Texas Instruments

PCF8575CDB

PCF8575CDB Description

The PCF8575CDB by Texas Instruments is a 16-bit I²C/SMBus I/O expander designed for surface-mount applications, packaged in a 24-SSOP tube. Operating within a 4.5V to 5.5V supply range, it supports a 400 kHz clock frequency, making it suitable for high-speed communication in embedded systems. With open-drain outputs, it offers flexible interfacing for driving LEDs, relays, or other peripherals. The device includes an interrupt output for efficient event-driven processing and features Power-On Reset (POR) for reliable initialization. Though marked obsolete, it remains a robust choice for legacy designs requiring ROHS3-compliant, low-power I/O expansion.

PCF8575CDB Features

• 16 I/O Ports: Configurable as inputs or outputs with 10mA sink/25mA source capability per pin.
• I²C/SMBus Interface: Compatible with standard protocols at 400 kHz, enabling fast data transfer.
• Interrupt Output: Reduces polling overhead by signaling host MCU on input state changes.
• Open-Drain Outputs: Allows direct drive of LEDs or other low-voltage devices without external pull-ups.
• Power-On Reset (POR): Ensures stable startup conditions, critical for industrial applications.
• Wide Voltage Range (4.5V–5.5V): Integrates seamlessly with 5V systems.
• Surface-Mount (SSOP-24): Compact footprint for space-constrained PCB designs.

PCF8575CDB Applications

• Industrial Control Systems: Expands GPIO for PLCs or sensor arrays with interrupt-driven responsiveness.
• Consumer Electronics: Drives keypad matrices or LED displays in appliances.
• Embedded Systems: Adds I/O capacity to microcontrollers (e.g., Arduino, Raspberry Pi) via I²C.
• Automotive Interfaces: Supports low-voltage peripheral control in legacy vehicle electronics.
• Test Equipment: Facilitates modular I/O expansion for diagnostic tools.

Conclusion of PCF8575CDB

The PCF8575CDB excels in high-speed, low-power I/O expansion with its interrupt capability and open-drain flexibility. While obsolete, its robust design and compliance with modern standards (ROHS3, REACH) make it viable for legacy upgrades or niche applications. Engineers valuing ease of integration and reliability in 5V systems will find it a pragmatic solution despite newer alternatives.

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