SIO10N268-NU

Specialized Overview

The SIO10N268 is a Super I/O controller designed for notebook and desktop systems, supporting both ISA and LPC bus architectures via jumper selection. It operates at 3.3V with 5V tolerance and complies with PC99, PC01, and ACPI 1.0 standards. The device integrates a CMOS 765B floppy disk controller, four NS16C550-compatible UARTs (one with IrDA support), a multi-mode parallel port with ChiProtect, and an X-Bus interface for memory and I/O expansion in LPC mode. It features 33 general-purpose I/O pins, LED drivers, and a watchdog timer. The component is housed in a 128-pin VTQN package.

Specialized Feature Summary

• Dual-bus architecture allowing jumper-selectable operation on either the ISA or LPC bus to facilitate design migration.
• Integrated X-Bus interface in LPC mode providing chip selects for external I/O devices and up to 2MB of flash memory emulation.
• Comprehensive peripheral set including a licensed CMOS 765B floppy controller, four high-speed serial ports, and an enhanced parallel port with EPP/ECP support.
• Support for Serial IRQ, programmable wake-up events, and system management interrupts for power management compliance.

Specialized Applications

• ISA or LPC-based notebook computer designs
• Desktop motherboard super I/O integration
• Legacy I/O expansion via X-Bus interface
• Systems requiring integrated floppy, serial, and parallel port control

Specialized Procurement Notes

Verify the specific ordering suffix against the manufacturer's current product selector guide to confirm packaging options. The datasheet indicates that the NU suffix denotes the 128-pin VTQN package. Confirm whether tape and reel availability requires a distinct TR suffix designation as noted in the product identification section. Ensure RoHS compliance documentation is obtained directly from the supplier or manufacturer website prior to procurement.

Specialized Selection Notes

Select this component when a single-chip solution is required for legacy ISA or modern LPC interfaces in portable computing platforms. The inclusion of the X-Bus interface makes it suitable for designs needing additional memory or I/O expansion beyond standard bus capabilities. Verify that the target system supports the required 3.3V logic levels and accommodates the 128-pin VTQN footprint. Consider the integrated peripherals such as the floppy controller and infrared serial port to reduce bill-of-materials complexity.

Specialized Part Context

The SIO10N268 serves as a bridge between legacy peripheral requirements and evolving system bus architectures. Originally developed by SMSC and later acquired by Microchip Technology, it allows designers to maintain BIOS compatibility while transitioning from ISA to LPC buses. The device consolidates multiple discrete logic functions into one package, reducing board space and simplifying routing for notebook manufacturers.

Specialized Replacement Considerations

Check Microchip's official obsolescence notices for direct replacements. Cross-reference pinouts and register maps if considering alternative Super I/O controllers from other vendors. Verify compatibility with existing BIOS code, as register-level differences may require firmware updates.