描述 Description

The PCA9847 is an ultra-low voltage, octal bidirectional translating multiplexer controlled viathe I2C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, orchannels. Any single SCx/SDx channel can be selected, determined by the programmablecontrol register. This feature allows multiple devices with the same I2C-busaddress to reside on the same bus. The multiplexer device can also separate a heavilyloaded I2C-bus into separate bus segments, eliminating the need for a busbuffer.
An active LOW reset input allows the PCA9847 to recover from a situation where one of thedownstream I2C-buses is stuck in a LOW state. Pulling the RESET pin LOW resets the I2C-bus state machineand deselects all the channels, as does the internal Power-On Reset (POR) function.
The pass gates of the multiplexers are constructed such that the VDD1 pin isused to limit the maximum high voltage which is passed by the PCA9847. This allows theuse of different bus voltages on each channel, so that 0.8 V, 1.8 V, 2.5 V or 3.3 Vparts can communicate without any additional protection. External pull-up resistors pullthe bus up to the desired voltage level for each channel. All I/O pins are 3.6 Vtolerant.

特性 Features

Ultra-low voltage operation, down to 0.8 V to interface with next-generation CPUs
1-of-8 bidirectional translating multiplexer
Fm+ I2C-bus interface logic; compatible with SMBus standards
Active LOW reset input
2 address pins allowing up to 16 devices on the I2C-bus
Channel selection via I2C-bus
Power-up with all multiplexer channels deselected
Low Ron switches
Allows voltage level translation between 0.8 V, 1.8 V, 2.5 V and 3.3 V buses
Reset via I2C-bus software command
I2C Device ID function
No glitch on power-up
Supports hot insertion since all channels are de-selected at power-on
Low standby current
3.6 V tolerant inputs
0 Hz to 1 MHz clock frequency
ESD protection exceeds 6000 V HBM per JESD22-A114 and 1000 V CDM perJESD22-C101
Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
Two packages offered: TSSOP24 and HVQFN24