer 0

21

3

High Reference Terminal

for Potentiometer 0

22

4

Wiper Terminal for

Potentiometer 0

23

5

A2

Device Address

24

6

WP

¯¯¯

Write Protection

1

7

SDA

Serial Data Input/Output

2

8

A1

Device Address

3

9

Low Reference Terminal

for Potentiometer 1

4

10

High Reference Terminal

for Potentiometer 1

5

11

Wiper Terminal for

Potentiometer 1

6

12

GND

Ground

7

13

NC

No Connect

8

14

Wiper Terminal for

Potentiometer 2

9

15

High Reference Terminal

for Potentiometer 2

10

16

Low Reference Terminal

for Potentiometer 2

11

17

SCL

Bus Serial Clock

12

18

A3

Device Address

13

19

NC

No Connect

14

20

A0

Device Address, LSB

15

21

Wiper Terminal for

Potentiometer 3

16

22

High Reference Terminal

for Potentiometer 3

17

23

Low Reference Terminal

for Potentiometer 3

18

24

NC

No Connect