The NCA9548A is an octal bidirectional translating switch controlled via the I²C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can be selected, determined by the contents of the programmable control register.
An active LOW reset input allows the NCA9548A 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 and causes all the channels to be deselected as does the internal Power-on reset function.
The pass gates of the switches are constructed such that the VCC pin can be used to limit the maximum high voltage which will be passed by the NCA9548A. This allows the use of different bus voltages on each pair, so that 1.8 V or 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 switches
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, in any combination
Power-up with all switch channels deselected
Low Ron switches
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 NCA9548A is an octal bidirectional translating switch controlled via the I²C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can be selected, determined by the contents of the programmable control register.
An active LOW reset input allows the NCA9548A 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 and causes all the channels to be deselected as does the internal Power-on reset function.
The pass gates of the switches are constructed such that the VCC pin can be used to limit the maximum high voltage which will be passed by the NCA9548A. This allows the use of different bus voltages on each pair, so that 1.8 V or 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 switches
- 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, in any combination
- Power-up with all switch channels deselected
- Low Ron switches
- 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
