PCA9557D/DG,118

I/o Expanders Overview

The PCA9557D/DG,118 is an NXP USA Inc. silicon CMOS circuit providing parallel input/output expansion for SMBus and I2C-bus applications. It features an 8-bit input port register, an 8-bit output port register, and a dedicated active LOW reset input. The device operates within a power supply voltage range of 2.3 V to 5.5 V and supports clock frequencies from 0 kHz to 400 kHz. It includes internal power-on reset logic, noise filters on SCL/SDA inputs, and high-impedance open-drain outputs on IO0. ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per JESD22-C101.

I/o Expanders Feature Summary

• Provides 8 general-purpose input/output expander/collector channels with configurable direction via the configuration register.
• Features an active LOW reset input that initializes registers and the I2C/SMBus state machine without de-powering the part.
• Includes polarity inversion capabilities for input pins and hardware-selectable address pins allowing up to 8 devices on the bus.

I/o Expanders Applications

• Parallel input/output expansion for SMBus and I2C-bus systems
• Low standby current applications requiring minimal power consumption
• Systems requiring hardware-level reset initialization independent of power cycling

I/o Expanders Procurement Notes

Verify the specific ordering suffix

I/o Expanders Selection Notes

Select this component when an 8-bit I/O expander with a dedicated hardware reset pin is required for I2C or SMBus architectures. Ensure the design accommodates the 2.3 V to 5.5 V operating voltage range and utilizes external pull-up resistors for the SDA/SCL lines and address pins, as no internal pull-ups are incorporated.

I/o Expanders Part Context

The PCA9557 serves as a lower voltage, higher performance migration path for the PCA9556. It belongs to the PCA9557 series of 8-bit I2C-bus and SMBus I/O ports. The device is available in SO16, TSSOP16, and HVQFN16 packages, designed to replace legacy expanders while offering enhanced ESD protection and glitch-free power-up behavior.

I/o Expanders Replacement Considerations

Public confirmed substitute: PCA9556. Verify package compatibility (SO16) and electrical characteristics against the target application requirements before substitution.