PCA9550D,112

Overview

The PCA9550D,112 is a 2-bit I²C bus and SMBus LED driver manufactured by NXP Semiconductors. It features two open-drain outputs capable of directly driving LEDs with a maximum sink current of 25 mA per bit and 50 mA per package. The device includes an internal oscillator providing two fully programmable blink rates for frequency and duty cycle control. It operates within a supply voltage range of 2.3 V to 5.5 V and supports clock frequencies from 0 kHz to 400 kHz. The component is housed in an SO8 surface-mount package.

Feature Summary

• Integrates an internal oscillator to generate two independently programmable blink rates without external components
• Provides hardware address selection via one pin to allow dual device operation on a single bus
• Includes low-active hardware reset and power-on reset functions to initialize registers to default states

Applications

• I²C bus applications requiring limited communication traffic
• Systems needing to release microcontroller timers for other tasks
• LED indicator control with programmable flashing patterns

Procurement Notes

Verify the specific ordering suffix to confirm the SO8 tape-and-reel packaging configuration. Confirm that the component meets RoHS compliance requirements for your target market. Ensure the design accommodates the end-of-life status if long-term availability is critical. Validate that the 2.3 V to 5.5 V operating range aligns with the system power rails.

Selection Notes

Select this component when application logic requires reducing I²C bus overhead by offloading blinking tasks from the main processor. It serves as a suitable alternative to general-purpose GPIO expanders like the PCF8574 when dedicated LED control with hardware timing is necessary. Consider the 25 mA per-bit output capability for direct LED driving without additional transistors.

Part Context

The PCA9550 belongs to the NXP I/O expander family designed specifically for LED management. Unlike standard GPIO expanders, it integrates timing hardware to manage blinking internally. This reduces the processing load on the host controller and minimizes bus contention in complex embedded systems requiring multiple visual indicators.

Replacement Considerations

No public confirmed substitute part numbers are available in the provided documentation.