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Microchip Technology AT49LH004-33JX-T
- Part No.:
- AT49LH004-33JX-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT49LH004-33JX-T.pdf
- Description:
- IC FLASH 4MBIT PAR 33MHZ 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,001
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Product details
Overview
AT49LH004-33JX-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 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-T datasheet, AT49LH004-33JX-T pinout, AT49LH004-33JX-T application, or AT49LH004-33JX-T equivalent, key selection considerations include LPC/FWH interface auto-detection, hardware write protection via TBL/WP pins, sector locking registers, 32-lead PLCC package compatibility, and single-voltage 3.3 V system integration for legacy PC and notebook BIOS designs.
Technical Context
The AT49LH004-33JX-T implements a dual-mode interface architecture controlled by the IC pin: low enables FWH/LPC mode (5-signal, 33 MHz PCI-synchronous, byte-wide LAD[3:0] bus); high enables A/A Mux mode (11-pin multiplexed address + 8-bit data). It uses fixed program/erase timing independent of cycle count, eliminating system calibration needs.
Its memory array supports two erase configurations: 11-sector layout (32-KB top boot + two 8-KB + one 16-KB + seven 64-KB sectors) or eight uniform 64-KB sectors. Sector protection combines hardware (TBL for top boot, WP for remaining sectors) and register-based locking, with ID[3:0] strapping enabling multi-device bus addressing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512 K × 8) - provides full BIOS code storage for legacy x86 platforms without external expansion. |
| Interface Standard | Intel LPC Interface Spec 1.1 - ensures interoperability with ICH-based south bridges and non-Intel LPC controllers. |
| Supply Voltage | 3.0 V to 3.6 V - enables direct connection to 3.3 V system rails; no VPP or auxiliary voltage required for programming/erasing. |
| Operating Clock | 33 MHz PCI clock - synchronizes FWH/LPC transactions to standard desktop/notebook platform timing. |
| Sector Architecture | Configurable: 11-sector (32-KB top boot + variable sub-sectors) or 8 × 64-KB uniform - optimizes BIOS module placement and minimizes wasted space. |
| Hardware Protection | TBL (top boot lock) + WP (write protect) pins - enable board-level, non-volatile sector lockdown independent of register state. |
| Package Type | 32-lead PLCC - surface-mount compatible with legacy BIOS socket footprints and rework-friendly for manufacturing. |
Pinout & Package
AT49LH004-33JX-T is supplied in a 32-lead Plastic Leaded Chip Carrier (PLCC) package with J-lead profile, suitable for through-hole or surface-mount assembly. Pin functions are dual-mode: FWH/LPC interface active when IC = low; A/A Mux interface active when IC = high.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IC | Interface Configuration Control | Input that selects FWH/LPC (low) or A/A Mux (high); internally pulled down - optional pull-up only if A/A Mux mode required. |
| FWH4/LFRAME | LPC Frame / Write Enable | In FWH/LPC mode: initiates/aborts cycles; in A/A Mux mode: acts as WE - critical for bus arbitration and command synchronization. |
| FWH/LAD[3:0] | Address/Data Multiplex Bus | 4-bit bidirectional bus carrying START, IDSEL, MADDR, MSIZE, and data nibbles - requires precise 33 MHz timing alignment. |
| TBL & WP | Hardware Write Protect Inputs | TBL locks top 32-KB boot sector; WP locks all other sectors - both override software locking and survive power loss. |
| ID[3:0] | Device Identification Inputs | Strap pins assigning unique FWH device ID (e.g., 0000 for boot device); internally pulled down - simplifies single-device systems. |
| GPI[4:0] | General-Purpose Inputs | Five configurable inputs readable via GPI register - provide board-level status signals (e.g., jumper settings, revision ID) without extra GPIOs. |
Key Features
| Feature | Design Value |
|---|---|
| Auto-detect FWH vs. LPC cycles | Eliminates firmware configuration overhead: device interprets START field (1101b/1110b = FWH; 0000b = LPC) to route commands correctly. |
| Dual-interface support | Enables in-system FWH/LPC operation while reserving A/A Mux for factory programming - avoids dedicated programmers in production. |
| Flexible sector erase options | Two distinct erase commands yield either 11-sector (BIOS-optimized) or 8×64-KB (uniform) layouts - maximizes memory utilization per platform requirement. |
| Fixed program/erase timing | Guarantees consistent latency across lifetime - removes need for wear-leveling or cycle-count compensation in host BIOS. |
| Green (Pb/Halide-free) packaging | Meets RoHS Directive 2011/65/EU - supports environmental compliance for OEM shipments without derating or qualification impact. |
Applications
| Intel Chipset-Based Desktop Motherboards | Non-Intel LPC Platform Notebooks |
|---|---|
Use Scenario: Storing and executing core BIOS firmware on motherboards using Intel 8xx/E7xxx/E8xxx chipsets with ICH south bridge. IC Role / Device Role / Timing Role: Firmware Hub (FWH) providing secure, low-latency boot code access via LPC bus synchronized to 33 MHz PCI clock. Use Value: Enables hardware-level top-boot protection (TBL pin) and register-based sector locking to prevent accidental BIOS corruption during updates. | Use Scenario: Hosting BIOS image on laptops with AMD or VIA LPC-compatible chipsets lacking native FWH support. IC Role / Device Role / Timing Role: LPC Flash memory responding to standard LPC memory read/write cycles initiated by south bridge controller. Use Value: Delivers identical 4-Mbit density and sectoring flexibility as FWH mode, but with broader chipset compatibility via START=0000b detection. |
| Legacy Industrial PC BIOS Modules | Embedded Systems with Field-Programmable BIOS |
Use Scenario: Providing upgradeable firmware storage in fanless IPCs where long-term component availability and thermal stability are critical. IC Role / Device Role / Timing Role: Nonvolatile BIOS memory operating at 3.3 V with fixed-timing erase/program - immune to voltage drift or aging effects. Use Value: PLCC package allows socketed replacement; green packaging meets industrial environmental standards without performance trade-offs. | Use Scenario: Enabling in-field BIOS updates via A/A Mux interface using standard ISP programmers during maintenance or security patch deployment. IC Role / Device Role / Timing Role: Dual-mode Flash supporting FWH/LPC for runtime and A/A Mux (11-pin addr + 8-bit data) for out-of-band programming. Use Value: Eliminates need for separate programming fixtures - same device serves both production programming and field service reflash. |
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 |
|---|---|---|---|
| EN29LV040A-70TCP | Single 512-KB uniform sector; no FWH protocol support; 70 ns access time; 3.0–3.6 V supply. | Requires external logic for LPC interface emulation; lacks TBL/WP hardware protection and ID strapping. | Use only if FWH auto-detection and multi-device bus addressing are unnecessary and uniform erase suffices. |
| MX29LV040CTC-70G | 4-Mbit, 3.3 V, 70 ns access; supports Common Flash Interface (CFI); no FWH/LPC mode or IC pin. | Relies on standard parallel interface - incompatible with LPC bus timing and START field decoding. | Select when migrating to CFI-compliant BIOS tools and abandoning legacy LPC/FWH infrastructure. |
Compared with EN29LV040A-70TCP and MX29LV040CTC-70G, the AT49LH004-33JX-T uniquely delivers native Intel FWH/LPC compliance, hardware sector protection, and dual-interface flexibility - making it irreplaceable in designs requiring boot-time security, chipset interoperability, and field-programmable BIOS without interface translation.
Availability
AT49LH004-33JX-T is available at Aetrix Electronics and suitable for Intel chipset motherboard design, legacy notebook BIOS replacement, and industrial PC firmware storage requiring stable component supply across extended product lifecycles.
Supply support for AT49LH004-33JX-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 a focus on reliability, longevity, and industrial-grade qualification.
The AT49LH004-33JX-T belongs to Microchip's legacy Firmware Hub and LPC Flash memory product line, engineered specifically for BIOS code storage in x86 platforms where Intel LPC specification compliance, hardware write protection, and long-term obsolescence management are critical.
FAQ
What interface modes does the AT49LH004-33JX-T support, and how are they selected?
The AT49LH004-33JX-T supports two interface modes: FWH/LPC (for in-system operation) and A/A Mux (for manufacturing programming). Mode selection is controlled by the IC pin: low enables FWH/LPC; high enables A/A Mux. The IC pin is internally pulled down, so no external connection is needed unless A/A Mux mode is required. This dual-mode capability allows the same AT49LH004-33JX-T device to serve both runtime and production programming roles without redesign.
Does the AT49LH004-33JX-T require a separate programming voltage (VPP)?
No, the AT49LH004-33JX-T operates entirely from a single 3.0–3.6 V supply for read, program, and erase operations - no VPP or auxiliary voltage is needed. This simplifies power design and eliminates risk of overvoltage damage during in-system updates. All internal charge pumps are self-contained, and timing is fixed regardless of cumulative program/erase cycles, ensuring predictable behavior throughout the AT49LH004-33JX-T's operational life.
How does hardware write protection work on the AT49LH004-33JX-T?
The AT49LH004-33JX-T implements two dedicated hardware write protect pins: TBL (Top Boot Lock) and WP (Write Protect). When TBL is low, the top 32-KB boot sector is locked against program/erase regardless of sector locking register state. When WP is low, all other sectors are protected. Both pins override software-based locking and remain active across power cycles. This dual-layer protection ensures BIOS integrity even if firmware-level controls are compromised - a critical feature for the AT49LH004-33JX-T in secure boot environments.
Can the AT49LH004-33JX-T be used with non-Intel chipsets?
Yes, the AT49LH004-33JX-T supports LPC Flash operation with non-Intel chipsets via automatic cycle detection: when the START field is 0000b, the device enters LPC memory mode and responds to standard LPC memory read/write cycles. This allows use with AMD, VIA, and other LPC-compliant south bridges without modification. The AT49LH004-33JX-T maintains full 4-Mbit density and sectoring flexibility in this mode, making it a drop-in solution for diverse platform architectures.
What is the purpose of the ID[3:0] pins on the AT49LH004-33JX-T?
The ID[3:0] pins on the AT49LH004-33JX-T provide hardware-based device identification for multi-flash systems. They are strapped to assign a unique 4-bit ID (e.g., 0000 for boot device), enabling the host to select individual devices on a shared FWH/LPC bus. These pins are internally pulled down, so no external resistors are needed in single-device configurations. Reading the ID[3:0] state via the GPI register allows runtime verification of device identity - an essential function for BIOS validation and redundancy management in the AT49LH004-33JX-T.
AT49LH004-33JX-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)
AT49LH004-33JX-T FAQ
1.How can I place an order for AT49LH004-33JX-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT49LH004-33JX-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 AT49LH004-33JX-T reliable?
The price and inventory of AT49LH004-33JX-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT49LH004-33JX-T is usually 5 days.
3.What payment methods are accepted for AT49LH004-33JX-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT49LH004-33JX-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT49LH004-33JX-T?
AT49LH004-33JX-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT49LH004-33JX-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 AT49LH004-33JX-T?
For technical support, including AT49LH004-33JX-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT49LH004-33JX-T requirements.
6.How does Aetrix verify that AT49LH004-33JX-T is sourced from the original manufacturer or authorized distributors?
All AT49LH004-33JX-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 AT49LH004-33JX-T meets industry standards.
7.What is the process for return or replacement of AT49LH004-33JX-T?
All AT49LH004-33JX-T units undergo pre-shipment inspection (PSI). If there is an issue with AT49LH004-33JX-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 AT49LH004-33JX-T part is unused and in its original packaging.
Return procedure for AT49LH004-33JX-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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