PCA9846PWJ Datasheet, PDF (1/32 Pages) NXP Semiconductors – 4-channel ultra-low voltage, Fm+ I2C-bus switch with reset

PCA9846
4-channel ultra-low voltage, Fm+ I²C-bus switch with reset
Rev. 1 — 9 November 2015
Product data sheet
1. General description
The PCA9846 is an ultra-low voltage, quad bidirectional translating switch controlled via
the I²C-bus. The SCL/SDA upstream pair fans out to four downstream pairs, or channels.
Any or all SCx/SDx channels can be selected, determined by the programmable control
register. This feature allows multiple devices with the same I²C-bus address to reside on
the same bus. The switch device can also separate a heavily loaded I²C-bus into separate
bus segments, eliminating the need for a bus buffer.
An active LOW reset input allows the PCA9846 to recover from a situation where one of
the downstream I²C-buses is stuck in a LOW state. Pulling the RESET pin LOW resets
the I²C-bus state machine and deselects all the channels, as does the internal
Power-On Reset (POR) function.
The pass gates of the switches are constructed such that the V_DD1 pin is used to limit the
maximum high voltage which is passed by the PCA9846. This allows the use of different
bus voltages on each channel, so that 0.8 V, 1.8 V, 2.5 V or 3.3 V parts can communicate
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 3.6 V tolerant.
2. Features and benefits
 Ultra-low voltage operation, down to 0.8 V to interface with next-generation CPUs
 1-of-4 bidirectional translating switch
 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 switch channels deselected
 Low R_on 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