The NCA9547A is an octal bidirectional translating multiplexer controlled by the I²C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Only one SCn/SDn 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 controller and downstream devices (targets) on that channel.
An active LOW reset input allows the NCA9547A to recover from a situation where one of the downstream I²C-buses is stuck in a LOW state. Pulling the RESETpin LOW resets the I²C-bus state machine causing all the channels to be deselected, except Channel 0 so that the controller can regain control of the bus.
The pass gates of the multiplexers are constructed such that the VCC pin can be used to limit the maximum high voltage which will be passed by the NCA9547A. 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 6 V tolerant.
Features and benefits
1-of-8 bidirectional translating multiplexers
I²C-bus interface logic; compatible with SMBus standards
Active LOW reset input
Three address pins allowing up to eight devices on the I²C-bus
Channel selection via I²C-bus, one channel at a time
Power-up with all channels deselected, except channel 0 which is connected
Low Ron 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 1.65 V to 5.5 V
6 V tolerant inputs
0 Hz to 400 kHz clock frequency
Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
Two packages offered: TSSOP24, and HWQFN24
ESD protection:
HBM: ANSI/ESDA/JEDEC JS-001 class 2 exceeds 2 kV
CDM: ANSI/ESDA/JEDEC JS-002 class C3 exceeds 1 kV
Specified from -40 °C to +85 °C and from -40 °C to +125 °C
The NCA9547A is an octal bidirectional translating multiplexer controlled by the I²C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Only one SCn/SDn 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 controller and downstream devices (targets) on that channel.
An active LOW reset input allows the NCA9547A to recover from a situation where one of the downstream I²C-buses is stuck in a LOW state. Pulling the RESETpin LOW resets the I²C-bus state machine causing all the channels to be deselected, except Channel 0 so that the controller can regain control of the bus.
The pass gates of the multiplexers are constructed such that the VCC pin can be used to limit the maximum high voltage which will be passed by the NCA9547A. 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 6 V tolerant.
Features and benefits
- 1-of-8 bidirectional translating multiplexers
- I²C-bus interface logic; compatible with SMBus standards
- Active LOW reset input
- Three address pins allowing up to eight devices on the I²C-bus
- Channel selection via I²C-bus, one channel at a time
- Power-up with all channels deselected, except channel 0 which is connected
- Low Ron 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 1.65 V to 5.5 V
- 6 V tolerant inputs
- 0 Hz to 400 kHz clock frequency
- Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
- Two packages offered: TSSOP24, and HWQFN24
- ESD protection:
- HBM: ANSI/ESDA/JEDEC JS-001 class 2 exceeds 2 kV
- CDM: ANSI/ESDA/JEDEC JS-002 class C3 exceeds 1 kV
- Specified from -40 °C to +85 °C and from -40 °C to +125 °C
