ISL23345

FN7872 Rev 0.00

Page 13 of 19

June 21, 2011

Functional Pin Descriptions

Potentiometers Pins

RHI AND RLI

The high (RHi, i = 0, 1, 2, 3) and low (RLi, i = 0, 1, 2, 3) terminals

of the ISL23345 are equivalent to the fixed terminals of a

mechanical potentiometer. RHi and RLi are referenced to the

relative position of the wiper and not the voltage potential on the

terminals. With WRi set to 255 decimal, the wiper will be closest

to RHi, and with the WRi set to 0, the wiper is closest to RLi.

RWI

RWi (i = 0, 1, 3) is the wiper terminal, and it is equivalent to the

movable terminal of a mechanical potentiometer. The position of

the wiper within the array is determined by the WRi register.

VCC

Power terminal for the potentiometer section analog power source.

Can be any value needed to support the voltage range of the DCP

pins, from 1.7V to 5.5V, independent of the VLOGIC voltage.

Bus Interface Pins

SERIAL DATA INPUT/OUTPUT (SDA)

The SDA is a bidirectional serial data input/output pin for I2C

interface. It receives device address, wiper address and data

from an I2C external master device at the rising edge of the serial

clock SCL, and it shifts out data after each falling edge of the

serial clock.

SDA requires an external pull-up resistor, since it is an open drain

input/output.

SERIAL CLOCK (SCL)

This input is the serial clock of the I2C serial interface. SCL

requires an external pull-up resistor, since a master is an open

drain output.

DEVICE ADDRESS (A2, A1, A0)

The address inputs are used to set the least significant 3 bits of

the 7-bit I2C interface slave address. A match in the slave

address serial data stream must match with the Address input

FIGURE 21. WIPER LARGE SIGNAL SETTLING TIME

FIGURE 22. POWER-ON START-UP IN VOLTAGE DIVIDER MODE

FIGURE 23. 10k

 -3dB CUT OFF FREQUENCY

FIGURE 24. STANDBY CURRENT vs TEMPERATURE

Typical Performance Curves (Continued)

SCL 9TH CLOCK OF THE

DATA BYTE (ACK)

1V/DIV

0.2µs/DIV

WIPER

SCL

0.5V/DIV

20µs/DIV

VCC

WIPER

0.5V/DIV, 0.2µs/DIV

-3dB FREQUENCY = 1.437MHz AT MIDDLE TAP

CH1: RH TERMINAL

CH2: RW TERMINAL

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

-40

-15

10

35

60

85

110

VCC = 1.7V, VLOGIC = 1.2V

VCC = 5.5V, VLOGIC = 5.5V

TEMPERATURE (°C)