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Microchip Technology AT29C040A-90TU
- Part No.:
- AT29C040A-90TU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-TFSOP (0.724", 18.40mm Width)
- Datasheet:
-
AT29C040A-90TU.pdf
- Description:
- IC FLASH 4MBIT PARALLEL 32TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,666
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Product details
Overview
AT29C040A-90TU from Atmel is a 4-Mbit (512K × 8) 5V-only Flash memory IC organized in 2048 sectors of 256 bytes each, featuring 90 ns read access time, sector-based reprogramming, and hardware/software data protection. It operates across –40°C to +85°C and supports in-system programming for embedded boot code storage and firmware updates.
For engineers reviewing the AT29C040A-90TU datasheet, AT29C040A-90TU pinout, AT29C040A-90TU application, or AT29C040A-90TU equivalent, key selection considerations include 90 ns read timing, 256-byte sector architecture, dual 16K boot block lockout, DATA polling/Toggle Bit program status detection, and PLCC-32/TSOP-32 packaging options for legacy industrial control and BIOS storage designs.
Technical Context
The AT29C040A-90TU implements a sector-erase-and-program architecture with internal latching of 256-byte sector data and automatic erase-before-write sequencing controlled by an on-chip timer. Its operation requires no external high-voltage supply - all commands execute using only 5V ±10%.
It supports two independent boot blocks (first and last 16K bytes), each programmable-lockable via a 7-command algorithm; once locked, those blocks resist erasure and prohibit chip-erase. Data integrity is enforced via VCC sense (<3.8V inhibit), noise-filtered WE/CE inputs, and software data protection requiring a 3-byte unlock sequence before any sector write.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512K × 8), sufficient for full BIOS or bootloader images in legacy x86 and microcontroller systems |
| Read Access Time | 90 ns - enables direct execution from flash in timing-critical 5V microcontroller interfaces |
| Sector Size | 256 bytes - allows fine-grained firmware patching without full-device erasure |
| Program Cycle Time | 10 ms per sector - deterministic timing for host controller timeout handling |
| Endurance | >10,000 write/erase cycles per sector - validated for field-upgradable embedded firmware |
| Supply Voltage | 5V ±10% - compatible with legacy 5V logic rails and eliminates need for charge pumps |
| Standby Current | 100 µA CMOS - supports low-power suspend modes in battery-backed systems |
Pinout & Package
AT29C040A-90TU is available in 32-lead TSOP (Type 1, 8 × 20 mm) and 32-lead PLCC packages. The TSOP variant (designated by suffix 'T') is used here per the 'TU' ordering code.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A18 | Address Inputs | 19-bit address bus supporting full 512K-word addressing; A8–A18 select sector, A0–A7 select byte within sector |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface for read data output and program data input; supports DATA polling on I/O7 and Toggle Bit on I/O6 |
| CE | Chip Enable | Active-low global enable; must be low for read, program, or identification mode; inhibits writes when high |
| OE | Output Enable | Active-low output control; places I/O pins in high-Z when high; required high during byte load and program cycles |
| WE | Write Enable | Active-low write strobe; initiates byte load and program sequences; must be pulsed within 150 µs of prior pulse for sector loading |
| VCC | Power Supply | +5V ±10% main supply; internal VCC sense disables programming if voltage drops below ~3.8V |
| GND | Ground | Reference return for all signals and power; decoupling required near VCC pin due to 40 mA active current |
| NC | No Connect | Unbonded pin; must remain floating - no external connection permitted |
Key Features
| Feature | Design Value |
|---|---|
| Single 5V Reprogramming | Eliminates need for 12V programming supplies or external charge pumps - simplifies system power design |
| Hardware Data Protection | VCC sense, 5 ms power-on delay, and 15 ns noise filtering prevent accidental writes during brown-out or EMI events |
| Dual Boot Block Lockout | Independent 16K-byte lockable regions at 0x00000–0x03FFF and 0x7C000–0x7FFFF - secures primary and fallback boot code |
| DATA Polling & Toggle Bit | Real-time program status feedback via I/O7 complement or I/O6 toggling - enables interrupt-driven host firmware without fixed delays |
| Green Pb/Halide-free Packaging | RoHS-compliant TSOP-32 package meets environmental compliance requirements for industrial OEM production |
Applications
| Industrial PLC Firmware Storage | Legacy PC BIOS Memory |
|---|---|
Use Scenario: Storing firmware and configuration data in programmable logic controllers where field updates are infrequent but critical. IC Role / Device Role / Timing Role: Nonvolatile code storage with sector-level reprogrammability and boot block lockout to preserve core runtime logic. Use Value: Prevents corruption of operational firmware during partial updates; 10,000-cycle endurance ensures >10-year field life under typical maintenance intervals. |
Use Scenario: Serving as the primary BIOS ROM in older x86 motherboards requiring in-circuit reflash capability. IC Role / Device Role / Timing Role: 5V-compatible, EPROM-equivalent read interface with 90 ns access for CPU fetch timing compliance. Use Value: Enables BIOS recovery via software tools without removing the chip; boot block lockout protects reset vector and POST routines. |
| Embedded System Bootloader | Telecom Equipment Configuration |
Use Scenario: Hosting bootloader code that initializes DDR, configures peripherals, and loads application firmware from external media. IC Role / Device Role / Timing Role: Secure, lockable first-stage boot memory with deterministic 10 ms sector programming for fail-safe updates. Use Value: Dual boot blocks allow A/B firmware partitioning; software data protection prevents unauthorized modification during power transitions. |
Use Scenario: Storing calibration tables, line-card profiles, and protocol stacks in carrier-grade DSLAMs and base station controllers. IC Role / Device Role / Timing Role: High-reliability, sector-erasable nonvolatile memory supporting remote firmware patches over management interfaces. Use Value: 256-byte granularity enables targeted parameter updates without disrupting active service; 100 µA standby current minimizes board-level leakage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV040B-90EC | 4 Mbit, 90 ns, 3.3V core with 5V I/O tolerance; uses different command set and lacks boot block lockout | Requires level-shifting in pure 5V systems; no hardware-enforced boot region protection | Choose only if migrating to 3.3V domains or needing longer endurance (>100K cycles) |
| MX29LV040CTTI-90G | 4 Mbit, 90 ns, 3.3V supply; software-compatible command set but no VCC-sense hardware protection | Not pin-compatible; requires PCB redesign; lacks 5V-only simplicity and brown-out immunity | Select when lower active power (25 mA vs. 40 mA) and newer process node are prioritized over legacy 5V compatibility |
Compared with AT29C040A-90TU, AM29LV040B-90EC offers higher endurance but sacrifices 5V-native operation and boot block security, while MX29LV040CTTI-90G reduces power and cost at the expense of hardware data protection robustness and pinout compatibility in existing 5V designs.
Availability
AT29C040A-90TU is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS replacement, embedded bootloader implementation, and telecom equipment configuration requiring stable component supply and long-term obsolescence support.
Supply support for AT29C040A-90TU 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
Atmel Corporation (now part of Microchip Technology) is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication devices.
The AT29C040A-90TU belongs to Atmel's 5V-only Flash memory product line, designed specifically for legacy industrial, computing, and communications systems requiring simple, robust, in-system reprogrammability without high-voltage circuitry.
FAQ
What is the maximum operating temperature range for the AT29C040A-90TU?
The AT29C040A-90TU is rated for industrial temperature operation from –40°C to +85°C. This range is confirmed in the DC and AC Operating Range section of the datasheet and applies to both read and program operations. Thermal derating is not required within this envelope, and the device maintains full 90 ns read timing and 10 ms sector program performance across the entire span.
Does the AT29C040A-90TU support true 5V-only programming without external voltage boosters?
Yes, the AT29C040A-90TU supports true 5V-only programming: all command sequences - including sector erase, byte load, software data protection enable/disable, and boot block lockout - execute using only the VCC supply (5V ±10%). No external 12V or charge-pump circuitry is needed, distinguishing it from earlier EPROM or multi-voltage Flash devices.
How does the boot block lockout feature work on the AT29C040A-90TU?
The AT29C040A-90TU provides two independent 16K-byte boot blocks - one at addresses 0x00000–0x03FFF and another at 0x7C000–0x7FFFF. Each can be permanently locked via a 7-command algorithm. Once locked, those regions cannot be erased or programmed, and chip-erase is disabled. Lock status is readable via software product identification mode at addresses 0x00002H (lower block) and 0x7FFF2H (upper block).
Can the AT29C040A-90TU be used as a drop-in replacement for standard EPROMs like the 27C040?
No, the AT29C040A-90TU is not a pin-compatible or functional drop-in replacement for the 27C040 EPROM. While both are 4 Mbit × 8 and share similar pinouts (A0–A18, I/O0–I/O7, CE/OE/WE), the AT29C040A-90TU requires specific command sequences for programming and features DATA polling/Toggle Bit status reporting - unlike the 27C040's UV-erase and single-pulse programming model.
What methods are available to detect program completion on the AT29C040A-90TU?
The AT29C040A-90TU provides two hardware-confirmed methods: DATA polling (reading I/O7 returns complement of loaded data until completion, then true data) and Toggle Bit (I/O6 toggles between 0 and 1 during programming, then stabilizes). Both methods are valid at any time during the 10 ms sector program cycle and require no additional timing margins beyond tWC specification.
AT29C040A-90TU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-TFSOP (0.724", 18.40mm Width)
- Packaging:
- Tray
- 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:
- -
- Write Cycle Time - Word, Page:
- 10ms
- Access Time:
- 90 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-TSOP
AT29C040A-90TU FAQ
1.How can I place an order for AT29C040A-90TU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C040A-90TU 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 AT29C040A-90TU reliable?
The price and inventory of AT29C040A-90TU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C040A-90TU is usually 5 days.
3.What payment methods are accepted for AT29C040A-90TU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C040A-90TU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C040A-90TU?
AT29C040A-90TU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C040A-90TU 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 AT29C040A-90TU?
For technical support, including AT29C040A-90TU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C040A-90TU requirements.
6.How does Aetrix verify that AT29C040A-90TU is sourced from the original manufacturer or authorized distributors?
All AT29C040A-90TU 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 AT29C040A-90TU meets industry standards.
7.What is the process for return or replacement of AT29C040A-90TU?
All AT29C040A-90TU units undergo pre-shipment inspection (PSI). If there is an issue with AT29C040A-90TU, 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 AT29C040A-90TU part is unused and in its original packaging.
Return procedure for AT29C040A-90TU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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