PCA9543AD,118

Specialized Overview

The PCA9543AD,118 is a bidirectional translating switch controlled by the I2C-bus, designed to fan out an upstream SCL/SDA pair to two downstream pairs. It operates within a supply voltage range of 2.3 V to 5.5 V and supports clock frequencies from 0 Hz to 400 kHz. The device features low on-state resistance, with maximum values of 55 Ohms at 2.3 V–2.7 V and 24 Ohms at 4.5 V–5.5 V. It includes active LOW interrupt inputs (INT0, INT1) and an interrupt output, alongside an active LOW reset input for bus recovery. The component is housed in an SOIC-14 package.

Specialized Feature Summary

• Provides two independent channels for bidirectional I2C/SMBus signal translation between different voltage levels.
• Integrates interrupt logic with dedicated inputs per channel and a combined open-drain output.
• Includes an active LOW reset function to recover from stuck bus conditions or power-on states.

Specialized Applications

• Expanding I2C bus capacity by connecting multiple slave devices across separate channels.
• Enabling communication between components operating at different voltage domains (e.g., 1.8 V, 2.5 V, 3.3 V, and 5 V).
• Managing hot insertion events on I2C buses without generating glitches.

Specialized Procurement Notes

Verify the ordering suffix '118' corresponds to the reel packing method specified in the NXP datasheet. Confirm the package type matches the SO14 (SOT108-1) outline dimensions. Ensure the device variant aligns with the PCA9543A fixed address map rather than the PCA9543B variant. Cross-reference the manufacturer designation with NXP Semiconductors documentation.

Specialized Selection Notes

Select this component when system design requires splitting a single I2C master into two isolated downstream buses. Consider the voltage translation capability if interfacing 5 V tolerant peripherals with lower voltage logic. Evaluate the interrupt requirements; if hardware interrupts are unnecessary, the INT pins can serve as general-purpose inputs with appropriate pull-up configuration.

Specialized Part Context

This part belongs to the PCA9543A/B family of 2-channel I2C switches. The 'AD' suffix indicates the SOIC-14 plastic small outline package. The 'PCA9543A' designation specifies the fixed slave address bits (1110), distinguishing it from the 'PCA9543B' which uses alternate address bits (1111) to resolve conflicts in larger systems.

Specialized Replacement Considerations

The PCA9543APW,118 serves as a pin-compatible alternative using the TSSOP-14 package. For systems requiring four channels, the PCA9546A series may be considered, though it lacks the specific interrupt logic found in the PCA9543A.