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Microchip Technology AT49LH004-33JX
- Part No.:
- AT49LH004-33JX
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT49LH004-33JX.pdf
- Description:
- IC FLASH 4MBIT PAR 33MHZ 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,583
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Product details
Overview
AT49LH004-33JX from Microchip Technology is a 4-Mbit Firmware Hub (FWH) and Low-Pin Count (LPC) Flash memory IC designed for BIOS storage in Intel 8xx/E7xxx/E8xxx and non-Intel chipset platforms. It supports dual-interface operation (FWH/LPC and A/A Mux), features 32-Kbyte top boot sector + flexible 8/16/64-Kbyte sectoring, operates at 3.0–3.6 V, and uses a 33 MHz PCI clock for FWH/LPC timing.
For engineers reviewing the AT49LH004-33JX datasheet, AT49LH004-33JX pinout, AT49LH004-33JX application, or AT49LH004-33JX equivalent, this page delivers verified interface behavior, hardware write protection logic (TBL/WP), sector lock register support, dual-mode pin mapping, and confirmed PLCC-32/TSOP-40 package compatibility - all critical for BIOS firmware integration and manufacturing programming validation.
Technical Context
The AT49LH004-33JX implements an Intel LPC Interface Specification Rev. 1.1–compliant FWH/LPC interface with 5-signal communication (FWH4/LFRAME, FWH/LAD[3:0]), auto-detects FWH vs. LPC memory cycles via START field decoding (1101b/1110b/0000b), and uses IC pin-controlled mode selection between in-system FWH/LPC and manufacturing A/A Mux interfaces.
Its internal Command User Interface (CUI) orchestrates command execution across both interfaces; fixed program/erase timing eliminates cycle-count calibration; and dual hardware write protect pins (TBL for top boot sector, WP for remaining sectors) operate independently of sector locking registers - enabling layered, deterministic BIOS protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512 Kbytes) - sufficient for full legacy PC/Notebook BIOS code with room for updates and recovery modules. |
| Interface Modes | FWH/LPC (in-system) and Address/Data Multiplexed (A/A Mux, manufacturing) - selected by IC pin level at power-up. |
| Supply Voltage | 3.0 V to 3.6 V - single-supply operation compatible with 3.3 V system rails; no VPP required for programming/erase. |
| Boot Sector Size | 32 Kbytes top boot sector - optimized for critical reset vector and early-boot code; protected independently by TBL pin. |
| Timing Reference | 33 MHz PCI bus clock - synchronous FWH/LPC operation aligned with standard chipset timing budgets. |
| Sector Erase Options | 11-sector (32K+2×8K+16K+7×64K) or 8×64K uniform - enables efficient BIOS modular updates without over-erasing. |
| Hardware Write Protect | TBL (top boot) and WP (all other sectors) - active-low pins providing immediate, latch-free sector lockdown during power-on or runtime. |
Pinout & Package
AT49LH004-33JX is available in 32-lead PLCC and 40-lead TSOP packages. Pin functions are dual-mapped: FWH/LPC interface used in-system; A/A Mux interface used for factory programming. IC pin selects active interface at power-up.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IC | Interface Configuration Control | Low = FWH/LPC mode (default, internal pull-down); high = A/A Mux mode; must be set before reset exit. |
| FWH4/LFRAME | LPC Frame / A/A Mux WE | Indicates start/abort of FWH/LPC cycles; serves as write enable in A/A Mux mode. |
| FWH/LAD[3:0] | FWH/LPC Address/Data Bus / A/A Mux I/O[3:0] | Time-multiplexed address/control/data in FWH/LPC; lower 4-bit data bus in A/A Mux. |
| TBL | Top Boot Sector Lock | Active-low hardware lock for 32-Kbyte boot sector (LPC) or top 64-Kbyte region (FWH); overrides sector registers. |
| WP | Write Protect for Non-Boot Sectors | Active-low lock for all sectors except top boot; independent of TBL and sector locking registers. |
| ID[3:0] | Device Identification Inputs | Strap-selectable 4-bit ID for multi-device FWH bus; boot device must be 0000; internally pulled down. |
| GPI[4:0] | General-Purpose Inputs | Five user-configurable inputs readable via GPI register; mapped to A[10:6] in A/A Mux mode. |
Key Features
| Feature | Design Value |
|---|---|
| Auto-Detect FWH/LPC Cycles | Decodes START field (1101b/1110b/0000b) to route commands correctly - eliminates external mode logic. |
| Flexible Sector Architecture | Two erase command options yield either 11 mixed-size sectors or 8 uniform 64-Kbyte sectors - maximizes BIOS code density. |
| Dual Hardware Write Protection | TBL + WP pins provide immediate, non-volatile sector lockdown - critical for secure BIOS boot integrity. |
| Fixed Program/Erase Timing | Timing independent of cumulative P/E cycles - removes need for system-level wear-life calibration or margining. |
| PCI-Compliant Buffers | FWH/LPC interface meets PCI electrical specs - ensures reliable signal integrity on 33 MHz bus without external termination. |
Applications
| Desktop PC BIOS Storage | Notebook BIOS Storage |
|---|---|
|
Use Scenario: Storing and executing core BIOS firmware on Intel 8xx-series chipsets with FWH interface. IC Role / Device Role / Timing Role: Firmware Hub (FWH) flash memory providing boot code, POST routines, and hardware initialization sequences. Use Value: Top 32-Kbyte boot sector with dedicated TBL pin ensures reset vector and early-boot code remain immutable during field updates. |
Use Scenario: Hosting compressed BIOS image and recovery partition in space-constrained notebook motherboards. IC Role / Device Role / Timing Role: LPC Flash memory interfacing with non-Intel south bridge for BIOS read/write operations. Use Value: Dual-interface support allows in-system FWH/LPC access and out-of-system A/A Mux programming - streamlining OEM manufacturing and repair workflows. |
| Embedded Industrial Controller BIOS | Legacy Server Platform Firmware |
|
Use Scenario: Providing robust, field-upgradable firmware for fanless industrial PCs operating in extended temperature ranges. IC Role / Device Role / Timing Role: Secure BIOS storage with hardware write protection (TBL/WP) and sector locking registers. Use Value: Independent TBL and WP pins enable hierarchical protection - boot sector locked permanently while application sectors remain updateable. |
Use Scenario: Supporting BIOS redundancy and fail-safe recovery in dual-socket server platforms with E7xxx/E8xxx chipsets. IC Role / Device Role / Timing Role: Primary FWH flash for main BIOS image and secondary device for backup/recovery image. Use Value: ID[3:0] strapping allows up to 16 devices on same FWH bus - enabling mirrored or hot-swappable firmware configurations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar firmware hub and LPC flash applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Winbond W29GL032C | 32-Mbit density, 1.8 V core / 3.3 V I/O, supports only LPC (no FWH mode), no TBL pin. | Targeted at newer low-power platforms; lacks Intel FWH compatibility and top-boot hardware lock. | Select when migrating to higher-density, lower-voltage designs where FWH compliance is not required. |
| Spansion S29GL032N | 32-Mbit, 3.0–3.6 V, supports FWH/LPC but uses different START field encoding and lacks GPI pins. | Requires modified host driver for FWH cycle initiation; no general-purpose inputs for board-level configuration. | Choose for cost-sensitive volume production where GPI flexibility and exact AT49LH004-33JX timing are non-critical. |
Compared with W29GL032C and S29GL032N, the AT49LH004-33JX uniquely combines Intel FWH compliance, dual hardware write protect (TBL/WP), five GPIs for system customization, and flexible 11-sector erase - making it irreplaceable for legacy BIOS designs requiring strict Intel 8xx/E7xxx chipset interoperability and boot-sector security.
Availability
AT49LH004-33JX is available at Aetrix Electronics and suitable for desktop PC BIOS storage, notebook firmware deployment, and embedded industrial controller boot applications requiring stable component supply and long-term lifecycle support.
Supply support for AT49LH004-33JX 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 memory solutions, with strong heritage in embedded control and firmware infrastructure.
The AT49LH004-33JX belongs to Microchip's legacy Firmware Hub and LPC Flash memory product line, engineered specifically for BIOS firmware storage in Intel and compatible PC/platform controller hub architectures.
FAQ
What interface modes does the AT49LH004-33JX support, and how is mode selection controlled?
The AT49LH004-33JX supports two distinct interface modes: FWH/LPC for in-system operation and Address/Data Multiplexed (A/A Mux) for manufacturing programming. Mode selection is controlled exclusively by the IC pin: low (internally pulled down) enables FWH/LPC mode; high enables A/A Mux mode. The IC pin state must be established at power-up or before exiting reset and cannot be changed dynamically during operation. This hardwired selection ensures deterministic interface behavior without software overhead.
How does the AT49LH004-33JX handle hardware write protection for the boot sector versus other memory regions?
The AT49LH004-33JX implements two independent hardware write protect pins: TBL (Top Boot Lock) and WP (Write Protect). TBL is active-low and protects only the top 32-Kbyte boot sector in LPC mode (or top 64-Kbyte region in FWH mode), overriding sector locking registers. WP is also active-low and protects all remaining sectors except the top boot region. Both pins function regardless of interface mode and provide immediate, non-volatile protection - essential for preventing accidental corruption of critical boot code.
What sector erase configurations are available on the AT49LH004-33JX, and how are they selected?
The AT49LH004-33JX offers two sector erase configurations selectable via distinct erase commands: (1) 11-sector layout comprising one 32-Kbyte top boot sector, two 8-Kbyte sectors, one 16-Kbyte sector, and seven 64-Kbyte sectors; or (2) eight uniform 64-Kbyte sectors. This flexibility allows optimal alignment with BIOS module boundaries - minimizing wasted space when updating discrete firmware components while maintaining compatibility with legacy erase algorithms.
Can the AT49LH004-33JX be used with non-Intel chipsets, and what interface mode is required?
Yes, the AT49LH004-33JX can be used with non-Intel chipsets as an LPC Flash memory device. In this configuration, it operates in LPC mode using the FWH/LPC interface (IC pin low), responding to START field 0000b and supporting LPC memory read/write cycles. Its auto-detection capability identifies the cycle type, enabling seamless integration with PCI south bridges or other LPC-compatible controllers - provided the host implements the Intel LPC Interface Specification Rev. 1.1 timing and protocol.
What is the role of the GPI[4:0] pins on the AT49LH004-33JX, and how are they accessed?
The GPI[4:0] pins on the AT49LH004-33JX are five general-purpose inputs that provide board-level configuration flexibility. Their logic states can be read by the host system via the GPI register using the FWH/LPC interface. To ensure valid sampling, GPI pin levels must be stable before the PCI clock cycle in which the read is initiated and held until the cycle completes. In A/A Mux mode, these same pins serve as address lines A[10:6], demonstrating their dual-role design for both runtime configurability and manufacturing programming efficiency.
AT49LH004-33JX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- FLASH
- Technology:
- FLASH
- Memory Size:
- 4Mbit
- Memory Organization:
- 512K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- 33 MHz
- Write Cycle Time - Word, Page:
- 50µs
- Access Time:
- -
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- 0°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT49LH004-33JX FAQ
1.How can I place an order for AT49LH004-33JX through Aetrix?
Please submit a Request for Quotation (RFQ) for AT49LH004-33JX 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 AT49LH004-33JX reliable?
The price and inventory of AT49LH004-33JX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT49LH004-33JX is usually 5 days.
3.What payment methods are accepted for AT49LH004-33JX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT49LH004-33JX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT49LH004-33JX?
AT49LH004-33JX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT49LH004-33JX 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 AT49LH004-33JX?
For technical support, including AT49LH004-33JX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT49LH004-33JX requirements.
6.How does Aetrix verify that AT49LH004-33JX is sourced from the original manufacturer or authorized distributors?
All AT49LH004-33JX 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 AT49LH004-33JX meets industry standards.
7.What is the process for return or replacement of AT49LH004-33JX?
All AT49LH004-33JX units undergo pre-shipment inspection (PSI). If there is an issue with AT49LH004-33JX, 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 AT49LH004-33JX part is unused and in its original packaging.
Return procedure for AT49LH004-33JX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT49LH004-33JX Tags
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