1.

General description

The SCL/SDA upstream pair fans out to four SCx/SDx downstream pairs, or channels.

Only one SCx/SDx channel is selected at a time, determined by the contents of the

programmable control register. Four interrupt inputs, INT0 to INT3, one for each of the

SCx/SDx downstream pairs, are provided. One interrupt output, INT, which acts as an

AND of the four interrupt inputs, is provided.

state machine with no channels selected.

limit the maximum high voltage which will be passed by the PCA9544A. This allows the

use of different bus voltages on each SCx/SDx pair, so that 1.8 V, 2.5 V or 3.3 V parts can

communicate with 5 V parts without any additional protection. External pull-up resistors

pull the bus up to the desired voltage level for each channel. All I/O pins are 5 V tolerant.

2.

Features

JESD22-A115 and 1000 V CDM per JESD22-C101

PCA9544A

Rev. 03 — 24 November 2008

Product data sheet