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Microchip Technology AT29C040A-90JU
- Part No.:
- AT29C040A-90JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C040A-90JU.pdf
- Description:
- IC FLASH 4MBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,571
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Product details
Overview
AT29C040A-90JU from Atmel is a 4-Mbit (512K × 8) 5V-only Flash memory IC used for in-system reprogrammable nonvolatile storage in embedded boot code and firmware applications. It features 90 ns read access time, 256-byte sector erase/program architecture, hardware and software data protection, and two 16K-byte boot blocks with independent lockout. Designed for industrial temperature range (−40°C to +85°C), it operates on single 5V ±10% supply.
For engineers reviewing the AT29C040A-90JU datasheet, AT29C040A-90JU pinout, AT29C040A-90JU application, or AT29C040A-90JU equivalent, key selection criteria include sector-based programming timing (10 ms), DATA polling and toggle-bit end-of-write detection, boot block lockout behavior, and PLCC-32 package compatibility with legacy 5V microcontroller interfaces.
Technical Context
The AT29C040A-90JU implements a sector-erase Flash architecture where each of 2048 sectors (256 bytes each) is erased and programmed in a single internal cycle. Address latching occurs on falling CE or WE edges, with data latched on the subsequent rising edge - enabling bus release during load phases.
It supports dual data-protection layers: hardware-level VCC sense (inhibit below 3.8 V), noise filtering (<15 ns pulse rejection), and software-controlled protection requiring three-byte command sequences (AAh/55h/A0h) before any sector program. Boot block lockout uses a seven-command enable sequence and disables chip erase when activated.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512K × 8), organized as 2048 sectors × 256 bytes - enables granular firmware updates without full-chip erase. |
| Read Access Time | 90 ns - meets timing requirements for 11 MHz bus interfaces with zero wait states. |
| Sector Program Time | 10 ms - defines minimum interval between successive sector writes; critical for bootloader timeout design. |
| VCC Supply | 5 V ±10% - eliminates need for charge pumps or auxiliary voltage rails in 5V systems. |
| Endurance | >10,000 write/erase cycles per sector - supports field firmware upgrades over product lifetime. |
| Standby Current | 100 µA CMOS - enables low-power suspend modes in battery-backed or energy-sensitive systems. |
| Operating Temp | −40°C to +85°C - qualified for industrial-grade embedded control and communications equipment. |
Pinout & Package
AT29C040A-90JU is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC), JEDEC MS-016 variation AE compliant, with 1.27 mm pitch and 12.45 mm × 14.95 mm body size. Pin 1 identifier is a corner notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A18 | Address Inputs | 19-bit address bus supporting full 512K-word addressing; A0–A7 select byte within sector, A8–A18 select sector. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface compatible with standard microprocessor data buses; supports byte load and DATA polling on I/O7. |
| CE | Chip Enable | Active-low chip select; must be low for read, program, or identification modes; high disables outputs and enters standby. |
| OE | Output Enable | Active-low output control; used with CE to gate read data; high forces outputs to high-impedance state. |
| WE | Write Enable | Active-low control for byte load and program initiation; toggling WE (with OE high) loads data or triggers internal programming timer. |
| VCC | Power Supply | +5 V ±10% supply input; internal VCC sense circuitry inhibits programming if voltage drops below ~3.8 V. |
| GND | Ground | Reference return path for all signals and power; decoupling capacitor required near VCC pin. |
| NC | No Connect | Unbonded pin; must remain unconnected per datasheet - no external pull-up/down or routing. |
Key Features
| Feature | Design Value |
|---|---|
| Single 5V Reprogramming | Eliminates need for 12V programming supplies - simplifies PCB layout and reduces BOM count in 5V systems. |
| 256-Byte Sector Architecture | Enables partial firmware updates without erasing unrelated code sections - improves field upgrade safety and speed. |
| DATA Polling & Toggle Bit | Allows real-time program completion detection via I/O7 complement or I/O6 toggling - avoids fixed delays and improves system responsiveness. |
| Dual Boot Block Lockout | Two independent 16K-byte regions (first/last) can be permanently write-protected - secures bootloaders against accidental overwrite. |
| Hardware + Software Data Protection | VCC sensing, noise filtering, and 3-byte unlock sequence prevent unintended writes during power transients or EMI events. |
Applications
| Industrial PLC Firmware Storage | Legacy Embedded System Boot Code |
|---|---|
Use Scenario: Storing ladder logic firmware and configuration data in programmable logic controllers operating in factory-floor environments with wide temperature swings and electrical noise. IC Role / Device Role / Timing Role: Nonvolatile program memory holding boot firmware and runtime application code; accessed at 90 ns for deterministic scan-cycle timing. Use Value: Sector-level erase allows incremental firmware patches without disrupting operational logic; boot block lockout prevents corruption of startup routines during field updates. | Use Scenario: Hosting BIOS or bootloader code in older x86 or 8051-based industrial computers where space-constrained designs require reliable, pin-compatible Flash replacement. IC Role / Device Role / Timing Role: Direct EPROM drop-in replacement providing in-system reprogrammability; matches 27C040 timing envelope with identical 32-pin PLCC footprint. Use Value: Eliminates need for UV-erasable EPROM sockets and programmers; 5V-only operation removes high-voltage generation circuitry from motherboard design. |
| Communications Equipment Configuration | Medical Device Calibration Data |
Use Scenario: Storing protocol stacks, MAC addresses, and calibration constants in network switches and modems deployed in telecom infrastructure cabinets. IC Role / Device Role / Timing Role: Configuration memory mapped into CPU address space; accessed during power-on initialization and runtime parameter lookup. Use Value: Hardware data protection ensures integrity during brown-out conditions; 10,000-cycle endurance supports periodic recalibration over multi-year service life. | Use Scenario: Retaining sensor calibration coefficients and safety-critical firmware in portable diagnostic devices subject to strict regulatory traceability requirements. IC Role / Device Role / Timing Role: Secure nonvolatile storage for FDA-compliant device parameters; boot block lockout enforces write-protection of certified code sections. Use Value: Software data protection prevents unauthorized modification; green (Pb/Halide-free) packaging satisfies RoHS compliance for medical electronics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV040B-90JC | 4 Mbit, 90 ns, 3.3V core with 5V I/O tolerance; requires VPP = 12V for sector erase. | Not pin-compatible; different voltage domain and timing - requires level-shifting and modified reset sequencing. | Choose only if migrating to 3.3V systems with legacy 5V bus interface; not suitable for direct AT29C040A-90JU replacement. |
| MX29LV040CTTI-90G | 4 Mbit, 90 ns, 3.0V–3.6V supply; no 5V operation; supports CFI query mode. | Requires full 3.3V system redesign; lacks boot block lockout and software protection commands. | Consider for new low-voltage designs prioritizing CFI compatibility and lower active current; incompatible with existing 5V AT29C040A-90JU layouts. |
Compared with AM29LV040B-90JC and MX29LV040CTTI-90G, the AT29C040A-90JU uniquely delivers true 5V-only operation with integrated boot block security and software data protection - making it the only viable option for maintaining legacy 5V embedded systems without hardware redesign.
Availability
AT29C040A-90JU is available at Aetrix Electronics and suitable for industrial PLCs, legacy embedded boot systems, telecom equipment configuration, medical device calibration storage, and automotive diagnostic tools requiring stable component supply across extended lifecycle demands.
Supply support for AT29C040A-90JU 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 fabless semiconductor company specializing in microcontrollers, Flash memory, and secure authentication ICs for industrial, automotive, and consumer applications.
The AT29C040A belongs to Atmel's 5V-only Flash memory product line, designed specifically to replace UV-erasable EPROMs in legacy systems while enabling in-circuit firmware updates without high-voltage programming hardware.
FAQ
What is the maximum operating temperature range for the AT29C040A-90JU?
The AT29C040A-90JU is rated for industrial temperature operation from −40°C to +85°C. This range is validated per the manufacturer's DC and AC operating specifications and applies to all functional modes including read, program, and standby. The PLCC package's thermal characteristics support reliable operation under sustained ambient conditions within this envelope, provided adequate PCB copper pour and airflow are maintained.
Does the AT29C040A-90JU require external high-voltage programming signals?
No, the AT29C040A-90JU does not require external high-voltage programming signals. It is a 5-volt-only Flash memory: all sector erase and program operations are executed using standard 5V logic levels on CE, WE, and OE pins. Internal charge pumps generate necessary voltages, eliminating the need for 12V VPP supplies or dedicated programming hardware - a key distinction from earlier EPROM or EEPROM technologies.
How does the boot block lockout feature work on the AT29C040A-90JU?
The AT29C040A-90JU provides two independent 16K-byte boot blocks - one at the lowest 16K (addresses 00000H–03FFFH) and one at the highest 16K (7C000H–7FFFFH). Lockout is enabled via a seven-command software sequence; once set, those blocks become permanently read-only. Reading address 00002H returns FEh (unlocked) or FFh (locked) for the lower block; 7FFF2H indicates upper block status. Chip erase is disabled if either block is locked.
Can the AT29C040A-90JU be used as a direct replacement for the 27C040 EPROM?
Yes, the AT29C040A-90JU is designed as a functional and pin-compatible replacement for the 27C040 EPROM in 32-pin PLCC packages. It matches the same 512K × 8 organization, 90 ns access time, and parallel interface timing. Unlike the 27C040, it supports in-system reprogramming via standard 5V signals and includes hardware/software write protection - enabling field firmware updates without removing the device.
What methods does the AT29C040A-90JU provide to detect program completion?
The AT29C040A-90JU offers two hardware-supported methods: DATA polling and Toggle Bit. During programming, reading the last loaded byte returns the complement of data on I/O7 until completion, then true data. Alternatively, I/O6 toggles between 0 and 1 during the internal program cycle and stabilizes upon completion. Both methods allow real-time detection without fixed delay loops - essential for deterministic embedded system timing.
AT29C040A-90JU 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:
- -
- 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-PLCC (13.97x11.43)
AT29C040A-90JU FAQ
1.How can I place an order for AT29C040A-90JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C040A-90JU 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-90JU reliable?
The price and inventory of AT29C040A-90JU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C040A-90JU is usually 5 days.
3.What payment methods are accepted for AT29C040A-90JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C040A-90JU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C040A-90JU?
AT29C040A-90JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C040A-90JU 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-90JU?
For technical support, including AT29C040A-90JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C040A-90JU requirements.
6.How does Aetrix verify that AT29C040A-90JU is sourced from the original manufacturer or authorized distributors?
All AT29C040A-90JU 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-90JU meets industry standards.
7.What is the process for return or replacement of AT29C040A-90JU?
All AT29C040A-90JU units undergo pre-shipment inspection (PSI). If there is an issue with AT29C040A-90JU, 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-90JU part is unused and in its original packaging.
Return procedure for AT29C040A-90JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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