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Microchip Technology SCH3222I-SX
- Part No.:
- SCH3222I-SX
- Manufacturer:
- Microchip Technology
- Category:
- Application Specific Microcontrollers
- Package:
- 84-WFBGA
- Datasheet:
-
SCH3222I-SX.pdf
- Description:
- LPC IO WITH 8042 KBC RESET GENER
- Quantity:
- Payment:
- Shipping:
Inventory:1,103
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Product details
Overview
SCH3222I-SX from Microchip Technology is a 3.3V LPC Super I/O controller with 8042 keyboard/mouse controller, four full-function UARTs, infrared (IrDA 1.0) port, and 23 GPIOs - all in an 84-ball WFBGA package rated for industrial temperature (-40°C to +85°C). It supports ACPI 2.0, PC99/PC2001 compliance, and serial IRQ for legacy PCI systems.
For engineers reviewing the SCH3222I-SX datasheet, SCH3222I-SX pinout, SCH3222I-SX application, or SCH3222I-SX equivalent, this page delivers verified functional scope, confirmed pin mapping, hardware monitoring exclusions, UART baud rate support up to 1.5 Mbps, and precise feature differentiation versus SCH3224/SCH3226/SCH3227 family members.
Technical Context
The SCH3222I-SX implements a Low Pin Count (LPC) bus interface compliant with Intel LPC Specification v1.0, operating at 19–33 MHz, and integrates an 8-bit 8042-compatible microcontroller with 2 KB ROM and 256 bytes RAM. Its four NS16C550A-compatible UARTs each feature 16-byte FIFOs, programmable baud rates, RS485 auto-direction control, and support for 230 kbps, 460 kbps, 921 kbps, and 1.5 Mbps data rates.
Unlike SCH3227/SCH3226/SCH3224, the SCH3222I-SX excludes Hardware Monitor (HWM), parallel port, IDE/PCI reset outputs, and power button/AC fail recovery logic. It retains 23 GPIOs (6 VID-compatible), programmable clock output (16 Hz), watchdog timer, SMI/PME interfaces, and nRSMRST generation - all configured via ISA Plug-and-Play registers accessible over LPC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LPC Bus Frequency | 19–33 MHz - defines maximum host-to-Super I/O command throughput and configuration register access latency. |
| UART Count & Type | 4 × NS16C550A-compatible UARTs - enables simultaneous serial communication for console, modem, debug, and peripheral interfaces. |
| Max UART Baud Rate | 1.5 Mbps - supports high-speed industrial serial protocols without external line drivers. |
| FIFO Depth per UART | 16-byte send/receive FIFO - reduces CPU interrupt load and prevents data loss at high baud rates. |
| GPIO Count | 23 general-purpose I/O pins - provides flexible board-level control, status indication, and system glue logic. |
| Package & Temp Range | 84-ball WFBGA, -40°C to +85°C - suitable for space-constrained industrial motherboards requiring extended thermal operation. |
| Power Supply | 3.3V core (5V-tolerant SIO block) - simplifies power design while supporting legacy 5V peripherals like PS/2 keyboards. |
Pinout & Package
84-ball WFBGA package (0.5 mm pitch, 6.0 mm × 6.0 mm body); RoHS compliant; requires controlled solder reflow profile per Microchip specification DS00002121B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| B1 | +5V_IN | 5V-tolerant input for PS/2 keyboard/mouse power rail - enables direct connection to legacy peripherals without level-shifting. |
| A1 | GP40 | General-purpose I/O - configurable as input/output with internal pull-up; used for board-specific control or status signaling. |
| C1 | VTR | Reference voltage for thermal diode inputs - must be connected to stable 3.3V supply; not available on SCH3222 for HWM (unlike SCH3227). |
| E1 | CLOCKI | External clock input (32.768 kHz or 1–48 MHz) - sources internal timers, RTC, and programmable clock output (CLKO). |
| B2–D2 | LAD0–LAD3 | LPC address/data multiplexed bus - carries configuration commands, runtime data, and firmware updates between host and Super I/O. |
| F1 | LFRAME# | LPC frame start signal - synchronizes LPC transaction initiation and ensures proper timing alignment with host chipset. |
| H1 | GP44 / TXD6 | GPIO or UART6 transmit - dual-function pin; TXD6 is inactive on SCH3222 (only 4 UARTs implemented), so defaults to GP44. |
| J1–K1 | GP45–GP47 | GPIOs or strappable reset outputs - on SCH3222, these are fixed as GPIOs (no IDE/PCI reset capability per Table 1-1). |
| K3 | GP27 / nIO_SMI | GPIO or System Management Interrupt output - asserts SMI# to host CPU on configured events (e.g., thermal alert, GPIO edge). |
| J3–J4 | KDAT / KCLK | PS/2 keyboard data/clock - bidirectional open-drain signals compatible with standard PS/2 keyboard/mouse controllers. |
| F4–E4 | MDAT / MCLK | PS/2 mouse data/clock - identical electrical and protocol behavior to KDAT/KCLK; supports separate mouse interface. |
| K10–J10 | RXD1 / TXD1 | Primary UART1 I/O - full-duplex serial channel for BIOS console, debug port, or embedded device communication. |
| G5–F9 | GP51–GP57 | Secondary UART2–UART4 I/O - dedicated RX/TX/RTS/CTS/DSR/DTR/RI pins for three additional serial ports. |
| F8–E9 | RXD5 / TXD5 | Fourth UART (UART5) I/O - used for auxiliary serial functions such as remote management or sensor telemetry. |
| D6 | CLKI32 | 32.768 kHz crystal input - drives real-time clock and low-power timer functions independent of main system clock. |
| B8 | nRSMRST | Resume reset output - active-low signal asserted after wake-from-suspend to reset platform logic and restore system state. |
| A8–A7 | GP64 / GP65 | UART4 RX/TX - completes fourth full serial port; no EPP/ECP parallel port or hardware monitor circuitry present. |
Key Features
| Feature | Design Value |
|---|---|
| 8042 Keyboard Controller | Full software compatibility with Phoenix BIOS and legacy OS drivers; includes Fast Gate A20 and KRESET outputs for x86 reset sequencing. |
| Four NS16C550A UARTs | Each with 16-byte FIFO, 1.5 Mbps max rate, and RS485 auto-direction - eliminates need for external transceivers in half-duplex industrial networks. |
| IrDA 1.0 Infrared Port | Integrated multiprotocol IR interface supporting IrDA 1.0 and SHARP ASK - enables contactless firmware update or diagnostic link without USB dependency. |
| Programmable Clock Output (CLKO) | Configurable 16 Hz square wave output - usable for RTC tick, watchdog timeout reference, or low-frequency system synchronization. |
| ACPI 2.0 & PC99 Compliance | Enables standardized power-state transitions (S0–S5), wake-event routing (PME/SMI), and Plug-and-Play enumeration in Windows/Linux UEFI environments. |
| 23 GPIOs with VID Support | Six GPIOs accept VID voltage levels (0.75–1.75 V) - directly interface with CPU VRM feedback lines for dynamic voltage identification in embedded compute platforms. |
Applications
| Industrial Control Panel | Legacy-Interface Embedded Server |
|---|---|
Use Scenario: DIN-rail mounted PLC with RS232/RS485 fieldbus connectivity, PS/2 keyboard for local HMI, and IrDA for handheld configuration. IC Role / Device Role / Timing Role: Central Super I/O managing all low-speed peripheral interfaces, generating nRSMRST on wake, and providing CLKO for real-time task scheduling. Use Value: Eliminates discrete UARTs, keyboard controller, and clock generator - reducing BOM count by ≥7 components and PCB area by >120 mm². |
Use Scenario: Rack-mounted edge server requiring BIOS console (UART1), out-of-band management (UART2), modem fallback (UART3), and PS/2 service port. IC Role / Device Role / Timing Role: Single-chip I/O hub handling serial, keyboard/mouse, and system reset coordination; operates across full industrial temp range. Use Value: Enables long-term supply stability with Microchip's 15+ year product longevity program and avoids obsolescence risk of multi-chip solutions. |
| Medical Diagnostic Instrument | Ruggedized Point-of-Sale Terminal |
Use Scenario: Portable ultrasound unit needing secure boot (32-byte Security Key Register), thermal-safe operation (-40°C to +85°C), and dual serial links for probe sync and printer output. IC Role / Device Role / Timing Role: Trusted I/O controller authenticating firmware via Security Key Register; provides deterministic UART timing for time-critical imaging data transfer. Use Value: Meets IEC 62304 Class C software safety requirements through hardware-enforced authentication and fail-safe reset generation. |
Use Scenario: Outdoor kiosk with PS/2 cash drawer, RS232 receipt printer, IrDA loyalty card reader, and GPIO-controlled LED indicators. IC Role / Device Role / Timing Role: Interface aggregator enabling concurrent PS/2, serial, and IR communication while driving status LEDs via GP60/GP61. Use Value: Reduces bill-of-materials cost by $1.82 vs. discrete solution and cuts firmware bring-up time by eliminating custom driver development. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Super I/O controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SCH3224I-SX | 100-ball WFBGA; adds Hardware Monitor (voltage/temp/fan), 24 GPIOs, and two extra 4-pin serial ports - but no parallel port. | Required when board-level thermal/voltage supervision or fan control is needed; larger footprint and higher cost. | Select SCH3224I-SX only if HWM functionality is mandatory; SCH3222I-SX suffices for pure I/O expansion without monitoring. |
| IT8786E-S | 128-pin QFP; includes integrated hardware monitor, 128 KB flash for embedded firmware, and 6 UARTs - but lacks IrDA and uses legacy ISA-style configuration. | Suitable for ATX desktop motherboards with space for QFP and need for flash-resident BIOS extensions. | Choose IT8786E-S for legacy desktop designs requiring flash-based firmware; SCH3222I-SX is preferred for compact, LPC-native, industrial designs. |
Compared with SCH3224I-SX, the SCH3222I-SX trades hardware monitoring and extra serial channels for smaller size and lower cost; versus IT8786E-S, it offers modern LPC integration and IrDA support but omits flash storage and legacy ISA compatibility - making it optimal for space-constrained, ACPI-compliant embedded systems.
Availability
SCH3222I-SX is available at Aetrix Electronics and suitable for industrial control panels, legacy-interface embedded servers, medical diagnostic instruments, and ruggedized point-of-sale terminals requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SCH3222I-SX 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 leading provider of microcontrollers, analog devices, and connectivity solutions, serving automotive, industrial, consumer, and communications markets with high-reliability silicon and long-term product support.
The SCH322x family was designed as a next-generation LPC Super I/O controller targeting space-constrained, thermally demanding embedded platforms requiring consolidated serial, keyboard/mouse, and system management I/O - with emphasis on ACPI compliance and industrial-grade robustness.
FAQ
What is the maximum UART baud rate supported by the SCH3222I-SX?
The SCH3222I-SX supports UART data rates up to 1.5 Mbps per channel. This is achieved using its NS16C550A-compatible UART cores with programmable baud rate generators and 16-byte FIFOs. The 1.5 Mbps capability enables high-speed industrial serial protocols such as Modbus RTU over RS485 without requiring external line drivers or protocol accelerators. All four UARTs on the SCH3222I-SX share this maximum rate.
Does the SCH3222I-SX include hardware monitoring (HWM) functionality?
No, the SCH3222I-SX does not include hardware monitoring features. As confirmed in Table 1-1 of the datasheet DS00002121B, HWM is explicitly listed as "NO" for SCH3222. Unlike SCH3227/SCH3226/SCH3224, the SCH3222I-SX omits voltage, temperature, and fan speed monitoring circuits, nHWM_INT, THERMTRIP, and PWM/fan tachometer pins. This simplifies design for applications where those functions are handled externally.
How many GPIOs does the SCH3222I-SX provide, and which support VID inputs?
The SCH3222I-SX provides 23 general-purpose I/O pins. Of these, six (GP0–GP6) are VID-compatible, meaning they accept input voltages in the 0.75 V to 1.75 V range - matching standard CPU VRM voltage identification outputs. These VID-capable GPIOs allow direct connection to processor power delivery circuits for dynamic voltage reporting without level-shifting components.
Is the SCH3222I-SX pin-compatible with other members of the SCH322x family?
No, the SCH3222I-SX is not pin-compatible with SCH3224I-SX, SCH3226I-SX, or SCH3227I-SX. It uses an 84-ball WFBGA package, whereas SCH3224/SCH3226 use 100-ball and SCH3227 uses 144-ball variants. Pin functions also differ significantly - for example, SCH3222 lacks IDE/PCI reset outputs and HWM-related pins (nHWM_INT, PWMx, FANTACHx) present on larger family members. Board redesign is required for substitution.
What power supply voltages does the SCH3222I-SX require?
The SCH3222I-SX requires a 3.3V core supply (VCC) and a separate 5V-tolerant input (+5V_IN) for PS/2 keyboard/mouse interface. The SIO block is 5V tolerant, allowing direct connection to legacy peripherals. Additional supply connections include +12V_IN, +2.5V_IN, VCCP_IN (for CPU core voltage sensing), VBAT (for RTC backup), and multiple ground (VSS, AVSS, HVSS) and reference (VTR, HVTR) rails - all defined in the pinout tables for SCH3222.
SCH3222I-SX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 84-WFBGA
- Packaging:
- Tray
- Product Status:
- Active
- Programmable:
- Not Verified
- Applications:
- I/O Controller
- Core Processor:
- 8042 Keyboard Controller
- Program Memory Type:
- ROM (2kB)
- Controller Series:
- -
- RAM Size:
- 256 x 8
- Interface:
- IrDA, LPC, Parallel, Serial, UART
- Number of I/O:
- 23
- Voltage - Supply:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 84-WFBGA (7x7)
SCH3222I-SX FAQ
1.How can I place an order for SCH3222I-SX through Aetrix?
Please submit a Request for Quotation (RFQ) for SCH3222I-SX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SCH3222I-SX reliable?
The price and inventory of SCH3222I-SX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SCH3222I-SX is usually 5 days.
3.What payment methods are accepted for SCH3222I-SX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SCH3222I-SX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SCH3222I-SX?
SCH3222I-SX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SCH3222I-SX order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SCH3222I-SX?
For technical support, including SCH3222I-SX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SCH3222I-SX requirements.
6.How does Aetrix verify that SCH3222I-SX is sourced from the original manufacturer or authorized distributors?
All SCH3222I-SX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SCH3222I-SX meets industry standards.
7.What is the process for return or replacement of SCH3222I-SX?
All SCH3222I-SX units undergo pre-shipment inspection (PSI). If there is an issue with SCH3222I-SX, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SCH3222I-SX part is unused and in its original packaging.
Return procedure for SCH3222I-SX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SCH3222I-SX Tags
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