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Microchip Technology SCH3221I-7U
- Part No.:
- SCH3221I-7U
- Manufacturer:
- Microchip Technology
- Category:
- Specialized
- Package:
- 64-WFBGA
- Datasheet:
-
SCH3221I-7U.pdf
- Description:
- IC INTFACE SPECIALIZED 64WFBGA
- Quantity:
- Payment:
- Shipping:
Inventory:2,804
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Product details
Overview
SCH3221I-7U from Microchip Technology is a 3.3V, 5V-tolerant LPC-based Super I/O controller featuring four NS16550-compatible UARTs with 16-byte FIFOs, dual IR ports supporting IrDA v1.2 (4 Mbps), 33 GPIOs, programmable watchdog timer, and two LED drivers - deployed in industrial PC motherboards for legacy serial and infrared peripheral connectivity.
For engineers reviewing the SCH3221I-7U datasheet, SCH3221I-7U pinout, SCH3221I-7U application, or SCH3221I-7U equivalent, key selection criteria include LPC bus compliance, 460 kbps UART throughput, VTR-powered wake-up capability via RI/GPIO/WDT, and 64-ball WFBGA package thermal and layout constraints.
Technical Context
The SCH3221I-7U implements a Low Pin Count (LPC) host interface compliant with Intel LPC Specification Rev 1.0, supporting Serial IRQ, ACPI-compliant power management, and System Management Interrupt (SMI) generation. Its runtime register architecture enables dynamic configuration of UART base addresses (480 options), IRQ assignments (15 per function), and PME sources.
It integrates dual IR transceivers (IRTX2/IRRX2 and IRTX/IRRX on UART2, plus IRRX3), consumer IR support, and hardware-level wake-up logic powered by VTR - enabling persistent monitoring of ring indicators (nRI1–nRI4), GPIOs (GP11–GP57), and watchdog timeout while VCC is off.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 3.3 V nominal; non-LPC pins 5V tolerant (max 5.5 V); LPC pins strictly 3.3 V only |
| UART Count & Type | 4 × NS16550-compatible UARTs; each with 16-byte TX/RX FIFOs and full 8-pin modem control |
| Max Baud Rate | 460 kbps - supports high-speed serial communication without CPU overhead |
| IR Support | IrDA v1.2 (4 Mbps), HPSIR, ASKIR, and Consumer IR; 2 dedicated IR ports with shared GPIO resources |
| GPIO Count | 33 general-purpose I/O pins - including 22 with VTR-powered wake-up capability for S3/S4 states |
| Package | 64-ball WFBGA (5.5 mm × 5.5 mm, 0.5 mm pitch), RoHS compliant, industrial temperature range (−40°C to +85°C) |
| Power Domains | Dual-rail: VCC (3.3 V main) and VTR (3.3 V trickle supply); enables wake-on-RI/GPIO/WDT during VCC-off states |
Pinout & Package
64-ball WFBGA package with 0.5 mm pitch; ball grid layout optimized for low-inductance LPC signaling and thermal dissipation in embedded motherboard applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LAD[3:0] | LPC multiplexed address/data bus | Carries command, address, and data over shared 4-bit bidirectional lines; requires precise timing per LPC spec |
| LFRAME# | LPC frame signal | Indicates start/end of LPC cycle; active-low, synchronized to PCI_CLK |
| IO_PME# | Power Management Event output | Open-drain, VTR-powered active-low signal asserting wake event to chipset during S3/S4 sleep states |
| GP57/nDTR2 | GPIO / Data Terminal Ready 2 | Must be externally pulled low at power-on to disable LPC memory cycle handling and ensure bus stability |
| CLKI32 | 32.768 kHz standby clock input | Optional external crystal input for WDT and LED blink timing; if unused, must be grounded and CR1E[0] set to '1' |
| nLED1 / nLED2 | Dual LED drivers | nLED1 powered by VCC (active only under main power); nLED2 powered by VTR (blinks during standby) |
Key Features
| Feature | Design Value |
|---|---|
| ACPI & PC99/PC2001 Compliance | Enables seamless integration into legacy and modern BIOS/UEFI firmware stacks with standardized power-state transitions |
| Programmable Wake-up Sources | Supports wake-from-sleep via UART ring indicators (nRI1–nRI4), 22 GPIOs, or watchdog timeout - all functional under VTR-only power |
| IrDA v1.2 + Consumer IR | Hardware-accelerated infrared protocol engine eliminates CPU polling; supports bidirectional 4 Mbps data transfer and remote control decoding |
| Four Full-Function UARTs | Each UART provides complete modem handshaking (RTS/CTS/DTR/DSR/DCD/RI), 16-byte FIFOs, and independent IRQ/base address assignment |
| VTR-Powered Runtime Registers | WDT, LED, PME, SMI, and GPIO data registers remain accessible and functional during VCC-off states for reliable wake-event management |
Applications
| Industrial Embedded Control Panel | Retail Point-of-Sale Terminal |
|---|---|
|
Use Scenario: Legacy RS-232 barcode scanners, receipt printers, and magnetic stripe readers require simultaneous high-speed serial interfaces with robust ESD-tolerant I/O. IC Role / Device Role / Timing Role: SCH3221I-7U serves as primary Super I/O hub managing four concurrent UART channels, GPIO-controlled status LEDs, and watchdog supervision - all coordinated via LPC bus under ACPI power states. Use Value: Eliminates need for discrete UARTs and GPIO expanders; 460 kbps throughput ensures scanner decode latency < 1 ms; VTR-powered wake allows instant resume from deep sleep on scanner trigger. |
Use Scenario: Compact POS systems integrate serial peripherals (cash drawer, pole display, PIN pad) alongside IR-based customer-facing remotes and staff badge readers. IC Role / Device Role / Timing Role: SCH3221I-7U provides dual IR transceivers (IRTX2/IRRX2 + IRRX3) and four UARTs in single WFBGA package - reducing PCB area and BOM count versus multi-chip solutions. Use Value: IrDA v1.2 support enables secure 4 Mbps firmware updates to peripherals; GPIO-controlled cash drawer latch and LED indicators simplify firmware integration; 64-ball WFBGA fits tight motherboard layouts. |
| Medical Diagnostic Equipment | Network Appliance Console Server |
|
Use Scenario: Ultrasound and imaging devices require fail-safe serial console access, real-time watchdog reset, and IR-based service mode activation without host CPU intervention. IC Role / Device Role / Timing Role: SCH3221I-7U delivers independent watchdog timer with VTR-backed timeout, dedicated UART1 for BIOS debug, and GP13/nLED1 for visual fault indication - all operational during system boot or crash recovery. Use Value: Watchdog reset occurs within 16 ms of timeout; nLED1 blinks diagnostic patterns even during VCC brownout; RI-driven wake enables technician IR commands before OS load. |
Use Scenario: Rack-mounted switches and firewalls use serial console servers to manage dozens of network devices via RS-232; reliability and remote serviceability are critical. IC Role / Device Role / Timing Role: SCH3221I-7U acts as console concentrator with four isolated UARTs, GPIO-mapped relay controls for power cycling, and PME-triggered alerting via nIO_PME# to BMC. Use Value: Each UART supports independent 480 base address options and 15 IRQs - enabling conflict-free coexistence with other LPC devices; VTR-powered GPIO monitoring ensures console availability during host power loss. |
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 |
|---|---|---|---|
| ITE IT8786E | 3.3V LPC Super I/O with 3 UARTs, no IR support, 128-pin QFP package | Lacks IrDA v1.2 and second IR port; larger footprint limits space-constrained designs | Select when IR functionality is unnecessary and board layout accommodates QFP |
| Nuvoton NCT6776D | 3.3V LPC Super I/O with 4 UARTs, no IR, integrated hardware monitor, 128-pin LQFP | Includes thermal/voltage monitoring but omits infrared transceivers and consumer IR decoding | Prefer when system health telemetry is prioritized over IR peripheral support |
Compared with ITE IT8786E and Nuvoton NCT6776D, the SCH3221I-7U uniquely delivers dual IR transceivers with IrDA v1.2 (4 Mbps) and consumer IR in a compact 64-ball WFBGA - making it the only option for space-limited industrial PCs requiring both high-speed serial and infrared connectivity with VTR-powered wake.
Availability
SCH3221I-7U is available at Aetrix Electronics and suitable for industrial embedded control panels, retail point-of-sale terminals, medical diagnostic equipment, and network appliance console servers requiring stable component supply across extended product lifecycles.
Supply support for SCH3221I-7U 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 is a global semiconductor company specializing in microcontrollers, analog devices, and interface ICs - with a strong heritage in PC I/O and embedded control solutions.
The SCH3221I-7U belongs to Microchip's legacy Super I/O product line, designed specifically for industrial and commercial PC platforms requiring backward-compatible serial, IR, and GPIO expansion with ACPI-compliant power management.
FAQ
What is the maximum baud rate supported by the SCH3221I-7U UARTs?
The SCH3221I-7U supports up to 460 kbps per UART, enabled by its NS16550-compatible design with programmable baud rate generators. This rate is achievable using the internal 14.318 MHz clock source and appropriate divisor settings in the DLL/DLM registers. The SCH3221I-7U datasheet confirms this limit applies to all four UARTs under standard operating conditions.
Does the SCH3221I-7U support wake-up from S3/S4 sleep states?
Yes, the SCH3221I-7U supports wake-up from S3 (suspend-to-RAM) and S4 (hibernate) states via its VTR-powered PME logic. Valid wake sources include nRI1–nRI4, 22 designated GPIOs (e.g., GP11–GP13, GP20–GP23), and the watchdog timer - all monitored while VCC is off, provided VTR remains active at ≥3.0 V.
Is the SCH3221I-7U pin-compatible with earlier SMSC Super I/O devices?
No, the SCH3221I-7U is not pin-compatible with prior SMSC Super I/O controllers such as the SCH3112 or SCH3114. It uses a unique 64-ball WFBGA footprint and revised LPC signal mapping. Migration requires PCB redesign and firmware register reconfiguration due to differences in base address handling, GPIO grouping, and IR pin assignments.
What is the purpose of the GP57/nDTR2 pin requirement in the SCH3221I-7U?
The GP57/nDTR2 pin on the SCH3221I-7U must be externally pulled low at power-on to disable LPC memory cycle handling - a mandatory strap per datasheet Note 3-12. Failure to do so risks unpredictable LPC bus behavior, excessive current draw, and potential damage. This requirement is specific to the SCH3221I-7U and differs from other Microchip Super I/O variants.
Can the SCH3221I-7U operate without an external 32.768 kHz crystal?
Yes, the SCH3221I-7U can operate without an external 32.768 kHz crystal by configuring CR1E[0] = '1' to derive the 32 kHz clock internally from the 14.318 MHz input. However, WDT timeout accuracy and LED blink timing will then depend on the stability of the main clock; for guaranteed ±20 ppm timing, an external crystal on CLKI32 is required - and CLKI32 must be grounded if unused.
SCH3221I-7U Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 64-WFBGA
- Packaging:
- Tray
- Product Status:
- Active
- Applications:
- I/O Controller
- Interface:
- -
- Voltage - Supply:
- 3.3V
- Supplier Device Package:
- 64-WFBGA (6x6)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
SCH3221I-7U FAQ
1.How can I place an order for SCH3221I-7U through Aetrix?
Please submit a Request for Quotation (RFQ) for SCH3221I-7U 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 SCH3221I-7U reliable?
The price and inventory of SCH3221I-7U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SCH3221I-7U is usually 5 days.
3.What payment methods are accepted for SCH3221I-7U?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SCH3221I-7U transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SCH3221I-7U?
SCH3221I-7U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SCH3221I-7U 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 SCH3221I-7U?
For technical support, including SCH3221I-7U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SCH3221I-7U requirements.
6.How does Aetrix verify that SCH3221I-7U is sourced from the original manufacturer or authorized distributors?
All SCH3221I-7U 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 SCH3221I-7U meets industry standards.
7.What is the process for return or replacement of SCH3221I-7U?
All SCH3221I-7U units undergo pre-shipment inspection (PSI). If there is an issue with SCH3221I-7U, 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 SCH3221I-7U part is unused and in its original packaging.
Return procedure for SCH3221I-7U:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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