PCA9673_1

© NXP B.V. 2007. All rights reserved.

Product data sheet

Rev. 01 — 1 February 2007

6 of 33

NXP Semiconductors

PCA9673

[1]

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 PCA9673”.

7.1 Device address

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

accessing and the operation it wants to perform (read or write). The address of the

PCA9673 is shown in Figure 9. Slave address pins AD1 and AD0 choose 1 of 16 slave

addresses. To conserve power, no internal pull-up resistors are incorporated on AD1 and

AD0. Address values depending on AD1 and AD0 can be found in Table 3 “PCA9673

address map”.

Remark: The General Call address (0000 0000b) and the Device ID address

(1111 100Xb) are reserved and cannot be used as device address. Failure to follow this

requirement will cause the PCA9673 not to acknowledge.

with:

1111 111)

The last bit of the first byte defines the operation to be performed. When set to logic 1 a

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

SCL

22

19

serial clock line input

SDA

23

20

serial data line input/output

24

21

supply voltage

Table 2.

Symbol

Pin

Description

SO24, SSOP24,

TSSOP24, DHVQFN24

HVQFN24

Fig 9.

PCA9673 address

R/W

002aab636

A6

A5

A4

A3

A2

A1

A0

programmable

slave address