PCA9557PW,118

I/o Expanders Overview

The PCA9557PW,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 an active LOW reset input, internal power-on reset, and noise filters on SCL/SDA inputs. It provides three address pins allowing up to eight devices on the bus. The component is housed in a TSSOP16 package (SOT403-1) and operates across a temperature range of -40 °C to +85 °C.

I/o Expanders Feature Summary

• Provides parallel input/output expansion for SMBus and I2C-bus applications with low current consumption.
• Includes an active LOW reset input and internal power-on reset to initialize registers and state machines.
• Features configurable polarity inversion for input pins and high-impedance open-drain output on IO0.

I/o Expanders Applications

• Parallel input/output expansion for SMBus and I2C-bus systems
• Remote control of LEDs or switches in battery-powered applications
• System interface logic for master controllers requiring additional GPIO

I/o Expanders Procurement Notes

Verify the ordering suffix '118' corresponds to the TSSOP16 package packed in Reel 13” Q1/T1 format. Confirm the manufacturer is NXP Semiconductors and check RoHS compliance status via official documentation before procurement.

I/o Expanders Selection Notes

Select this part when an 8-bit I/O expander with an external reset pin is required. Ensure the system voltage falls between 2.3 V and 5.5 V. Verify that the TSSOP16 package fits the PCB layout constraints and that the operating temperature range meets environmental requirements.

I/o Expanders Part Context

The PCA9557 series includes variants such as PCA9557BS (HVQFN16) and PCA9557D (SO16). The PW suffix specifically denotes the TSSOP16 plastic thin shrink small outline package. All variants share identical electrical characteristics and functionality, differing only in physical packaging.

I/o Expanders Replacement Considerations

Direct substitutes include PCA9557BS,118 and PCA9557D,118. These parts offer identical electrical performance but utilize HVQFN16 and SO16 packages respectively. Verify package compatibility and soldering requirements before substitution.

I/o Expanders FAQ

How is the I2C device address determined?

The address is determined by the logic levels on pins A0, A1, and A2. The base address is 0011, followed by the three address bits, resulting in addresses from 0x18 to 0x1F.

What happens to the I/O configuration upon power-up?

Upon power-up, the internal Power-On Reset initializes all registers to their default states. All channels are configured as inputs by default.

Is there an interrupt output pin?

No, the PCA9557 does not have an interrupt output pin. It relies on polling the input port register for status changes.