A1

A0

SDA

SCL

INT

GND

P6

P0

P1

P2

P3

P4

P5

P7

INT

GND

VCC

VCC

VCC

10 k

(1)

10 k

(1)

10 k

10 k

2 k

100 k

(x 3)

Master

Controller

TCA9538

INT

RESET

Subsystem 2

(e.g., counter)

Subsystem 3

(e.g., alarm system)

ALARM

Controlled Device

(e.g., CBT device)

ENABLE

A

B

VCC

RESET

RESET

Subsystem 1

(e.g., temperature sensor)

SDA

SCL

15

14

16

13

3

2

1

8

12

11

10

9

7

6

5

4

23

TCA9538

www.ti.com

SCPS199D – AUGUST 2014 – REVISED OCTOBER 2016

Product Folder Links: TCA9538

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Copyright © 2014–2016, Texas Instruments Incorporated

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 24 shows an application in which the TCA9538 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, increases as a result.

A.

Device address is configured as 1110000 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 24. Application Schematic