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Microchip Technology AT29C040A-90PC
- Part No.:
- AT29C040A-90PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-DIP (0.600", 15.24mm)
- Datasheet:
-
AT29C040A-90PC.pdf
- Description:
- IC FLASH 4MBIT PARALLEL 32DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,892
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Product details
Overview
AT29C040A-90PC from Atmel is a 4-Mbit (512K × 8) 5-volt-only Flash memory IC organized as 524,288 words by 8 bits, featuring 90 ns read access time, 256-byte sector architecture, and hardware/software data protection. It supports in-system reprogramming without high-voltage programming supplies and is used in embedded boot code storage, firmware updates, and industrial controller nonvolatile memory.
For engineers reviewing the AT29C040A-90PC datasheet, AT29C040A-90PC pinout, AT29C040A-90PC application, or AT29C040A-90PC equivalent, this page delivers verified timing specs, sector-program behavior, boot-block lockout logic, DATA polling and TOGGLE bit status detection methods, and real-world design implications for firmware integrity and system startup reliability.
Technical Context
The AT29C040A-90PC implements a sector-based Flash architecture with 2048 independent 256-byte sectors, enabling selective erase/program without full-chip erasure. Its internal address/data latches support burst loading of an entire sector before initiating automatic erase-and-program cycles controlled by an on-chip timer.
It integrates dual protection mechanisms: hardware-level VCC sensing (inhibits programming below 3.8 V), noise filtering (<15 ns pulse rejection), and software-controlled data protection requiring a three-byte unlock sequence (AAh/55h/A0h) before any sector program. Two 16K-byte boot blocks support independent lockout via a seven-command enable algorithm.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (524,288 × 8), sufficient for full BIOS/firmware images in legacy embedded systems |
| Read Access Time | 90 ns - enables direct execution from flash in 8-bit microcontroller systems without wait states |
| Sector Size | 256 bytes - balances granularity for field updates against overhead of sector management logic |
| Program Cycle Time | 10 ms per sector - defines minimum firmware update latency when rewriting critical boot code |
| VCC Supply | 5 V ±10% - eliminates need for dedicated programming voltage rails in host systems |
| Endurance | >10,000 write/erase cycles per sector - supports long-term field firmware revision in industrial controllers |
| Standby Current | 100 µA (CMOS) - ensures low power consumption during system sleep modes |
Pinout & Package
AT29C040A-90PC is packaged in a 32-lead, 0.600" wide plastic dual inline package (PDIP), designated 32P6 per Atmel's ordering information. Pin 1 is located at the left end of the top row when viewed with notch up.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A18 | Address Inputs | 19-bit address bus supporting full 524,288-word addressing; A8–A18 select sector, A0–A7 select byte within sector |
| CE | Chip Enable | Active-low chip select; must be low for read or program; high disables outputs and inhibits programming |
| OE | Output Enable | Active-low output control; used with CE to manage bus contention during reads; must be high during program cycles |
| WE | Write Enable | Active-low control for byte load and sector program initiation; timing-critical for 150 µs inter-byte loading window |
| I/O0–I/O7 | Bi-directional Data Bus | 8-bit parallel interface; I/O7 provides DATA polling status, I/O6 provides TOGGLE bit status during program/erase |
| GND / VCC | Power Terminals | Ground and 5 V supply pins; decoupling required near VCC to maintain stable operation during sector programming |
| NC | No Connect | Pin 32 is unconnected; must remain floating or tied to ground per layout best practice |
Key Features
| Feature | Design Value |
|---|---|
| 256-byte sector architecture | Enables targeted firmware patching without erasing unrelated application code or configuration data |
| Hardware data protection | VCC sense + 5 ms power-on delay prevents spurious writes during brown-out or power-up transients |
| Software data protection | Three-byte unlock sequence (AAh/55h/A0h) ensures intentional firmware updates and prevents accidental overwrites |
| Two 16K-byte boot blocks | Independent lockout supports dual-boot configurations or secure bootloader isolation from application code |
| DATA polling & TOGGLE bit | Real-time program completion detection without external timers or fixed delays, reducing system software complexity |
Applications
| Industrial PLC Firmware Storage | Legacy PC BIOS Memory |
|---|---|
Use Scenario: Storing ladder logic firmware and I/O configuration in programmable logic controllers operating in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile code storage with 90 ns read access enabling direct execution and fast diagnostics response. Use Value: Sector-level reprogramming allows field updates of control algorithms without replacing hardware or losing calibration data. |
Use Scenario: Holding BIOS initialization code and POST routines in desktop motherboards prior to transition to modern SPI Flash. IC Role / Device Role / Timing Role: Boot memory mapped at 0xFFFF0000; accessed via standard x86 memory bus with TTL/CMOS compatibility. Use Value: Dual 16K boot blocks let OEMs lock lower-address firmware while permitting upper-region option ROM updates. |
| Embedded Network Router Bootloader | Medical Device Configuration Storage |
Use Scenario: Hosting secure bootloader code that validates signed firmware images before loading into RAM on network edge devices. IC Role / Device Role / Timing Role: Read-only execution path during power-on; software data protection prevents unauthorized modification of boot sequence. Use Value: Boot block lockout ensures bootloader integrity across 10,000+ field update cycles, meeting IEC 62304 Class B requirements. |
Use Scenario: Retaining device calibration tables, user preferences, and regulatory audit logs in portable diagnostic equipment. IC Role / Device Role / Timing Role: Low-power CMOS standby mode (100 µA) preserves battery life between clinical sessions. Use Value: Hardware VCC sensing prevents corruption during battery swap or low-voltage conditions, ensuring data consistency. |
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 | 3 V core with 5 V I/O tolerance; 90 ns access but requires VPP = 12 V for program/erase | Not suitable for 5 V-only systems; requires additional voltage rail and level-shifting | Select only if migrating to lower-voltage platforms with existing 12 V programming infrastructure |
| SST39VF040-90-4C-NHE | 5 V-only, 90 ns, same 4 Mbit density and 256-byte sectors; supports byte-write without sector erase | Enables true byte-level updates; lacks boot block lockout and hardware VCC sensing | Prefer for applications needing frequent small-data updates but requiring external watchdog for power-fail safety |
Compared with AM29LV040B-90JC and SST39VF040-90-4C-NHE, the AT29C040A-90PC uniquely combines 5 V-only operation, integrated VCC-sense protection, and independently lockable boot blocks-making it optimal for cost-sensitive, legacy 5 V industrial systems where firmware integrity and simple power architecture are primary concerns.
Availability
AT29C040A-90PC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS replacement, and embedded bootloader applications requiring stable component supply and long-lifecycle support.
Supply support for AT29C040A-90PC 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 security ICs for industrial, automotive, and consumer applications.
The AT29C040A-90PC belongs to Atmel's 5-volt-only Flash family designed for in-system reprogrammability in legacy 5 V embedded systems where high-voltage programming infrastructure is unavailable or undesirable.
FAQ
What is the maximum operating temperature range for the AT29C040A-90PC?
The AT29C040A-90PC is rated for commercial operation from 0°C to +70°C. Its ordering code suffix "C" denotes the commercial temperature grade, confirmed in the official Atmel ordering information table. Industrial-grade variants (e.g., AT29C040A-90PI) support –40°C to +85°C, but the -90PC variant is strictly commercial. Always verify ambient thermal design margins when deploying AT29C040A-90PC in enclosed enclosures.
Does the AT29C040A-90PC require a high-voltage programming supply?
No, the AT29C040A-90PC operates with a single 5 V ±10% supply and does not require high-voltage programming inputs. All program and erase operations are initiated using standard 5 V logic levels and specific command sequences applied to the address and data bus. This eliminates the need for external VPP generators, simplifying board design and improving reliability compared to older EPROM or UV-erasable Flash devices.
How is sector programming performed on the AT29C040A-90PC?
Sector programming on the AT29C040A-90PC requires loading all 256 bytes of a target sector into internal latches via byte-load cycles, then initiating automatic erase-and-program using an internal timer. A8–A18 define the sector address; A0–A7 define the byte offset. Each byte must be loaded within 150 µs of the previous one. Once initiated, the 10 ms internal cycle completes autonomously, with completion signaled by DATA polling on I/O7 or TOGGLE bit behavior on I/O6.
Can the boot blocks of the AT29C040A-90PC be unlocked after programming lockout is enabled?
Yes, the boot block lockout feature on the AT29C040A-90PC is reversible. A documented seven-command algorithm (AAh/55h/80h/AAh/55h/40h followed by 00h at 00000H and FFh at 7FFFFH) disables lockout for either or both 16K-byte boot blocks. However, once disabled, the blocks remain unprotected until re-enabled. The AT29C040A-90PC datasheet confirms this reversibility and specifies exact timing and address requirements for each step.
What happens if a program command is issued to the AT29C040A-90PC without first enabling software data protection?
If software data protection is disabled (default state at shipment), the AT29C040A-90PC accepts standard sector program commands without unlock sequences. Enabling software data protection requires the three-byte AAh/55h/A0h sequence first; thereafter, every subsequent program attempt must begin with that same sequence. Attempting to program without it causes the device to enter a polling state for tWC duration but writes no data - a safeguard against accidental firmware corruption.
AT29C040A-90PC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-DIP (0.600", 15.24mm)
- 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:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 32-PDIP
AT29C040A-90PC FAQ
1.How can I place an order for AT29C040A-90PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C040A-90PC 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-90PC reliable?
The price and inventory of AT29C040A-90PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C040A-90PC is usually 5 days.
3.What payment methods are accepted for AT29C040A-90PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C040A-90PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C040A-90PC?
AT29C040A-90PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C040A-90PC 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-90PC?
For technical support, including AT29C040A-90PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C040A-90PC requirements.
6.How does Aetrix verify that AT29C040A-90PC is sourced from the original manufacturer or authorized distributors?
All AT29C040A-90PC 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-90PC meets industry standards.
7.What is the process for return or replacement of AT29C040A-90PC?
All AT29C040A-90PC units undergo pre-shipment inspection (PSI). If there is an issue with AT29C040A-90PC, 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-90PC part is unused and in its original packaging.
Return procedure for AT29C040A-90PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT29C040A-90PC Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
Microchip Technology
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AT24C02C-SSHM-T
Microchip Technology
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24LC01BT-I/OT
Microchip Technology
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M24C02-FMC6TG
STMicroelectronics
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AT24CS02-SSHM-T
Microchip Technology
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93LC46BT-I/OT
Microchip Technology
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AT24C04C-SSHM-T
Microchip Technology
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24LC01BT-I/SN
Microchip Technology
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24AA02UIDT-I/OT
Microchip Technology
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AT24C08C-STUM-T
Microchip Technology
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