PCA9846
PCA9846 is 4-channel ultra-low voltage Fm+ I2C-bus switch manufactured by NXP Semiconductors.
4-channel ultra-low voltage, Fm+ I2C-bus switch with reset
Rev. 1.1
- 4 April 2017
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 VDD1 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 municate 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; patible 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 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 mand
- I2C Device ID function
- No glitch on power-up
- Supports hot insertion since all channels are de-selected at power-on
- Low standby current
NXP...