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Product data sheet

Rev. 03 — 6 April 2005

5 of 25

Philips Semiconductors

PCA9546A

6.2 Pin description

[1]

pin must be connected to supply ground for proper device operation. For enhanced thermal, electrical, and

board-level performance, the exposed pad needs to be soldered to the board using a corresponding

thermal pad on the board, and for proper heat conduction through the board thermal vias need to be

incorporated in the PCB in the thermal pad region.

7.

Functional description

Refer to Figure 1 “Block diagram of PCA9546A” on page 3.

7.1 Device address

Following a START condition, the bus master must output the address of the slave it is

accessing. The address of the PCA9546A is shown in Figure 5. To conserve power, no

internal pull-up resistors are incorporated on the hardware selectable address pins and

they must be pulled HIGH or LOW.

The last bit of the slave address defines the operation to be performed. When set to

logic 1 a read is selected, while a logic 0 selects a write operation.

Table 3:

Pin description

Symbol

Pin

Description

SO, TSSOP

HVQFN

A0

1

15

address input 0

A1

2

16

address input 1

RESET

3

1

active LOW reset input

SD0

4

2

serial data 0

SC0

5

3

serial clock 0

SD1

6

4

serial data 1

SC1

7

5

serial clock 1

86 [1]

supply ground

SD2

9

7

serial data 2

SC2

10

8

serial clock 2

SD3

11

9

serial data 3

SC3

12

10

serial clock 3

A2

13

11

address input 2

SCL

14

12

serial clock line

SDA

15

13

serial data line

16

14

supply voltage

Fig 5.

Slave address

002aab189

1

1

1

0

A2

A1

A0 R/W

fixed

hardware

selectable