PCA9518AD,118

Specialized Overview

The PCA9518AD,118 is an expandable five-channel I2C-bus hub manufactured by NXP Semiconductors. It buffers both data (SDA) and clock (SCL) lines to extend bus capacitance limits beyond the standard 400 pF restriction. The device operates within a supply voltage range of 2.3 V to 3.6 V and supports Standard-mode (up to 100 kHz) and Fast-mode (up to 400 kHz) communication. It features active HIGH individual enable inputs for each channel and provides lock-up free operation with powered-off high-impedance pins. The component is housed in a 20-lead SO plastic small outline package (SO20).

Specialized Feature Summary

• Expandable architecture allowing unlimited bus segmentation via dedicated expansion pins.
• Supports arbitration and clock stretching across repeaters without functional degradation.
• Includes powered-off high-impedance state for I/O pins when supply voltage is below threshold.

Specialized Applications

• I2C-bus system expansion where total capacitance exceeds 400 pF.
• Creating multiple master capable segments on a single I2C network.
• Interfacing between different voltage domains (e.g., 3.3 V and 5 V) using 5 V tolerant pins.

Specialized Procurement Notes

Verify the specific ordering suffix ',118' against official documentation to confirm packaging details such as reel size or tape specifications. Confirm that the SO20 package variant matches the required footprint for the target PCB design. Ensure compatibility with the intended operating temperature range of -40 °C to +85 °C.

Specialized Selection Notes

Select this component when designing systems requiring more than four channels or when individual channel enable/disable control is necessary. Note that if individual enable signals are required for all ports, only four ports are available per device because the fifth port lacks an enable pin. Verify that the expansion bus wiring requirements align with the four-wire expansion interface provided.

Specialized Part Context

This part belongs to the PCA9518A series, which is a wider voltage range version of the original PCA9518. It improves partial power-down performance compared to earlier iterations. The 'AD' designation specifically indicates the SO20 package type, distinguishing it from the TSSOP20 variant designated as 'APW'.

Specialized Replacement Considerations

The PCA9518APW serves as a package alternative offering identical electrical functionality but in a TSSOP20 form factor. Direct substitution requires verifying that the physical footprint on the printed circuit board accommodates the different package dimensions.