Overview
The PCA9545APW, produced by Texas Instruments, is a quad bidirectional translating switch controlled via the I2C bus. This device allows the SCL/SDA upstream pair to fan out to four downstream pairs or channels, enabling communication between multiple slave devices. The PCA9545APW supports voltage-level translation, allowing devices with different voltage levels (1.8 V, 2.5 V, 3.3 V, and 5 V) to communicate without additional protection. It also features interrupt logic and a reset function, making it versatile for various I2C and SMBus applications.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (VDD) | 2.3 | - | 5.5 | V |
| Operating Temperature Range | -40 | - | 85 | °C |
| Supply Current (IDD) | - | 10 | 30 | μA |
| Standby Current (Istb) | - | 0.1 | 1 | μA |
| Power-On Reset Voltage (VPOR) | 1.6 | - | 2.1 | V |
| LOW-Level Input Voltage (VIL) | -0.5 | - | 0.3VDD | V |
| HIGH-Level Input Voltage (VIH) | 0.7VDD | - | 6 | V |
| LOW-Level Output Current (IOL) | - | 6 | 10 | mA |
| Leakage Current (IL) | -1 | - | 1 | μA |
| Input Capacitance (Ci) | - | 10 | 13 | pF |
| Propagation Delay Time (tpd) | 0.3 | - | - | ns |
Key Features
- 1-of-4 bidirectional translating switches
- I2C bus and SMBus compatible
- Four active-low interrupt inputs and one active-low interrupt output
- Active-low reset input
- Two address terminals allowing up to four devices on the I2C bus
- Channel selection via I2C bus, in any combination
- Power-up with all switch channels deselected
- No glitch on power-up
- Supports hot insertion
- Low standby current
- Operating power-supply voltage range of 2.3 V to 5.5 V
- 5.5 V tolerant inputs
- 0 to 400-kHz clock frequency
- Latch-up performance exceeds 100 mA per JESD 78
- ESD protection exceeds JESD 22
- 2000-V Human-Body Model (A114-A) and 1000-V Charged-Device Model (C101)
Applications
The PCA9545APW is suitable for a variety of applications where multiple I2C or SMBus devices need to be connected and managed. This includes:
- Embedded systems requiring multiple I2C/SMBus interfaces
- Industrial automation and control systems
- Automotive systems with multiple sensor and actuator interfaces
- Consumer electronics with multiple peripheral devices
- Medical devices requiring reliable and versatile I2C/SMBus communication
Q & A
- What is the PCA9545APW used for? The PCA9545APW is a quad bidirectional translating switch used to manage multiple I2C or SMBus devices, allowing a single master to communicate with up to four slave devices.
- What voltage levels does the PCA9545APW support? The PCA9545APW supports voltage-level translation between 1.8 V, 2.5 V, 3.3 V, and 5 V buses.
- How many interrupt inputs does the PCA9545APW have? The PCA9545APW has four active-low interrupt inputs and one active-low interrupt output.
- What is the purpose of the reset input on the PCA9545APW? The active-low reset input allows the device to recover from a situation where one of the downstream I2C buses is stuck in a low state.
- What is the operating temperature range of the PCA9545APW? The operating temperature range is from -40°C to 85°C.
- Is the PCA9545APW compatible with SMBus standards? Yes, the PCA9545APW is compatible with SMBus standards in addition to I2C bus standards.
- What is the maximum clock frequency supported by the PCA9545APW? The PCA9545APW supports clock frequencies up to 400 kHz.
- Does the PCA9545APW support hot insertion? Yes, the PCA9545APW supports hot insertion.
- What is the standby current of the PCA9545APW? The standby current is typically 0.1 μA to 1 μA.
- What kind of ESD protection does the PCA9545APW offer? The PCA9545APW offers ESD protection exceeding JESD 22 standards, including 2000-V Human-Body Model and 1000-V Charged-Device Model.
