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Microchip Technology AT29LV040A-20JC
- Part No.:
- AT29LV040A-20JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29LV040A-20JC.pdf
- Description:
- IC FLASH 4MBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,691
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Product details
Overview
AT29LV040A-20JC from Atmel is a 4-Mbit (512K × 8) 3.3V-only Flash memory IC organized in 2048 sectors of 256 bytes each, featuring 150 ns read access time, 20 ms max sector program cycle, and dual 16K-byte boot blocks with independent programming lockout. It operates across commercial temperature range (0°C to 70°C) in a 32-lead PLCC package and is used for firmware storage and in-system reprogramming in embedded controllers.
For engineers reviewing the AT29LV040A-20JC datasheet, AT29LV040A-20JC pinout, AT29LV040A-20JC application, or AT29LV040A-20JC equivalent, key selection considerations include sector-based reprogrammability, software data protection sequence (AAh/55h/A0h), DATA polling on I/O7 for program completion detection, and boot block lockout support for secure boot code retention.
Technical Context
The AT29LV040A-20JC implements sector-erase-and-program architecture with internal address/data latches for 256-byte loads, eliminating external buffering during programming. Its software-controlled write protocol requires three specific command cycles before any sector load, and supports both WE- and CE-controlled byte loading with 150 µs inter-byte timing window.
Hardware protections include VCC sense (<1.8V inhibit), 10 ms power-on delay, noise filtering (<15 ns pulse rejection), and active control-line gating (OE low/CE high/WE high disables programming). Input levels tolerate 0–5.5V on address/control pins while I/O lines are limited to 0–3.6V, enabling mixed-voltage system interfacing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512K × 8), enabling full firmware image storage for mid-complexity microcontrollers |
| Read Access Time | 200 ns max (tACC), compatible with 5 MHz bus timing without wait states |
| Supply Voltage | 3.3 V ± 0.3 V only - eliminates need for 5V or 12V programming voltages |
| Active Current | 15 mA max at 5 MHz - supports low-power operation in battery-backed systems |
| Standby Current | 40 µA CMOS standby - enables ultra-low leakage during sleep modes |
| Sector Size | 256 bytes per sector - balances granularity for partial updates and erase efficiency |
| Endurance | 10,000 program/erase cycles per sector - sufficient for field firmware upgrades over product lifetime |
Pinout & Package
AT29LV040A-20JC is housed in a 32-lead Plastic J-Leaded Chip Carrier (PLCC) package with standard JEDEC MS-016, Variation AE footprint. Pin 1 identifier is marked by a corner notch; leads are gull-wing shaped with 1.27 mm pitch.
| 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 |
| CE | Chip Enable | Active-low chip select; must be low for read/write; high forces outputs to high-Z and inhibits programming |
| OE | Output Enable | Active-low output control; used with CE for bus contention management during reads |
| WE | Write Enable | Active-low write strobe; controls byte loading during sector programming; OE must be high when WE and CE are both low |
| I/O0–I/O7 | Bi-directional Data Bus | 8-bit data path for read and write; I/O7 provides DATA polling bit; I/O6 provides toggle-bit status |
| NC | No Connect | Pin 13 (PLCC top view) is unconnected - no routing or termination required |
| VCC | Power Supply | 3.3V supply input; must stabilize ≥20 ms after power-on before first operation |
| GND | Ground | Reference plane for all signals and power; pin 16 (PLCC top view) |
Key Features
| Feature | Design Value |
|---|---|
| Software Data Protection | Three-command sequence (AAh→55h→A0h) required before every sector program - prevents accidental writes during noise events or power transients |
| Boot Block Lockout | Two independent 16K-byte blocks (first and last) can be permanently locked via 7-command enable algorithm - secures bootloader code against corruption |
| DATA Polling on I/O7 | Complement of loaded data appears on I/O7 during programming; true data returns upon completion - enables host CPU to poll instead of using fixed delays |
| Toggle Bit on I/O6 | I/O6 toggles between 0/1 during program/erase; stops toggling when complete - provides alternate asynchronous status indication |
| Single-Cycle Sector Reprogram | Internal erase + program executed automatically after 256-byte load - simplifies firmware update logic and reduces host-side timing overhead |
Applications
| Industrial PLC Firmware Storage | Automotive Instrument Cluster Boot Code |
|---|---|
|
Use Scenario: Storing and updating ladder logic firmware in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile firmware storage with in-system reprogrammability; retains code during power loss and supports field updates via RS-485 interface. Use Value: 2048-sector granularity allows partial updates without erasing entire firmware; 40 µA standby current minimizes backup battery drain during maintenance mode. |
Use Scenario: Holding boot loader and critical initialization routines in automotive digital instrument clusters operating across -40°C to +85°C. IC Role / Device Role / Timing Role: Secure boot memory with hardware-protected lockout; stores verified startup code that initializes CAN controller and display driver. Use Value: Dual boot blocks allow separate locking of primary and fallback boot images; 10,000-cycle endurance supports dealer-level calibration updates over vehicle lifetime. |
| Medical Device Configuration Memory | Networking Equipment Image Repository |
|
Use Scenario: Retaining device-specific calibration parameters and safety-critical configuration profiles in portable diagnostic equipment. IC Role / Device Role / Timing Role: Parameter storage with tamper-resistant programming; accessed during power-up to configure ADC gain, sensor offsets, and alarm thresholds. Use Value: Software data protection prevents unintended parameter changes during ESD events; 150 ns read speed ensures fast boot without delaying clinical readiness. |
Use Scenario: Hosting multiple firmware images (primary, backup, recovery) in enterprise switches and routers for fail-safe upgrades. IC Role / Device Role / Timing Role: Multi-image flash repository; supports atomic swap between active and updated images using sector-level erase boundaries. Use Value: 256-byte sector size enables precise image partitioning; DATA polling allows deterministic upgrade timing without relying on worst-case 20 ms delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SST39VF400A-70-4C-NHE | 4 Mbit, 70 ns access, 3.3V supply, TSOP-48 package - faster read but larger footprint and no boot block lockout | Lacks dedicated boot block protection; requires external logic or firmware to emulate lockout behavior | Choose when raw read speed >200 ns is required and board layout accommodates 48-pin TSOP |
| MX29LV400CBTI-70G | 4 Mbit, 70 ns access, 3.0–3.6V supply, 48-pin TSOP - includes CFI compliance and single-power-byte-write mode | Supports Common Flash Interface commands; lacks identical 256-byte sector structure and uses different unlock sequence | Prefer for designs requiring standardized CFI drivers or where byte-level writes (not sector-only) are needed |
Compared with SST39VF400A-70-4C-NHE and MX29LV400CBTI-70G, the AT29LV040A-20JC offers tighter integration of boot block security and simpler sector programming flow, making it optimal for cost-sensitive, space-constrained embedded systems where firmware integrity is prioritized over maximum read speed.
Availability
AT29LV040A-20JC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, automotive instrument cluster boot code, and medical device configuration memory requiring stable component supply and long-term obsolescence management.
Supply support for AT29LV040A-20JC 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 AT29LV040A-20JC belongs to Atmel's legacy 3.3V Flash memory product line, designed specifically for in-system programmable firmware storage in resource-constrained embedded systems with emphasis on reliability, low voltage operation, and secure boot capability.
FAQ
What is the correct software unlock sequence to program the AT29LV040A-20JC?
The AT29LV040A-20JC requires a three-step software unlock sequence before any sector programming: write data AAh to address 5555h, then 55h to address 2AAAh, then A0h to address 5555h. This sequence must be repeated before each sector load. The AT29LV040A-20JC does not accept programming commands without this exact sequence, and power transitions do not reset the unlock state - ensuring robustness against brown-out conditions.
How does the boot block lockout feature work on the AT29LV040A-20JC?
The AT29LV040A-20JC contains two 16K-byte boot blocks - one at the lowest addresses (00000h–03FFFh) and one at the highest (FC000h–FFFFFh). Each can be independently locked using a seven-command enable algorithm. Once activated, the locked block cannot be erased or programmed, even by chip erase. The AT29LV040A-20JC supports software detection of lock status via reads from addresses 00002h (lower block) and 7FFF2h (upper block).
Can the AT29LV040A-20JC be used in a 5V system environment?
The AT29LV040A-20JC is a 3.3V-only device: its VCC must be 3.3V ± 0.3V, and I/O lines tolerate only up to 3.6V. While address and control inputs (A0–A18, CE, OE, WE) accept 0–5.5V logic levels, the I/O0–I/O7 pins are strictly 3.3V-tolerant. Direct connection to 5V buses will damage the AT29LV040A-20JC. Level-shifting circuitry is required for interoperability with 5V microcontrollers.
What is the difference between DATA polling and the toggle bit on the AT29LV040A-20JC?
DATA polling uses I/O7: during programming, it outputs the complement of the last loaded byte; when programming completes, it outputs true data. The toggle bit uses I/O6: it alternates between 0 and 1 during programming and stabilizes upon completion. Both methods allow host software to detect program end asynchronously. The AT29LV040A-20JC supports either method - polling is simpler for single-byte checks; toggle-bit is more robust under bus contention.
Is the AT29LV040A-20JC still recommended for new designs?
No - the AT29LV040A-20JC is marked "Not recommended for New Designs" in the official Atmel documentation (Rev. 0334G–FLASH–2/05). It has been superseded by higher-density, lower-power, and RoHS-compliant alternatives such as the AT45DB series or Microchip's SST series. However, the AT29LV040A-20JC remains supported for legacy repair, replacement, and long-lifecycle industrial programs with established qualification.
AT29LV040A-20JC 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:
- 20ms
- Access Time:
- 200 ns
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT29LV040A-20JC FAQ
1.How can I place an order for AT29LV040A-20JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29LV040A-20JC 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 AT29LV040A-20JC reliable?
The price and inventory of AT29LV040A-20JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29LV040A-20JC is usually 5 days.
3.What payment methods are accepted for AT29LV040A-20JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29LV040A-20JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29LV040A-20JC?
AT29LV040A-20JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29LV040A-20JC 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 AT29LV040A-20JC?
For technical support, including AT29LV040A-20JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29LV040A-20JC requirements.
6.How does Aetrix verify that AT29LV040A-20JC is sourced from the original manufacturer or authorized distributors?
All AT29LV040A-20JC 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 AT29LV040A-20JC meets industry standards.
7.What is the process for return or replacement of AT29LV040A-20JC?
All AT29LV040A-20JC units undergo pre-shipment inspection (PSI). If there is an issue with AT29LV040A-20JC, 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 AT29LV040A-20JC part is unused and in its original packaging.
Return procedure for AT29LV040A-20JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT29LV040A-20JC Tags
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