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Microchip Technology AT49LH004-33JC-T
- Part No.:
- AT49LH004-33JC-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT49LH004-33JC-T.pdf
- Description:
- IC FLASH 4MBIT PAR 33MHZ 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,714
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Product details
Overview
AT49LH004-33JC-T 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 hardware write protection via TBL and WP pins, delivers 33 MHz PCI clock-synchronized timing, and operates across 3.0V–3.6V supply voltage.
For engineers reviewing the AT49LH004-33JC-T datasheet, AT49LH004-33JC-T pinout, AT49LH004-33JC-T application, or AT49LH004-33JC-T equivalent, this page provides verified interface configuration logic, sector locking register behavior, top-boot sector protection scope, FWH/LPC cycle decoding rules, and dual-package (PLCC/TSOP) mechanical compatibility details essential for BIOS firmware integration and manufacturing programming validation.
Technical Context
The AT49LH004-33JC-T implements an Intel LPC Interface Specification Rev. 1.1–compliant dual-mode controller with automatic FWH/LPC cycle detection based on START field values (1101b/1110b for FWH, 0000b for LPC). Its internal Command User Interface (CUI) routes commands between the FWH/LPC and A/A Mux interfaces under IC pin control.
It uses fixed-timing program/erase operations independent of cumulative cycling history, eliminating system calibration needs. Sector protection combines hardware (TBL for top 32-Kbyte boot sector, WP for remaining sectors) and register-based locking, with ID[3:0] strapping enabling multi-device bus selection in FWH mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512 Kbytes) flash array, sufficient for full BIOS code plus update space in legacy PC platforms. |
| Interface Modes | FWH/LPC (33 MHz PCI clock, 5-signal bus) and A/A Mux (11-pin address + 8-pin data), selected by IC pin state at power-up. |
| Sector Architecture | Flexible erase: either 11-sector layout (32-KB top boot + two 8-KB + one 16-KB + seven 64-KB) or eight uniform 64-KB sectors. |
| Write Protection | Dual hardware lock: TBL pin disables top boot sector writes/erases; WP pin disables all other sector writes/erases-both override software locks. |
| Supply Voltage | 3.0V to 3.6V single supply for read, program, and erase-no VPP required, simplifying power design. |
| Package Options | 32-lead PLCC and 40-lead TSOP; AT49LH004-33JC-T specifically uses 32-lead PLCC with JEDEC-standard footprint. |
| Timing Consistency | Fixed program/erase times regardless of wear level-enables deterministic BIOS update timing without runtime calibration. |
Pinout & Package
AT49LH004-33JC-T is packaged in a 32-lead Plastic Leaded Chip Carrier (PLCC) with standard JEDEC MO-047A outline, 1.78 mm body height, and 0.050-inch lead pitch. Pin 1 is located at the index corner adjacent to the notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IC | Interface Configuration Select | Low = FWH/LPC mode active; high = A/A Mux mode active; internal pull-down ensures default FWH operation if unconnected. |
| TBL | Top Boot Sector Lock | Low = hardware lock of top 32-KB boot sector (LPC mode) or top 64-KB region (FWH mode); overrides sector locking registers. |
| WP | Write Protect | High = disable hardware protection on all non-top-boot sectors; sector locking registers remain functional regardless of WP state. |
| ID[3:0] | Device Identification Inputs | Strapped binary ID (e.g., 0000 for boot device); used during FWH IDSEL field matching to select target device on shared bus. |
| GPI[4:0] | General-Purpose Inputs | Five user-configurable inputs readable via GPI register; mapped to A[10:6] in A/A Mux mode for extended addressing. |
| FWH4/LFRAME | LPC Frame Control | Active-low initiation signal for FWH/LPC cycles; also serves as WE in A/A Mux mode. |
| FWH/LAD[3:0] | LPC Address/Data Bus | Time-multiplexed 4-bit bus carrying START, IDSEL, MADDR, MSIZE, SYNC, and data nibbles; PCI-compliant timing. |
| RST / INIT | Reset Inputs | RST resets internal automation and forces high-Z on FWH/LAD[3:0]; INIT mirrors RST but connects to chipset INIT signal. |
| RDY/BSY / RES | Status Output / Reserved | RDY/BSY reflects Status Register bit 7 (busy flag); RES pins are reserved-may float or drive per VIH/VIL specs. |
Key Features
| Feature | Design Value |
|---|---|
| Auto-detect FWH vs. LPC cycles | Eliminates external mode-select logic-START field (1101b/1110b vs. 0000b) automatically configures interface behavior without firmware intervention. |
| Two-sector erase configurations | Enables optimal BIOS partitioning: 11-sector layout preserves legacy boot module isolation; uniform 64-KB layout simplifies manufacturing programming. |
| Hardware + register sector locking | Provides layered security: TBL/WP pins enforce board-level protection; sector locking registers allow dynamic, software-controlled fine-grained access control. |
| PCI clock-synchronized interface | Uses existing 33 MHz PCI clock-no additional clock source needed, reducing BOM count and timing skew risk in motherboard designs. |
| Single-supply 3.0–3.6V operation | Removes need for charge pumps or high-voltage generators-simplifies power delivery and improves reliability in 3V-only systems. |
Applications
| Intel Chipset BIOS Storage | Non-Intel Platform LPC Flash |
|---|---|
Use Scenario: Storing and updating core BIOS firmware on motherboards using Intel 8xx, E7xxx, or E8xxx ICH chipsets. IC Role / Device Role / Timing Role: Firmware Hub (FWH) acting as primary boot memory, responding to FWH memory read/write cycles initiated by the ICH over LPC bus. Use Value: Hardware TBL pin ensures critical boot code remains protected during field updates; auto-detection of FWH cycles eliminates interface configuration errors in complex multi-device LPC topologies. | Use Scenario: Providing BIOS storage on AMD or VIA-based notebooks where LPC interface is used without FWH protocol support. IC Role / Device Role / Timing Role: LPC Flash memory responding to standard LPC memory cycles (START=0000b, CYCTYPE+DIR field), not FWH-specific commands. Use Value: Dual-mode capability allows same part number to serve both Intel and non-Intel platforms-reducing inventory SKUs while maintaining full LPC compliance and timing. |
| Manufacturing In-System Programming | BIOS Recovery Module |
Use Scenario: High-speed parallel programming of BIOS images during PC assembly using A/A Mux interface. IC Role / Device Role / Timing Role: Address/data multiplexed Flash device accepting 11-bit address + 8-bit data via dedicated A/A Mux pins (A[10:0], I/O[7:0], R/C, OE, WE). Use Value: Dedicated A/A Mux interface enables faster, more reliable programming than LPC-based methods-critical for production line throughput and yield. | Use Scenario: Enabling fail-safe BIOS recovery after corrupted update, using top-boot sector to host recovery loader. IC Role / Device Role / Timing Role: Top-boot Flash memory with hardware-locked 32-KB sector (via TBL pin) that remains writable only through secure recovery path. Use Value: Physical TBL pin lock prevents accidental overwrite of recovery code-even if firmware bugs or malware attempt to erase boot sector. |
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 W39L040PZ | 4-Mbit LPC Flash with identical 32-lead PLCC package and 3.3V operation, but lacks FWH mode support and TBL pin-only LPC-compatible. | Restricted to non-Intel LPC platforms; cannot replace AT49LH004-33JC-T in Intel chipset designs requiring FWH protocol. | Select when FWH functionality is unnecessary and cost optimization is prioritized over dual-protocol flexibility. |
| Spansion S29GL032N90TFI040 | 32-Mbit parallel NOR Flash in 48-TSOP, supporting CFI command set-not LPC/FWH compliant; requires different controller interface. | Used in embedded systems with dedicated NOR controllers-not drop-in for LPC bus BIOS slots. | Choose only for new designs migrating away from LPC architecture toward scalable parallel NOR with higher density. |
Compared with W39L040PZ and S29GL032N90TFI040, the AT49LH004-33JC-T uniquely supports both Intel FWH and generic LPC modes in one device, retains hardware top-boot protection via TBL, and fits legacy 32-lead PLCC sockets-making it irreplaceable for maintaining compatibility in existing Intel-platform BIOS designs.
Availability
AT49LH004-33JC-T is available at Aetrix Electronics and suitable for Intel chipset BIOS storage, non-Intel LPC platform firmware, and manufacturing in-system programming requiring stable component supply and long-lifecycle support.
Supply support for AT49LH004-33JC-T 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with broad industrial and computing market presence.
The AT49LH004-33JC-T belongs to Microchip's legacy Firmware Hub and LPC Flash product line, engineered specifically to meet Intel's BIOS firmware interface requirements while enabling interoperability across heterogeneous chipset ecosystems.
FAQ
What interface modes does the AT49LH004-33JC-T support, and how is mode selection controlled?
The AT49LH004-33JC-T supports two interface modes: FWH/LPC for in-system operation and A/A Mux for manufacturing programming. Mode selection is controlled exclusively by the IC pin-low enables FWH/LPC mode, high enables A/A Mux mode. The IC pin has an internal pull-down resistor (20–100 kΩ), so leaving it unconnected defaults the AT49LH004-33JC-T to FWH/LPC operation at power-up. This configuration must be set before reset release and cannot be changed dynamically during operation.
How does hardware write protection work on the AT49LH004-33JC-T, and what is the relationship between TBL, WP, and sector locking registers?
The AT49LH004-33JC-T implements three-tiered write protection: TBL pin locks the top 32-KB boot sector (LPC mode) or top 64-KB region (FWH mode); WP pin locks all other sectors; sector locking registers provide software-controllable per-sector read/write enable/disable. Critically, TBL and WP are hardware overrides-their low states disable writes/erases regardless of register settings. Sector locking registers remain fully functional even when TBL or WP is asserted, allowing layered security policies in BIOS firmware.
Can the AT49LH004-33JC-T be used on non-Intel chipsets, and what interface protocol does it use in that case?
Yes, the AT49LH004-33JC-T can be used on non-Intel chipsets such as AMD or VIA south bridges. In those systems, it operates strictly as an LPC Flash memory device using standard LPC memory cycles (START field = 0000b, followed by CYCTYPE+DIR and 32-bit MADDR). It does not require FWH-specific handshake signals or protocols, making the AT49LH004-33JC-T compatible with any LPC bus master that adheres to Intel's LPC Interface Specification Rev. 1.1.
What are the two sector erase configurations supported by the AT49LH004-33JC-T, and how are they selected?
The AT49LH004-33JC-T supports two distinct sector erase layouts: (1) an optimized 11-sector configuration (32-KB top boot + two 8-KB + one 16-KB + seven 64-KB sectors) and (2) eight uniform 64-KB sectors. Selection is determined solely by the erase command issued-no hardware or register setting changes are required. The 11-sector layout maximizes BIOS code efficiency by isolating critical modules; the uniform layout simplifies high-volume programming in manufacturing environments.
Is the AT49LH004-33JC-T still recommended for new designs, and what is its status in Microchip's product lifecycle?
No, the AT49LH004-33JC-T is marked "Not Recommended for New Design" per its official datasheet (3383D–FLASH–6/05). It remains available for legacy system repair, BIOS rework, and continuity programs but is not intended for inclusion in newly developed platforms. Microchip continues to support the AT49LH004-33JC-T with full datasheet documentation and obsolescence notifications per JESD46 standards, ensuring predictable supply for existing production ramps.
AT49LH004-33JC-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tape & Reel (TR)
- 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)
AT49LH004-33JC-T FAQ
1.How can I place an order for AT49LH004-33JC-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT49LH004-33JC-T 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 AT49LH004-33JC-T reliable?
The price and inventory of AT49LH004-33JC-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT49LH004-33JC-T is usually 5 days.
3.What payment methods are accepted for AT49LH004-33JC-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT49LH004-33JC-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT49LH004-33JC-T?
AT49LH004-33JC-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT49LH004-33JC-T 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 AT49LH004-33JC-T?
For technical support, including AT49LH004-33JC-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT49LH004-33JC-T requirements.
6.How does Aetrix verify that AT49LH004-33JC-T is sourced from the original manufacturer or authorized distributors?
All AT49LH004-33JC-T 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 AT49LH004-33JC-T meets industry standards.
7.What is the process for return or replacement of AT49LH004-33JC-T?
All AT49LH004-33JC-T units undergo pre-shipment inspection (PSI). If there is an issue with AT49LH004-33JC-T, 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 AT49LH004-33JC-T part is unused and in its original packaging.
Return procedure for AT49LH004-33JC-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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