Texas Instruments

PCA9535PW

PCA9535PW Description

The PCA9535PW from Texas Instruments is a 16-bit I²C/SMBus I/O expander designed for 2.3V to 5.5V systems, offering flexible input/output (I/O) port expansion with 400 kHz clock frequency support. Housed in a 24-pin TSSOP package, this IC is ideal for space-constrained applications requiring bidirectional voltage-level translation. Though marked Obsolete, it remains a reliable choice for legacy designs due to its power-on reset (POR), interrupt output, and low standby current consumption.

PCA9535PW Features

• 16 configurable I/O pins with 10mA source/25mA sink current capability, enabling direct LED driving or logic interfacing.
• I²C/SMBus-compatible interface (up to 400 kHz) for efficient communication with microcontrollers.
• Wide voltage range (2.3V–5.5V), supporting mixed-voltage systems without external level shifters.
• Interrupt output pin for efficient event-driven designs, reducing polling overhead.
• Power-on reset (POR) ensures stable initialization, critical for robust system startups.
• RoHS3 compliant and REACH unaffected, meeting environmental regulations.

PCA9535PW Applications

• Industrial control systems: Expands I/O for PLCs, sensors, and actuators.
• Consumer electronics: Drives LEDs, keypads, or display backlighting in smart home devices.
• Embedded systems: Interfaces with low-voltage MCUs in IoT edge nodes.
• Legacy designs: Replaces discrete logic in cost-sensitive, low-complexity circuits.

Conclusion of PCA9535PW

The PCA9535PW excels in I/O expansion with its high current drive, interrupt efficiency, and wide voltage compatibility. While obsolete, its robust feature set—including POR and SMBus support—makes it a pragmatic choice for retrofit designs or systems prioritizing proven reliability. Engineers should evaluate modern alternatives for new designs but can leverage this IC’s simplicity and performance in legacy upgrades.