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Microchip Technology AT29C040A-12JU-T
- Part No.:
- AT29C040A-12JU-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C040A-12JU-T.pdf
- Description:
- IC FLASH 4MBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,754
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Product details
Overview
AT29C040A-12JU-T from Atmel is a 4-megabit (512K × 8) 5-volt-only Flash memory IC organized in 2048 sectors of 256 bytes each, featuring 120 ns read access time, sector-based reprogramming, and dual 16K-byte boot blocks with independent programming lockout - used for firmware storage and system boot code in embedded controllers and industrial microcontroller systems.
For engineers reviewing the AT29C040A-12JU-T datasheet, AT29C040A-12JU-T pinout, AT29C040A-12JU-T application, or AT29C040A-12JU-T equivalent, key selection criteria include sector erase granularity, 5V-only operation without high-voltage programming, DATA polling/toggle-bit program status detection, hardware/software data protection, and PLCC-32 packaging compatibility with legacy board layouts.
Technical Context
The AT29C040A-12JU-T implements a sector-program architecture where each 256-byte sector is erased and programmed in a single internal cycle using an on-chip timer; address and data latches free the bus during programming. It supports both hardware- and software-controlled data protection, including VCC sense (inhibit below 3.8 V), 5 ms power-on delay, and a three-byte unlock sequence for write enable.
Boot block lockout operates independently on two 16K-byte regions (lowest and highest addresses), activated via a seven-command algorithm; once enabled, those blocks become permanently read-only and disable chip-erase functionality. Product identification mode (manufacturer code 1Fh, device code A4h) is accessible via hardware or software entry, enabling density-agnostic system firmware.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (524,288 × 8), sufficient for full firmware images in 8-bit/16-bit microcontrollers |
| Read Access Time | 120 ns max - determines worst-case instruction fetch latency in tightly timed embedded boot sequences |
| Sector Size | 256 bytes - enables fine-grained firmware updates without erasing entire memory space |
| Program Cycle Time | 10 ms per sector - defines minimum time between successive sector writes in field-upgrade routines |
| VCC Supply | 5 V ±10% - eliminates need for dedicated programming voltage rails in system design |
| Endurance | >10,000 program/erase cycles per sector - supports long-term field update capability in industrial equipment |
| Standby Current | 100 µA CMOS - enables low-power retention in battery-backed or energy-constrained applications |
Pinout & Package
AT29C040A-12JU-T is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC), JEDEC MS-016 variation AE compliant, with 1.27 mm pitch, 12.45 mm × 14.95 mm body, and lead coplanarity ≤0.102 mm - suitable for through-hole and surface-mount reflow assembly with standard PLCC sockets or pads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A18 | Address Inputs | 19-bit address bus supporting full 524,288-word addressing; A0–A7 select byte within 256-byte sector |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface for read, byte load, and program data; supports DATA polling on I/O7 and toggle-bit detection on I/O6 |
| CE | Chip Enable | Active-low chip select; must be stable before address setup; inhibits program if held high |
| OE | Output Enable | Active-low output control; high-Z when asserted high; required high during byte load/program cycles |
| WE | Write Enable | Active-low write strobe; controls latching of address/data during byte load; toggling initiates toggle-bit mode |
| NC | No Connect | Pin 16 (PLCC top view) - no internal connection; must remain unconnected per design |
| VCC | Power Supply | +5 V ±10% supply; powers core logic and I/O drivers; VCC sense circuitry disables programming if <3.8 V |
| GND | Ground | Reference return for all signals and power; decoupling capacitor placement critical for noise immunity during sector programming |
Key Features
| Feature | Design Value |
|---|---|
| Single-cycle sector erase & program | Eliminates external erase timing control; internal timer automates full sector reprogramming after 256-byte load |
| Hardware data protection | VCC sense + 5 ms power-on delay + WE/CE/OE inhibit logic prevents accidental writes during power ramp or noise events |
| Software data protection | Three-byte unlock sequence (AAh/55h/A0h) required before any sector program - prevents unintended firmware corruption |
| Dual boot block lockout | Independent 16K-byte lockout for lower/higher address regions ensures secure bootloader persistence across firmware updates |
| DATA polling & toggle-bit status | I/O7 complement read or I/O6 toggling provides real-time, bus-compatible program completion detection without external timers |
Applications
| Industrial PLC Firmware Storage | Legacy Embedded Controller Boot Memory |
|---|---|
Use Scenario: Storing ladder logic firmware and configuration parameters in programmable logic controllers operating in harsh factory environments with wide temperature swings. IC Role / Device Role / Timing Role: Nonvolatile boot memory holding initialization code and runtime firmware; accessed at power-on reset with 120 ns read timing to meet deterministic boot deadlines. Use Value: Sector-level updates allow field patches without full memory reflash; 10,000-cycle endurance supports decades of maintenance cycles in unattended installations. | Use Scenario: Providing boot code and BIOS extensions for 8051- and Z80-based industrial control boards where legacy PLCC footprints constrain redesign. IC Role / Device Role / Timing Role: Primary firmware ROM replacement; operates as drop-in EPROM-equivalent with identical CE/OE/WE control timing and 5V-only interface. Use Value: PLCC-32 package matches existing socketed EPROM layouts; boot block lockout secures startup vectors against overwrite during application code updates. |
| Medical Device Configuration Storage | Automated Test Equipment Calibration Data |
Use Scenario: Retaining calibration coefficients, safety thresholds, and user preferences in Class II medical instruments requiring traceable, tamper-resistant nonvolatile storage. IC Role / Device Role / Timing Role: Secure configuration memory with hardware/software write protection; accessed only during service mode or power-up self-test. Use Value: Dual lockout and software protection prevent unauthorized or accidental modification; 100 µA standby current minimizes battery drain in portable units. | Use Scenario: Storing instrument-specific calibration constants and test pattern tables in benchtop ATE platforms where firmware and calibration data must coexist in same memory space. IC Role / Device Role / Timing Role: Shared memory resource partitioned into protected boot region and field-updatable calibration sectors. Use Value: 256-byte sector granularity enables atomic updates of individual sensor calibration sets without disturbing adjacent test algorithms or UI assets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT29C040-12JU | No dash suffix; identical electrical specs and pinout; same PLCC-32 package and 120 ns timing | Same use cases; minor ordering code variant - not recommended for new designs per Atmel documentation | Select AT29C040A-12JU-T for guaranteed green (Pb/Halide-free) compliance and documented lifecycle support |
| MX29LV400CBTI-12G | 3V/5V tolerant, 120 ns access, 4 Mbit, TSOP-48; lacks boot block lockout and software protection features | Suitable for cost-sensitive 3.3V systems but requires level-shifting or voltage regulation for 5V buses; no built-in security mechanisms | Choose only if migrating to 3.3V operation and accepting reduced firmware protection; not pin-compatible |
Compared with AT29C040-12JU, the AT29C040A-12JU-T adds Pb/Halide-free packaging and updated qualification; versus MX29LV400CBTI-12G, it retains 5V-native operation and integrated security but uses PLCC instead of TSOP - critical for legacy board compatibility and robustness in vibration-prone environments.
Availability
AT29C040A-12JU-T is available at Aetrix Electronics and suitable for industrial PLCs, legacy embedded controller upgrades, medical device calibration storage, and automated test equipment requiring stable component supply with long-lifecycle assurance.
Supply support for AT29C040A-12JU-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
Atmel Corporation, now part of Microchip Technology, designed high-reliability nonvolatile memory and microcontroller solutions for industrial, automotive, and communications markets before its 2016 acquisition.
The AT29C040A belongs to Atmel's 5-volt-only Flash family targeting in-system reprogrammability in legacy 5V embedded systems - emphasizing sector granularity, hardware/software write protection, and PLCC packaging for backward compatibility.
FAQ
What is the maximum read access time specified for the AT29C040A-12JU-T?
The AT29C040A-12JU-T has a maximum read access time of 120 ns, as confirmed by its ordering code suffix "-12" and AC Read Characteristics table. This value represents the worst-case delay from address valid or CE/OE assertion to valid data on I/O0–I/O7 under industrial temperature range (–40°C to +85°C) and 5 V ±10% supply. The AT29C040A-12JU-T meets this specification without requiring external wait-state generation in most 8-bit microcontroller interfaces.
Does the AT29C040A-12JU-T support in-system programming without high-voltage supplies?
Yes, the AT29C040A-12JU-T supports full in-system reprogramming using only a single 5 V ±10% supply - no external 12 V or 21 V programming voltage is required. Its sector-based algorithm uses internally generated high-voltage pulses triggered by standard 5 V command sequences (e.g., AAh/55h/A0h), making it compatible with standard 5 V system buses and eliminating need for dedicated programming hardware beyond a microcontroller GPIO interface.
How does the boot block lockout feature work on the AT29C040A-12JU-T?
The AT29C040A-12JU-T contains two independent 16K-byte boot blocks - one at the lowest addresses (00000h–03FFFh) and one at the highest (7C000h–7FFFFh). Lockout is enabled per block via a seven-command software algorithm; once activated, that block becomes permanently read-only and immune to sector erase or program operations. Critically, enabling lockout on either block disables the global chip-erase function, ensuring bootloader integrity across firmware updates.
Can the AT29C040A-12JU-T be used as a direct replacement for standard EPROMs like the 27C040?
The AT29C040A-12JU-T is functionally compatible with 27C040 EPROMs in read mode - sharing identical pinout (PLCC-32), address/data bus behavior, and CE/OE/WE control timing - but differs critically in write methodology: it requires sector-based programming with software unlock sequences rather than UV erasure. As a result, it serves as a drop-in read replacement but demands firmware-level adaptation for in-system updates; no hardware changes are needed for read-only legacy systems.
What methods does the AT29C040A-12JU-T provide to detect program completion?
The AT29C040A-12JU-T offers two hardware-supported program status detection methods: DATA polling (reading I/O7 returns complement of loaded data until completion, then true data) and toggle-bit detection (I/O6 toggles between 0 and 1 during programming, then stabilizes). Both operate asynchronously over the standard data bus, require no external clocks or timers, and can be initiated at any point during the 10 ms sector program cycle - enabling efficient CPU polling or interrupt-driven firmware flow control.
AT29C040A-12JU-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:
- -
- Write Cycle Time - Word, Page:
- 10ms
- Access Time:
- 120 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-12JU-T FAQ
1.How can I place an order for AT29C040A-12JU-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C040A-12JU-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 AT29C040A-12JU-T reliable?
The price and inventory of AT29C040A-12JU-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C040A-12JU-T is usually 5 days.
3.What payment methods are accepted for AT29C040A-12JU-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C040A-12JU-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C040A-12JU-T?
AT29C040A-12JU-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C040A-12JU-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 AT29C040A-12JU-T?
For technical support, including AT29C040A-12JU-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C040A-12JU-T requirements.
6.How does Aetrix verify that AT29C040A-12JU-T is sourced from the original manufacturer or authorized distributors?
All AT29C040A-12JU-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 AT29C040A-12JU-T meets industry standards.
7.What is the process for return or replacement of AT29C040A-12JU-T?
All AT29C040A-12JU-T units undergo pre-shipment inspection (PSI). If there is an issue with AT29C040A-12JU-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 AT29C040A-12JU-T part is unused and in its original packaging.
Return procedure for AT29C040A-12JU-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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