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Microchip Technology AT29C040A-12JU
- Part No.:
- AT29C040A-12JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29C040A-12JU.pdf
- Description:
- IC FLASH 4MBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,985
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Product details
Overview
AT29C040A-12JU from Atmel is a 4-Mbit (512K × 8) 5V-only Flash memory IC used for in-system firmware storage and boot code retention in embedded controllers. It features 90 ns read access time, 256-byte sector erase/program architecture, hardware/software data protection, and two 16K-byte boot blocks with independent lockout. It operates across -40°C to +85°C and supports DATA polling and toggle-bit program completion detection.
For engineers reviewing the AT29C040A-12JU datasheet, AT29C040A-12JU pinout, AT29C040A-12JU application, or AT29C040A-12JU equivalent, key selection criteria include sector-based reprogrammability, 5V-only operation without high-voltage programming, boot block lockout for secure startup code, CMOS standby current under 100 µA, and compatibility with legacy EPROM-style bus interfaces.
Technical Context
The AT29C040A-12JU implements a nonvolatile Flash PEROM architecture using Atmel's CMOS EEPROM process. It organizes 4 Mbits as 524,288 words × 8 bits, with 2048 sectors of 256 bytes each. Sector programming requires internal latching of address and data before automatic erase-and-program execution controlled by an on-chip timer.
It supports dual data-protection mechanisms: hardware-level VCC sensing (<3.8 V inhibits programming), noise filtering (<15 ns pulses ignored), and software-controlled 3-byte command sequence (AAh/55h/A0h) to enable/disable write protection. Boot block lockout is activated via a 7-command algorithm and disables chip erase when enabled.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512K × 8) - supports full firmware images for 8-bit microcontrollers |
| Read Access Time | 120 ns max - meets timing for 8 MHz Z80/8051 bus cycles with margin |
| Sector Size | 256 bytes - enables fine-grained firmware updates without full chip erase |
| Program Cycle Time | 10 ms per sector - deterministic update latency for field firmware patches |
| VCC Supply | 5 V ±10% - eliminates need for dedicated programming voltage rails |
| Standby Current | 100 µA CMOS - enables low-power hold mode in battery-backed systems |
| Endurance | >10,000 program/erase cycles per sector - supports frequent field upgrades |
| Operating Temp | -40°C to +85°C - qualified for industrial control and automotive under-hood ECUs |
Pinout & Package
AT29C040A-12JU 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 256-byte 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 to high-Z |
| OE | Output Enable | Active-low output control; used with CE to gate data reads and prevent bus contention |
| WE | Write Enable | Active-low control for byte loading and sector programming initiation; toggling triggers address/data latching |
| NC | No Connect | Unbonded pin; must remain unconnected per design - no pull-up/down or routing required |
| VCC | Power Supply | +5 V ±10% supply; powers core logic and array; internal VCC sense prevents programming below 3.8 V |
| GND | Ground | Reference return path for all signals and power; decoupling capacitor required within 1 cm of VCC/GND pins |
Key Features
| Feature | Design Value |
|---|---|
| Single 5V Reprogramming | Eliminates external VPP programming voltage circuitry - reduces BOM count and board space |
| 256-Byte Sector Architecture | Enables partial firmware updates without erasing unrelated code sections - improves field upgrade safety |
| Dual Boot Block Lockout | Two independent 16K-byte regions (lowest/highest addresses) can be permanently write-locked - secures bootloader integrity |
| DATA Polling & Toggle Bit | I/O7 complement and I/O6 toggling provide real-time, bus-compatible program completion status - avoids fixed delay timers |
| Hardware + Software Protection | VCC sensing, noise filtering, and 3-byte unlock sequence jointly prevent accidental writes during power transients or noise events |
| Green Pb/Halide-Free Packaging | Meets RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 3 - supports lead-free reflow assembly |
Applications
| Industrial PLC Firmware Storage | Automotive ECU Bootloader Memory |
|---|---|
Use Scenario: Storing ladder logic firmware and configuration parameters in programmable logic controllers with periodic field updates. IC Role / Device Role / Timing Role: Nonvolatile program memory mapped to microcontroller address space; provides 120 ns read access for real-time scan cycle execution. Use Value: Sector erase enables updating only modified function blocks without resetting entire control logic - minimizing machine downtime. | Use Scenario: Holding certified bootloader code in engine control units that must pass ISO 26262 ASIL-B functional safety requirements. IC Role / Device Role / Timing Role: Secure boot memory with independently lockable 16K-byte upper/lower blocks; accessed during cold start prior to main application load. Use Value: Boot block lockout prevents corruption of validated startup routines during over-the-air firmware updates - ensuring fail-safe boot behavior. |
| Medical Device Configuration Storage | Networking Equipment BIOS Retention |
Use Scenario: Retaining calibration tables, user preferences, and regulatory audit logs in portable diagnostic instruments with battery backup. IC Role / Device Role / Timing Role: Low-power nonvolatile storage interfaced to 8-bit MCU; draws only 100 µA in standby during battery-only operation. Use Value: CMOS standby current extends battery life beyond 5 years in always-on monitoring mode - meeting IEC 62304 power budget constraints. | Use Scenario: Storing boot firmware and hardware initialization code in managed Ethernet switches requiring remote firmware recovery. IC Role / Device Role / Timing Role: EPROM-compatible Flash memory mapped to CPU reset vector; supports hardware product identification via AAh/55h/90h command sequence. Use Value: Software product ID mode allows single PCB design to auto-detect density and apply correct sector size - simplifying multi-density BOM management. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV040B-120EC | 4 Mbit, 120 ns access, 3 V core with 5 V I/O tolerance; sector size 64 KB (not 256 B) | Larger erase granularity limits partial updates; requires 3 V supply rail | Choose if system already uses 3 V logic and tolerates full-sector erase for firmware patches |
| SST39VF040-120-4C-NHE | 4 Mbit, 120 ns, 3 V only; 512-byte sector size; lacks boot block lockout | No hardware-secured boot region; incompatible with legacy 5 V EPROM bus timing | Choose for cost-sensitive 3 V designs where bootloader security is handled externally |
Compared with AM29LV040B-120EC and SST39VF040-120-4C-NHE, the AT29C040A-12JU uniquely delivers 5 V-only operation with 256-byte sectors and dual boot block lockout - making it the only option for industrial systems requiring EPROM-pin-compatible, fine-grained, and tamper-resistant firmware storage.
Availability
AT29C040A-12JU is available at Aetrix Electronics and suitable for industrial PLCs, automotive ECUs, medical diagnostics, networking switches, and embedded controller firmware storage requiring stable component supply across extended lifecycles.
Supply support for AT29C040A-12JU 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, Flash memory, and secure authentication devices.
The AT29C040A-12JU belongs to Atmel's 5V-only Flash PEROM family, designed specifically for drop-in replacement of EPROMs in legacy embedded systems while enabling in-system reprogramming without high-voltage programming hardware.
FAQ
What is the maximum read access time specified for the AT29C040A-12JU?
The AT29C040A-12JU has a maximum read access time of 120 ns, as confirmed by its -12 speed grade designation and AC Read Characteristics table. This value applies across the full industrial temperature range (-40°C to +85°C) and ensures compatibility with 8 MHz microprocessor buses. The device also guarantees 90 ns access for the faster -90 variant, but the AT29C040A-12JU is rated at 120 ns.
Does the AT29C040A-12JU require high-voltage programming signals?
No, the AT29C040A-12JU does not require high-voltage programming signals. It is a 5-volt-only Flash memory: all programming operations - including sector erase and byte load - are executed using standard 5 V logic levels. Internal charge pumps generate necessary voltages, eliminating external VPP circuitry. This is explicitly stated in the datasheet's "5-volt Only Reprogramming" feature and "Description" section.
How many sectors does the AT29C040A-12JU contain, and what is the size of each sector?
The AT29C040A-12JU contains 2048 sectors, each sized at 256 bytes. This is documented in the "Sector Program Operation" feature list and confirmed in the "Description" section stating "2048 Sectors (256 Bytes/Sector)". The total memory capacity is 4 Mbit (512K × 8), and sector addressing uses A8–A18, yielding 2048 unique sector addresses.
Can the boot blocks of the AT29C040A-12JU be independently locked, and how is this done?
Yes, the AT29C040A-12JU has two 16K-byte boot blocks - one at the lowest addresses (0x00000–0x03FFF) and one at the highest (0x7C000–0x7FFFF) - and their programming lockout can be enabled independently. Activation requires a precise 7-command software algorithm (AAh/55h/80h/AAh/55h/40h followed by 00h at 0x00000H and FFh at 0x7FFFFH). Once set, lockout is permanent until device replacement.
What methods does the AT29C040A-12JU provide to detect the end of a program cycle?
The AT29C040A-12JU provides two hardware-supported methods: DATA polling on I/O7 (where the bit complements during programming and returns to true value upon completion) and toggle-bit detection on I/O6 (which alternates between 0 and 1 during programming and stabilizes afterward). Both methods allow real-time, bus-synchronous verification without fixed delays - critical for deterministic firmware update sequences in the AT29C040A-12JU.
AT29C040A-12JU 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:
- 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 FAQ
1.How can I place an order for AT29C040A-12JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C040A-12JU 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 reliable?
The price and inventory of AT29C040A-12JU 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 is usually 5 days.
3.What payment methods are accepted for AT29C040A-12JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C040A-12JU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C040A-12JU?
AT29C040A-12JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C040A-12JU 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?
For technical support, including AT29C040A-12JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C040A-12JU requirements.
6.How does Aetrix verify that AT29C040A-12JU is sourced from the original manufacturer or authorized distributors?
All AT29C040A-12JU 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 meets industry standards.
7.What is the process for return or replacement of AT29C040A-12JU?
All AT29C040A-12JU units undergo pre-shipment inspection (PSI). If there is an issue with AT29C040A-12JU, 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 part is unused and in its original packaging.
Return procedure for AT29C040A-12JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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