CAT5409WI-25 Datasheet, PDF (2/16 Pages) ON Semiconductor – Quad Digitally Programmable Potentiometers with 64 Taps and I²C Interface

CAT5409
PIN DESCRIPTIONS
Pin#
(SOIC)
19
20
21
22
23
24
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Pin#
(TSSOP)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Name
V_CC
R_L0
R_H0
R_W0
A2
¯W¯P¯
SDA
A1
R_L1
R_H1
R_W1
GND
NC
R_W2
R_H2
R_L2
SCL
A3
NC
A0
R_W3
R_H3
R_L3
NC
Function
Supply Voltage
Low Reference Terminal
for Potentiometer 0
High Reference Terminal
for Potentiometer 0
Wiper Terminal for
Potentiometer 0
Device Address
Write Protection
Serial Data Input/Output
Device Address
Low Reference Terminal
for Potentiometer 1
High Reference Terminal
for Potentiometer 1
Wiper Terminal for
Potentiometer 1
Ground
No Connect
Wiper Terminal for
Potentiometer 2
High Reference Terminal
for Potentiometer 2
Low Reference Terminal
for Potentiometer 2
Bus Serial Clock
Device Address
No Connect
Device Address, LSB
Wiper Terminal for
Potentiometer 3
High Reference Terminal
for Potentiometer 3
Low Reference Terminal
for Potentiometer 3
No Connect
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.
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 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
potentiometer (R_H and R_L). R_H and R_L are symmetrical and may be interchanged. 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 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.
Doc. No. MD-2010 Rev. L
2
© 2008 SCILLC. All rights reserved.
Characteristics subject to change without notice