My Inquiry
My Account
Microchip Technology LPC47S457-NS
- Part No.:
- LPC47S457-NS
- Manufacturer:
- Microchip Technology
- Category:
- Specialized
- Package:
- 128-BFQFP
- Datasheet:
-
LPC47S457-NS.pdf
- Description:
- IC INTERFACE SPECIALIZED 128QFP
- Quantity:
- Payment:
- Shipping:
Inventory:2,341
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LPC47S457-NS from SMSC is a Super I/O controller integrating floppy disk, dual UARTs, parallel port, 8042 keyboard controller, SMBus, RTC, fan control, and GPIOs in a single 128-pin QFP package. It operates at 3.3 V (5 V tolerant), supports ACPI 2.0 and PC2001, and delivers full IBM-compatible FDC functionality with 16-byte FIFO, EPP/ECP parallel modes, and NS16C550A-compatible UARTs - deployed in legacy industrial PCs and embedded x86 platforms requiring consolidated I/O.
For engineers reviewing the LPC47S457-NS datasheet, LPC47S457-NS pinout, LPC47S457-NS application, or LPC47S457-NS equivalent, key selection considerations include ISA/LPC host interface compatibility, real-time clock battery-backed RAM configuration, X-Bus expandability for LCD controllers, and PME/SMI event routing via dedicated IO_PME# and IO_SMI# pins.
Technical Context
The LPC47S457-NS implements a unified LPC bus interface compliant with Intel's Low Pin Count specification, supporting 8-bit I/O and DMA transfers with serial IRQ arbitration. Its integrated 8042 keyboard controller includes 2 kB ROM and 256 B RAM, enabling self-contained keyboard/mouse handling without external firmware.
It embeds dual NS16C550A-compatible UARTs with 16-byte send/receive FIFOs, programmable baud rates up to 460 kbps, and IrDA 1.0/HP-SIR support. The floppy controller is licensed CMOS 765B core, software- and register-compatible with SMSC's 82077AA derivative, featuring vertical recording format support and overrun/underrun detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 3.3 V nominal, 5 V tolerant I/O - enables direct interfacing with legacy 5 V peripherals without level shifters. |
| Floppy Controller | 2-channel 2.88 MB FDC with 16-byte FIFO, vertical recording support, and 100% IBM compatibility - ensures reliable boot and data access on legacy drives. |
| UARTs | Two NS16C550A-compatible UARTs with 16-byte FIFOs and IrDA 1.0/HP-SIR - supports high-speed serial diagnostics and infrared communication. |
| Parallel Port | Multi-mode: IBM PC/XT/AT, EPP 1.7/1.9, IEEE 1284 ECP - enables bidirectional printer, scanner, and diagnostic tool connectivity. |
| RTC & Memory | MC146818/DS1287-compatible RTC with 256 B battery-backed CMOS RAM (dual 128 B banks) - retains time, alarms, and system configuration across power cycles. |
| GPIO Count | 55 general-purpose I/O pins with PME/SMI interrupt capability and edge-triggered sensing - provides flexible board-level control and monitoring. |
| Package | 128-pin QFP (14 × 20 mm, 0.4 mm pitch) - standard footprint compatible with automated SMT assembly and thermal management in compact PCB layouts. |
Pinout & Package
Package: 128-pin Quad Flat Package (QFP), lead-free RoHS-compliant, with Phoenix 42i Keyboard BIOS firmware preloaded. Thermal pad exposed on underside per datasheet mechanical drawings.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IO_PME# | Power Management Event output | Asserts active-low signal to wake host CPU from sleep states - critical for ACPI S3/S4 resume triggering. |
| IO_SMI# | System Management Interrupt input | Triggers SMM handler for secure firmware operations like BIOS updates or hardware lockdown. |
| LCLK | LPC clock input | Accepts 33 MHz clock from host chipset - synchronizes all LPC bus transactions including configuration and data reads. |
| LRESET# | LPC reset input | Resets internal logic and registers when asserted low - required for cold boot initialization and error recovery. |
| VCC | Main power supply | 3.3 V supply for core logic; decoupling required per datasheet layout guidelines to ensure noise immunity. |
| Vbat | Battery backup supply | Connects to coin cell to maintain RTC time and CMOS RAM during main power loss - <1 μA standby current enables multi-year retention. |
Key Features
| Feature | Design Value |
|---|---|
| X-Bus Interface | Supports up to four external I/O components (e.g., LCD controllers) with configurable address mapping - extends system I/O without additional host resources. |
| Programmable Wakeup Events | Configurable PME sources include RTC alarm, keyboard activity, and GPIO edges - enables selective, low-power wake-up without polling. |
| Fan Control Subsystem | One PWM output for speed regulation and one tachometer input for RPM feedback - provides closed-loop thermal management for passive-cooled systems. |
| ACPI 2.0 Compliance | Full implementation of Gx/Sx power states, SCI routing, and PM1/PM2 control registers - ensures interoperability with Windows and Linux power management stacks. |
| ChiProtect Circuitry | Integrated protection on parallel port pins against voltage transients during printer power-on - eliminates need for external TVS diodes in printer interface designs. |
Applications
| Industrial Control Panel | Legacy Embedded PC |
|---|---|
Use Scenario: Fan-cooled HMI panel with serial debug port, parallel-connected barcode scanner, and RTC-based job scheduling. IC Role / Device Role / Timing Role: Central I/O hub managing UART diagnostics, EPP-scanner data capture, and real-time job triggers via RTC alarm. Use Value: Reduces BOM count by consolidating FDC, UARTs, parallel port, RTC, and fan control - simplifies design and improves long-term component availability. | Use Scenario: x86-based medical device requiring BIOS keyboard support, floppy-based firmware update, and IrDA patient data transfer. IC Role / Device Role / Timing Role: 8042 keyboard controller + NS16C550A UART + IR transceiver + FDC - enables legacy serviceability and regulatory-compliant field updates. Use Value: Maintains full IBM PC compatibility while delivering IrDA 1.0 and HP-SIR support - satisfies FDA-required update traceability and diagnostic accessibility. |
| POS Terminal | Test & Measurement Rack |
Use Scenario: Compact retail terminal with ECP parallel receipt printer, dual serial payment peripherals, and battery-backed audit log timestamping. IC Role / Device Role / Timing Role: Parallel port controller + dual UARTs + RTC - handles concurrent printer spooling, EMV reader comms, and secure time-stamped transaction logging. Use Value: 256 B battery-backed RAM stores last 100 transaction timestamps even during AC failure - meets PCI-DSS audit trail continuity requirements. | Use Scenario: Automated test rack with GPIO-controlled DUT power sequencing, fan-cooled enclosure, and serial console for script-based calibration. IC Role / Device Role / Timing Role: GPIO supervisor + fan tachometer monitor + UART console - orchestrates safe power-up/down sequences and thermal safety shutdown. Use Value: 55 GPIOs with either-edge interrupt enable precise timing of stimulus/response events - reduces need for external CPLD logic in timing-critical test fixtures. |
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 |
|---|---|---|---|
| Nuvoton NCT6776D | Modern 128-pin LQFP, native LPC 1.1, no floppy controller, added hardware watchdog and voltage monitoring - lacks FDC but adds precision ADC and thermal diode support. | Targeted at modern embedded systems where floppy is obsolete but multi-rail voltage supervision is required - not suitable for legacy FDC-dependent BIOS environments. | Select when upgrading from LPC47S457-NS in non-floppy applications needing enhanced power rail monitoring and faster boot times. |
| ITE IT8728F | 128-pin QFP, supports floppy (CMOS 765B), dual UARTs, ECP/EPP, RTC, and 54 GPIOs - similar feature set but uses different SMBus slave addressing and lacks X-Bus interface. | Compatible in pinout and basic I/O function, but requires BIOS/firmware reconfiguration for SMBus2 register mapping and GPIO initialization sequence. | Consider for drop-in replacement only after validating SMBus2 device disable register behavior and X-Bus absence in target system architecture. |
Compared with LPC47S457-NS, the NCT6776D removes floppy support to add precision analog monitoring, while the IT8728F retains FDC compatibility but omits X-Bus expansion - both require firmware adaptation, and neither offers identical PME/SMI routing or Phoenix 42i BIOS integration.
Availability
LPC47S457-NS is available at Aetrix Electronics and suitable for industrial control panels, legacy embedded PCs, POS terminals, and test & measurement racks requiring stable component supply and long-life obsolescence management.
Supply support for LPC47S457-NS 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
SMSC (Standard Microsystems Corporation) was a fabless semiconductor company specializing in connectivity, embedded I/O, and mixed-signal solutions before its acquisition by Microchip Technology in 2012.
The LPC47S45x family was designed as a high-integration Super I/O solution for x86-based industrial and embedded platforms requiring consolidated legacy I/O, ACPI-compliant power management, and BIOS firmware co-location - specifically targeting long-lifecycle PC/AT-compatible systems.
FAQ
What is the primary function of the LPC47S457-NS in an x86 system?
The LPC47S457-NS serves as a Super I/O controller that integrates legacy peripheral interfaces - including floppy disk, dual UARTs, parallel port, 8042 keyboard controller, RTC, SMBus, and GPIOs - onto a single chip connected via the LPC bus. It replaces discrete I/O chips in industrial PCs and embedded x86 platforms, reducing board complexity while maintaining full IBM PC compatibility and ACPI 2.0 compliance. The LPC47S457-NS is essential for boot firmware execution, hardware initialization, and runtime peripheral management.
Does the LPC47S457-NS support floppy disk drives beyond standard 1.44 MB capacity?
Yes, the LPC47S457-NS supports 2.88 MB SuperDisk drives via its licensed CMOS 765B floppy disk controller core. It implements vertical recording format support, 16-byte data FIFO, and full overrun/underrun detection - all required for reliable high-density floppy operation. The controller is software- and register-compatible with SMSC's 82077AA derivative and maintains 100% IBM compatibility, enabling use with standard BIOS drivers and OS-level FDC abstractions.
How does the LPC47S457-NS handle real-time clock battery backup?
The LPC47S457-NS includes a MC146818- and DS1287-compatible RTC with 256 bytes of battery-backed CMOS RAM organized in two 128-byte banks. The Vbat pin accepts a 3 V coin cell to maintain timekeeping and RAM contents during main power loss. Its standby current is specified at <1 μA typical, enabling multi-year retention. The RTC supports 12/24-hour formats, daily and 30-day alarms, and binary/BCD encoding - all accessible via standard I/O port 70h/71h sequences.
Can the LPC47S457-NS be used in new designs today, given its age?
Yes, the LPC47S457-NS remains viable for new designs targeting long-lifecycle industrial, medical, or military applications where legacy I/O compatibility, BIOS integration (Phoenix 42i), and proven field reliability are prioritized over modern features like USB or PCIe. Aetrix Electronics maintains active inventory and offers traceable, RoHS-compliant units with full documentation. Designers should verify BIOS compatibility and confirm absence of known anomalies via SMSC's archived anomaly reports before finalizing schematics.
What is the role of the X-Bus interface in the LPC47S457-NS?
The X-Bus interface in the LPC47S457-NS provides a dedicated expansion bus supporting up to four external I/O components - most commonly LCD panel controllers - using configurable address mapping and mode selection. It enables direct driving of character/graphic LCDs without consuming host CPU resources or requiring additional bridge logic. The X-Bus also supports Port 80h monitoring for debug visibility and is integral to the device's ability to offload display subsystem control in space-constrained embedded systems.
LPC47S457-NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 128-BFQFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Applications:
- Controller
- Interface:
- LPC
- Voltage - Supply:
- 3.3V
- Supplier Device Package:
- 128-QFP (14x20)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
LPC47S457-NS FAQ
1.How can I place an order for LPC47S457-NS through Aetrix?
Please submit a Request for Quotation (RFQ) for LPC47S457-NS 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 LPC47S457-NS reliable?
The price and inventory of LPC47S457-NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LPC47S457-NS is usually 5 days.
3.What payment methods are accepted for LPC47S457-NS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LPC47S457-NS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LPC47S457-NS?
LPC47S457-NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LPC47S457-NS 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 LPC47S457-NS?
For technical support, including LPC47S457-NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LPC47S457-NS requirements.
6.How does Aetrix verify that LPC47S457-NS is sourced from the original manufacturer or authorized distributors?
All LPC47S457-NS 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 LPC47S457-NS meets industry standards.
7.What is the process for return or replacement of LPC47S457-NS?
All LPC47S457-NS units undergo pre-shipment inspection (PSI). If there is an issue with LPC47S457-NS, 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 LPC47S457-NS part is unused and in its original packaging.
Return procedure for LPC47S457-NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LPC47S457-NS Tags
-
NVT4857UKAZ
NXP Semiconductors
-
TCA8418RTWR
Texas Instruments
-
PCA9546APWR
Texas Instruments
-
MD0100N8-G
Microchip Technology
-
PCA9548APW,118
NXP Semiconductors
-
PCA9540BDP,118
NXP Semiconductors
-
PCA9548APWR
Texas Instruments
-
PCA9546APW,118
NXP Semiconductors
-
PTN3360DBS,518
NXP Semiconductors
-
PCA9546ABS,118
NXP Semiconductors
-
PCA9518PWR
Texas Instruments
-
PCA9545APW,118
NXP Semiconductors
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
