PCA9557D,118

I/o Expanders Overview

The PCA9557D,118 is an 8-bit I2C-bus and SMBus I/O expander manufactured by NXP Semiconductors. It operates within a supply voltage range of 2.3 V to 5.5 V and supports clock frequencies up to 400 kHz. The device features eight general-purpose I/O pins (IO0-IO7) with configurable input/output directions via a configuration register. IO0 provides a high-impedance open-drain output, while IO1 through IO7 are push-pull outputs. It includes an active LOW reset input, polarity inversion registers, and internal power-on reset logic. The component is housed in a 16-lead SOIC package (SOT109-1) and functions across an ambient temperature range of -40 °C to +85 °C.

I/o Expanders Feature Summary

• Provides parallel input/output expansion for SMBus and I2C-bus applications
• Features an active LOW reset input for system initialization without power cycling
• Includes noise filters on SCL and SDA inputs to enhance signal integrity
• Supports hardware-selectable slave addresses allowing up to eight devices on the bus

I/o Expanders Applications

• Remote I/O expansion in industrial automation systems
• Process control interfaces requiring low standby current
• Battery-powered portable devices needing efficient GPIO management

I/o Expanders Procurement Notes

Verify the specific ordering suffix

I/o Expanders Selection Notes

Select this variant when a standard plastic small outline package is required for PCB layout constraints. Ensure external pull-up resistors are provided for SDA, SCL, and address pins as internal pull-ups are not incorporated. Confirm that the 5 V tolerant inputs match the host controller's logic levels.

I/o Expanders Part Context

This part belongs to the PCA9557 family of 8-bit I/O expanders. It serves as a migration path from the PCA9556, offering lower voltage operation and higher performance. The D suffix specifically denotes the SO16 package format, distinguishing it from TSSOP or HVQFN variants within the same functional series.

I/o Expanders Replacement Considerations

PCA9557D,112 is a tube-packaged alternative from NXP. Texas Instruments offers the PCA9557DB in an SSOP-16 package with similar functionality but different voltage limits.