A1

A0

SDA

SCL

INT

GND

P06

P00

P01

P02

P03

P04

P05

P07

INT

GND

VCC

10 k

(1)

10 k

(1)

10 k

2 k

100 k

(x 3)

Master

Controller

PCF8575C

INT

RESET

Subsystem 2

(e.g., counter)

Subsystem 3

(e.g., alarm system)

ALARM

Controlled Device

(e.g., CBT device)

ENABLE

A

B

Subsystem 1

(e.g., temperature sensor)

SDA

SCL

23

22

24

1

3

2

21

12

11

10

9

8

7

6

5

4

A2

PCF8575C

www.ti.com

SCPS123F – MARCH 2005 – REVISED JANUARY 2015

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

Figure 15 shows an application in which the PCF8575C can be used.

9.2 Typical Application

(1)

The SCL and SDA pins must be tied directly to VCC because if SCL and SDA are tied to an auxiliary power supply

that could be powered on while VCC is powered off, then the supply current, ICC, will increase as a result.

A.

Device address is configured as 0100000 for this example.

B.

P0, P2, and P3 are configured as outputs.

C.

P1, P4, and P5 are configured as inputs.

D.

P6 and P7 are not used and must be configured as outputs.

Figure 15. Application Schematic

Copyright © 2005–2015, Texas Instruments Incorporated

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