1. General description
The PCA9547 is an octal bidirectional translating multiplexer controlled by the I
2
C-bus.
The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Only one
SCx/SDx channel can be selected at a time, determined by the contents of the
programmable control register. The device powers up with Channel 0 connected, allowing
immediate communication between the master and downstream devices on that channel.
An active LOW reset input allows the PCA9547 to recover from a situation where one of
the downstream I
2
C-buses is stuck in a LOW state. Pulling the RESET pin LOW resets
the I
2
C-bus state machine causing all the channels to be deselected, except Channel 0 so
that the master can regain control of the bus.
The pass gates of the multiplexers are constructed such that the V
DD
pin can be used to
limit the maximum high voltage which will be passed by the PCA9547. This allows the use
of different bus voltages on each 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 and benefits
1-of-8 bidirectional translating multiplexer
I
2
C-bus interface logic; compatible with SMBus standards
Active LOW RESET
input
3 address pins allowing up to 8 devices on the I
2
C-bus
Channel selection via I
2
C-bus, one channel at a time
Power-up with all channels deselected except Channel 0 which is connected
Low R
on
multiplexers
Allows voltage level translation between 1.8 V, 2.5 V, 3.3 V and 5 V buses
No glitch on power-up
Supports hot insertion
Low standby current
Operating power supply voltage range of 2.3 V to 5.5 V
5 V tolerant inputs
0 Hz to 400 kHz clock frequency
ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per
JESD22-C101
Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
Packages offered: SO24, TSSOP24, HVQFN24
PCA9547
8-channel I
2
C-bus multiplexer with reset
Rev. 4 — 1 April 2014 Product data sheet
