SCH3112-NU

Specialized Overview

The SCH3112-NU is a Super I/O controller manufactured by Microchip Technology, designed for PC99 and PC2001 compliant systems. It operates at 3.3V with a 5V tolerant SIO block and features an LPC interface supporting frequencies from 19MHz to 33MHz. The device includes 40 general-purpose I/O pins, two full-function serial ports, and a hardware monitor for voltage and temperature sensing. It integrates an 8042-compatible keyboard controller, a CMOS 765B floppy disk controller, and an enhanced parallel port. The component is housed in a 128-pin VTQFP package (14x14mm) and supports commercial operating temperatures ranging from 0°C to +70°C.

Specialized Feature Summary

• Integrated legacy functionality including an 8042-based keyboard/mouse controller, IEEE 1284 parallel port, and CMOS 765B floppy disk controller.
• Hardware monitoring capabilities with support for multiple analog voltage inputs, external thermal diodes, and programmable automatic fan control.
• Supports ACPI 2.0 compliance with sophisticated power control circuitry and programmable wake-up events.
• Includes motherboard glue logic such as reset generation, watchdog timer, and system management interrupt.

Specialized Applications

• PC99/PC2001 compliant desktop motherboards
• Industrial embedded systems requiring hardware monitoring
• Legacy I/O expansion for modern LPC-based platforms

Specialized Procurement Notes

Verify the specific ordering suffix against current Microchip documentation to confirm package type and temperature range. Confirm availability status as distribution channels may list obsolete inventory. Ensure compatibility with the target system's LPC bus configuration and voltage requirements before procurement.

Specialized Selection Notes

Select this model when two full-function serial ports are required alongside standard legacy I/O functions. Compare with the SCH3114 if four serial ports are needed or the SCH3116 for additional infrared port support. Verify that the commercial temperature range meets the environmental specifications of the intended deployment location.

Specialized Part Context

This component belongs to the SCH3112/SCH3114/SCH3116 product family of LPC IO controllers. It shares core architecture with the SCH3114 and SCH3116 but is distinguished by its provision of exactly two full-function serial ports. All variants utilize the same 128-pin VTQFP package and share common hardware monitoring and reset generation blocks.

Specialized Replacement Considerations

Publicly confirmed substitutes within the same family include the SCH3114I-NU and SCH3116I-NU. These alternatives offer increased serial port counts while maintaining pin compatibility and functional overlap. Verify software register mapping differences before implementation.