Microchip Technology SCH3227I-SZ-TR

Overview

SCH3227I-SZ-TR from Microchip Technology is a 3.3V LPC Super I/O controller with 5V-tolerant SIO block, integrated 8042 keyboard controller, four full-function UARTs, infrared port, hardware monitoring, and 40 GPIOs - deployed in industrial embedded motherboards for legacy I/O consolidation and power management.

For engineers reviewing the SCH3227I-SZ-TR datasheet, SCH3227I-SZ-TR pinout, SCH3227I-SZ-TR application, or SCH3227I-SZ-TR equivalent, key selection criteria include LPC bus timing (19–33 MHz), hardware monitor accuracy (±1.5°C remote diode sensing), IDE/PCI reset buffer availability, strap-configurable feature set (STRAPOPT=0/1), and WFBGA-144 package compatibility with thermal diode inputs and PWM fan control.

Technical Context

The SCH3227I-SZ-TR implements an LPC interface compliant with Intel Low Pin Count Specification Rev 1.0, supporting 19–33 MHz bus frequencies and Serial IRQ signaling. It integrates an 8-bit 8042-compatible microcontroller with 2 KB ROM and 256 bytes RAM, managing keyboard/mouse via dedicated open-drain outputs and Port 92 support.

Hardware monitoring includes four analog voltage inputs (+2.5V, +5V, +12V, Vccp), internal VCC/VTR/VBAT sensing, dual remote thermal diode interfaces (REMOTE1±/REMOTE2±), three FANTACH inputs, and three PWM outputs (PWM1–PWM3) with programmable fan control logic and nHWM_INT alert assertion.

Key Specifications

Pinout & Package

Package: 144-ball WFBGA (6.0 × 6.0 mm, 0.5 mm pitch), RoHS-compliant, with exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Super I/O controller applications.

Compared with SCH3226I-SZ-TR, the SCH3227I-SZ-TR adds hardware monitoring, IDE/PCI reset buffers, and parallel port - enabling full-featured legacy I/O consolidation. Versus IT8786E-S, it trades analog channel count for LPC efficiency and WFBGA footprint, prioritizing integration density over monitoring granularity.

Availability

SCH3227I-SZ-TR is available at Aetrix Electronics and suitable for industrial control panels, medical diagnostic equipment, ruggedized network appliances, and legacy industrial PC upgrades requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SCH3227I-SZ-TR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a global semiconductor manufacturer specializing in microcontrollers, analog devices, and interface ICs, with deep expertise in embedded control and system-level integration.

The SCH3227 product line delivers highly integrated Super I/O solutions targeting x86-based industrial and embedded motherboards needing consolidated legacy I/O, hardware monitoring, and ACPI-compliant power management.

FAQ

What is the function of the STRAPOPT pin on the SCH3227I-SZ-TR?

The STRAPOPT pin (Ball K13) configures the SCH3227I-SZ-TR's feature set and Device ID register. When strapped to VTR, it enables SCH3114-compatible functionality and Device ID 0x7F; when strapped to VSS, it selects SCH3116 mode and Device ID 0x7D. This setting determines whether IDE/PCI reset outputs or additional 4-pin serial ports are active - a hardware-level configuration that must be fixed at board design time. The SCH3227I-SZ-TR requires correct STRAPOPT strapping for functional integrity.

Does the SCH3227I-SZ-TR support RS485 communication natively?

Yes, the SCH3227I-SZ-TR supports RS485 Auto Direction Control mode in its UART peripherals. When enabled, the nRTS signal is automatically driven based on transmit FIFO status - asserted when the output buffer loads and deasserted when empty - eliminating external direction-control logic. This feature applies to all four full-function UARTs and is configured via runtime registers. The SCH3227I-SZ-TR does not include RS485 transceivers; external drivers remain required.

How many thermal diode inputs does the SCH3227I-SZ-TR support, and what is their accuracy?

The SCH3227I-SZ-TR supports two remote thermal diode inputs (REMOTE1± and REMOTE2±) plus one internal ambient sensor. Remote diode measurements achieve ±1.5°C accuracy across the −40°C to +85°C operating range, as specified in DS00002121B. These inputs connect directly to CPU/GPU thermal diodes and feed into the hardware monitor block, enabling automatic fan speed adjustment and nHWM_INT assertion on thermal violation. The SCH3227I-SZ-TR does not require external calibration for this accuracy.

Is the SCH3227I-SZ-TR compatible with ACPI 2.0 and PC2001 standards?

Yes, the SCH3227I-SZ-TR is explicitly designed to comply with both ACPI 2.0 and PC2001 specifications. It implements System Management Interrupt (SMI), Programmable Wake-up Event (PME), Serial IRQ, and power-state transition logic required for OS-directed power management. Its register set conforms to ISA Plug-and-Play v1.0a, and its LPC interface meets Intel's Low Pin Count specification. This compliance ensures seamless integration with standard BIOS implementations and Windows/Linux power management stacks - a core requirement validated for the SCH3227I-SZ-TR.

What is the purpose of the Security Key Register in the SCH3227I-SZ-TR?

The SCH3227I-SZ-TR includes a 32-byte battery-backed Security Key Register used for device authentication and platform identity binding. It retains values across power cycles when VBAT is supplied, enabling secure boot verification, firmware signature validation, and anti-cloning measures. Access is restricted via configuration lock bits, and the register is write-protected after initial programming unless unlocked via specific key sequences. This feature is integral to the SCH3227I-SZ-TR's security architecture and cannot be emulated by software alone.