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Microchip Technology AT29C040A-90TC
- Part No.:
- AT29C040A-90TC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-TFSOP (0.724", 18.40mm Width)
- Datasheet:
-
AT29C040A-90TC.pdf
- Description:
- IC FLASH 4MBIT PARALLEL 32TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,002
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Product details
Overview
AT29C040A-90TC from Atmel is a 4-Mbit (512K × 8) 5-volt-only Flash memory IC used for in-system firmware storage and boot code retention in embedded controllers. It delivers 90 ns read access time, supports 256-byte sector programming with internal latches, features dual 16K-byte boot blocks with independent lockout, and operates across commercial temperature range (0°C to 70°C) in a 32-lead TSOP package.
For engineers reviewing the AT29C040A-90TC datasheet, AT29C040A-90TC pinout, AT29C040A-90TC application, or AT29C040A-90TC equivalent, this page provides verified technical context, real-world use cases, pin-level design meaning, hardware/software data protection implementation details, and validated alternative options for legacy system maintenance and industrial controller upgrades.
Technical Context
The AT29C040A-90TC implements a sector-based Flash architecture with 2048 × 256-byte sectors, enabling byte-load-and-program operations without high-voltage programming circuitry. Its dual-line chip enable (CE) and output enable (OE) control allows bus contention avoidance during mixed-read/write system operation.
It integrates both hardware-level VCC sensing (program inhibit below 3.8 V) and software-controlled data protection via three-byte unlock sequences (AAh/55h/A0h), plus boot block lockout activation using a seven-command algorithm. End-of-program detection is supported by DATA polling on I/O7 and TOGGLE bit behavior on I/O6.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 4 Mbit (512K × 8), sufficient for full BIOS/firmware images in legacy x86 and microcontroller-based systems |
| Read Access Time | 90 ns - enables direct execution from Flash (XIP) in timing-critical boot stages |
| Sector Size | 256 bytes - matches common EEPROM update granularity and simplifies field firmware patching |
| Program Cycle Time | 10 ms per sector - deterministic erase+program latency for predictable system update windows |
| Supply Voltage | 5 V ± 10% - compatible with legacy 5V logic buses and eliminates need for auxiliary voltage rails |
| Endurance | >10,000 write/erase cycles - supports frequent field updates in industrial HMI and PLC firmware |
| Standby Current | 100 µA CMOS - enables low-power retention in battery-backed or energy-constrained applications |
Pinout & Package
AT29C040A-90TC uses a 32-lead Thin Small Outline Package (TSOP Type 1), 8 mm × 20 mm body, JEDEC MO-142 compliant, with gull-wing leads and pin 1 identifier 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 during programming |
| I/O0–I/O7 | Bidirectional Data Bus | CMOS/TTL-compatible 8-bit data path; I/O7 used for DATA polling, I/O6 for TOGGLE bit status monitoring |
| CE | Chip Enable | Active-low device selection; must be low with OE low for read, high to inhibit all operations including program |
| OE | Output Enable | Active-low output control; high during programming to place outputs in high-Z state and avoid bus conflicts |
| WE | Write Enable | Active-low programming strobe; falling edge latches address/data during byte load; timing-critical (tWP ≥ 90 ns) |
| VCC | Power Supply | +5 V ± 10% main supply; internal VCC sense disables programming if voltage drops below 3.8 V |
| GND | Ground Reference | Signal and power return; decoupling capacitor required near VCC/GND pins for stable sector programming |
| NC | No Connect | Unbonded pin; must remain unconnected per Atmel design - no pull-up/down or routing allowed |
Key Features
| Feature | Design Value |
|---|---|
| Single 5V Reprogramming | Eliminates need for +12V programming supplies - simplifies PCB layout and reduces BOM count in legacy designs |
| Hardware Data Protection | VCC sense + 5 ms power-on delay + noise filtering (<15 ns pulses rejected) prevents spurious writes during brown-out or EMI events |
| Software Data Protection | Three-byte unlock sequence (AAh/55h/A0h) ensures firmware updates require explicit host controller authorization |
| Dual Boot Block Lockout | Independent 16K-byte lockout for lower (0x00000–0x03FFF) and upper (0x7C000–0x7FFFF) regions secures bootloader and recovery code |
| DATA Polling & TOGGLE Bit | Real-time program status feedback via I/O7 complement or I/O6 toggling - avoids fixed-timing delays and improves system responsiveness |
Applications
| Industrial PLC Firmware Storage | Legacy PC BIOS Retention |
|---|---|
Use Scenario: Storing ladder logic programs and configuration parameters in programmable logic controllers requiring field-upgradable nonvolatile memory. IC Role / Device Role / Timing Role: Primary firmware storage device accessed during cold start and runtime parameter reload; 90 ns access supports deterministic scan cycle timing. Use Value: Sector-level erasure enables partial firmware updates without full chip reprogramming, reducing downtime during maintenance. | Use Scenario: Holding BIOS code and hardware initialization routines in desktop motherboards and embedded x86 platforms prior to OS boot. IC Role / Device Role / Timing Role: Boot ROM mapped at 0xF0000–0xFFFFF; CE/OE dual-control prevents bus contention with chipset during POST. Use Value: Dual 16K boot blocks allow separate locking of primary and fallback BIOS images, enhancing system reliability after failed updates. |
| Medical Device Configuration Memory | Telecom Line Card Boot Image |
Use Scenario: Storing calibration tables, safety-critical operational limits, and user-configurable modes in FDA-regulated diagnostic equipment. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed during power-on self-test; software data protection prevents accidental overwrite during service mode. Use Value: >10,000 endurance cycles support repeated recalibration and regulatory audit logging without memory wear-out concerns. | Use Scenario: Hosting boot firmware and FPGA configuration bitstreams on carrier-grade line cards where hot-swap capability requires fast, reliable reinitialization. IC Role / Device Role / Timing Role: System boot memory mapped into processor address space; TSOP package enables high-density board layout in constrained telecom modules. Use Value: 100 µA standby current minimizes quiescent power draw during card standby, meeting NEBS Level 3 thermal requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29LV040B-90EC | 4 Mbit, 90 ns, 3.0–3.6 V supply only; requires 12 V for reset; no boot block lockout | Not suitable for 5V-only systems; lacks hardware/software lockout - higher risk of inadvertent firmware corruption | Select only if migrating to 3.3V platform and external 12V reset source is available |
| MX29LV040CTTI-90G | 4 Mbit, 90 ns, 3.0–3.6 V supply; software command set differs; boot blocks not independently lockable | Requires voltage translation for 5V bus interfaces; no dual-boot-block security model - less suitable for safety-critical boot paths | Prefer for new 3.3V designs where cost is prioritized over legacy compatibility and boot security |
Compared with AM29LV040B-90EC and MX29LV040CTTI-90G, the AT29C040A-90TC uniquely supports true 5V-only operation with dual independent boot block lockout and integrated VCC-sense hardware protection - making it the only option for maintaining functional safety and electrical compatibility in existing 5V industrial control systems.
Availability
AT29C040A-90TC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS retention, medical device configuration memory, and telecom line card boot image applications requiring stable component supply and long-term obsolescence management.
Supply support for AT29C040A-90TC 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 U.S.-based semiconductor company specializing in microcontrollers, Flash memory, and secure authentication devices.
The AT29C040A-90TC belongs to Atmel's 5-volt-only Flash family designed specifically for drop-in replacement of EPROMs and EEPROMs in legacy embedded systems requiring in-system reprogrammability without high-voltage programming infrastructure.
FAQ
What is the operating temperature range for the AT29C040A-90TC?
The AT29C040A-90TC is rated for commercial temperature operation from 0°C to 70°C. This specification is confirmed in the Ordering Information table of the official Atmel datasheet (Rev. 0333I–FLASH–05/02), where the "-90TC" suffix explicitly denotes the commercial-grade TSOP variant. Industrial variants (e.g., AT29C040A-90TI) support –40°C to +85°C but use different suffixes and packaging.
Does the AT29C040A-90TC support true 5V-only programming without external high voltage?
Yes, the AT29C040A-90TC supports full 5V-only reprogramming - no external 12V or 12.5V supply is required. Programming is initiated using standard 5V logic levels and specific three-byte unlock sequences (e.g., AAh/55h/A0h). This capability is documented in the "Features" and "Device Operation" sections of the Atmel datasheet and distinguishes it from earlier Flash devices requiring high-voltage VPP pins.
How does the boot block lockout feature work on the AT29C040A-90TC?
The AT29C040A-90TC contains two independent 16K-byte boot blocks - one at the lowest addresses (0x00000–0x03FFF) and one at the highest (0x7C000–0x7FFFF). Each can be permanently locked against programming using a seven-command software algorithm. Once enabled, the locked block cannot be erased or written, even by chip erase. The lockout state is persistent through power cycles and is verified by reading status bits at 0x00002H (lower block) and 0x7FFF2H (upper block).
Can the AT29C040A-90TC be used as a direct replacement for standard EPROMs like the 27C040?
Yes, the AT29C040A-90TC is pin-compatible and functionally compatible with the 27C040 EPROM in read mode: CE/OE/WE control matches standard EPROM timing, and outputs are TTL/CMOS compatible. However, unlike EPROMs, it supports in-system reprogramming without UV erasure. Careful attention must be paid to WE timing and software unlock sequences during programming - direct substitution is valid only for read operations unless the host system implements proper Flash command protocols.
What package type does the AT29C040A-90TC use, and what are its key mechanical dimensions?
The AT29C040A-90TC uses a 32-lead Thin Small Outline Package (TSOP Type 1), designated "32T" in Atmel's ordering matrix. Its body measures 8 mm × 20 mm (width × length), with 0.50 mm lead pitch, 0.60 mm max height (A dimension), and gull-wing leads conforming to JEDEC MO-142, Variation BD. Pin 1 is marked by a notch in the package top-left corner.
AT29C040A-90TC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-TFSOP (0.724", 18.40mm Width)
- Packaging:
- Tray
- 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:
- Surface Mount
- Supplier Device Package:
- 32-TSOP
AT29C040A-90TC FAQ
1.How can I place an order for AT29C040A-90TC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C040A-90TC 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-90TC reliable?
The price and inventory of AT29C040A-90TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C040A-90TC is usually 5 days.
3.What payment methods are accepted for AT29C040A-90TC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C040A-90TC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C040A-90TC?
AT29C040A-90TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C040A-90TC 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-90TC?
For technical support, including AT29C040A-90TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C040A-90TC requirements.
6.How does Aetrix verify that AT29C040A-90TC is sourced from the original manufacturer or authorized distributors?
All AT29C040A-90TC 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-90TC meets industry standards.
7.What is the process for return or replacement of AT29C040A-90TC?
All AT29C040A-90TC units undergo pre-shipment inspection (PSI). If there is an issue with AT29C040A-90TC, 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-90TC part is unused and in its original packaging.
Return procedure for AT29C040A-90TC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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