Overview
The PCA9546A, produced by Texas Instruments, is a 4-channel, bidirectional translating switch designed for I2C and SMBus applications. This device allows a single I2C master to communicate with multiple I2C slaves by directing the master SCL/SDA signal pair to four downstream channels. The PCA9546A supports both Standard-Mode (100 kHz) and Fast-Mode (400 kHz) operation, making it versatile for various I2C-based systems.
The device features an active-low RESET input, which helps in recovering from bus-fault conditions, and an internal power-on reset function that ensures all channels are deselected upon power-up. It also supports voltage-level translation between different bus voltages, enabling communication between 1.8-V, 2.5-V, 3.3-V, and 5-V parts without additional protection.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Power-Supply Voltage Range | 2.3 to 5.5 | V |
| Input Voltage Tolerance | -0.5 to 7 | V |
| Output Current | ±25 | mA |
| Operating Free-Air Temperature Range | -40 to 85 | °C |
| Clock Frequency Range | 0 to 400 | kHz |
| RON (On-Resistance) | Low RON switches | - |
| ESD Protection | 2000-V Human-Body Model, 1000-V Charged-Device Model | - |
| Latch-Up Performance | Exceeds 100 mA Per JESD 78 | - |
Key Features
- 1-of-4 bidirectional translating switches for I2C and SMBus compatibility
- Active-low RESET input for recovering from bus-fault conditions
- Three address pins, allowing up to eight PCA9546A devices on the I2C bus
- Channel selection via I2C bus, in any combination
- Power-up with all switch channels deselected
- Voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses
- No glitch on power-up and supports hot insertion
- Low standby current and 5.5 V tolerant inputs
Applications
The PCA9546A is suitable for a variety of applications where multiple I2C devices need to be managed by a single master. These include:
- Industrial automation systems requiring multiple sensor and actuator control
- Consumer electronics such as TVs, set-top boxes, and gaming consoles
- Automotive systems for managing various I2C-based peripherals
- Medical devices that require communication with multiple I2C slaves
- Embedded systems and IoT devices needing to interface with multiple I2C devices
Q & A
- What is the primary function of the PCA9546A?
The PCA9546A is a 4-channel, bidirectional translating switch for I2C and SMBus applications, allowing a single master to communicate with multiple slaves.
- What is the operating voltage range of the PCA9546A?
The operating power-supply voltage range is from 2.3 V to 5.5 V.
- How many PCA9546A devices can be connected on the same I2C bus?
Up to eight PCA9546A devices can be connected on the same I2C bus using the three address pins.
- What is the purpose of the active-low RESET input?
The active-low RESET input allows the device to recover from bus-fault conditions by resetting the I2C state machine and deselecting all channels.
- Does the PCA9546A support voltage-level translation?
Yes, the PCA9546A supports voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses.
- What is the maximum clock frequency supported by the PCA9546A?
The PCA9546A supports clock frequencies up to 400 kHz.
- Is the PCA9546A tolerant to high voltages on its inputs?
Yes, all I/O pins are 5.5 V tolerant.
- Does the PCA9546A support hot insertion?
Yes, the PCA9546A supports hot insertion.
- What is the typical application of the PCA9546A in industrial settings?
In industrial settings, the PCA9546A can be used to manage multiple sensors and actuators in automation systems.
- How does the PCA9546A handle power-on reset?
The PCA9546A has an internal power-on reset function that holds the device in a reset condition until the power supply voltage reaches a stable level, then initializes the device with all channels deselected.
