Overview
The PCA9518PW is an expandable five-channel bidirectional buffer designed for I2C and SMBus applications, manufactured by Texas Instruments. This device is crucial for overcoming the limitations of the I2C protocol, particularly the maximum bus capacitance of 400 pF, which is derived from the number of devices on the I2C bus and the bus length. The PCA9518PW separates and buffers the I2C data (SDA) and clock (SCL) lines into multiple groups of 400-pF segments, ensuring only one repeater delay per segment-to-segment transition. This allows for the creation of larger I2C networks without degrading system performance.
Key Specifications
| Parameter | Value |
|---|---|
| Package | TSSOP (PW) with 20 pins |
| Operating Temperature Range | -40°C to 85°C |
| Operating VCC Range | 3 V to 3.6 V |
| I2C Bus Frequency | Up to 400 kHz |
| I2C and Enable Input Pins | 5-V tolerant |
| ESD Protection | 2000-V Human-Body Model, 200-V Machine Model, 1000-V Charged-Device Model |
| Latchup Performance | Exceeds 100 mA per JESD 78 |
Key Features
- Expandable five-channel bidirectional buffer for I2C and SMBus applications
- 400-kHz fast I2C bus support
- Operating VCC range of 3 V to 3.6 V with 5-V tolerant I2C and enable input pins
- Active-high individual repeater enable inputs
- Open-drain input/outputs
- Lockup-free operation and support for multiple masters
- Powered-off high-impedance I2C pins
- I2C bus and SMBus compatibility
- Internal power-on-reset circuit (VPOR)
- Requires pullup resistors on each SDA and SCL line
Applications
The PCA9518PW is designed to work in various I2C and SMBus systems, including those requiring standard-mode and fast-mode I2C devices. It is particularly useful in applications where the I2C bus needs to be extended beyond the standard 400 pF capacitance limit, such as in industrial control systems, automotive systems, and consumer electronics. The device can also be used to translate signals between 3 V and 5 V systems, making it versatile for mixed-mode signal operations.
Q & A
- What is the primary function of the PCA9518PW?
The PCA9518PW is an expandable five-channel bidirectional buffer for I2C and SMBus applications, designed to overcome the bus capacitance limitations of the I2C protocol.
- What is the operating temperature range of the PCA9518PW?
The operating temperature range of the PCA9518PW is -40°C to 85°C.
- What is the maximum I2C bus frequency supported by the PCA9518PW?
The PCA9518PW supports I2C bus frequencies up to 400 kHz.
- Does the PCA9518PW support clock stretching across the repeater?
No, the PCA9518PW does not support clock stretching across the repeater.
- Can the PCA9518PW be used in mixed-mode signal operations?
- What type of ESD protection does the PCA9518PW offer?
The PCA9518PW offers ESD protection exceeding 2000-V Human-Body Model, 200-V Machine Model, and 1000-V Charged-Device Model.
- How does the PCA9518PW handle latchup conditions?
The PCA9518PW has lockup-free operation and latchup performance exceeding 100 mA per JESD 78.
- Can multiple PCA9518PW devices be grouped together?
- What is the purpose of the internal power-on-reset circuit (VPOR) in the PCA9518PW?
The internal power-on-reset circuit (VPOR) allows for an initial condition and the ramping of VCC to set the internal logic.
- Are pullup resistors required for the PCA9518PW?
- Can the PCA9518PW be used with standard-mode and fast-mode I2C devices?
