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Microchip Technology AT29LV256-20TC-T
- Part No.:
- AT29LV256-20TC-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT29LV256-20TC-T.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,031
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Product details
Overview
AT29LV256-20TC-T from Atmel is a 3.3V-only, 256 Kbit (32K × 8) Flash memory IC designed for in-system reprogrammability in embedded microcontroller systems. It features 150 ns read access time, sector-based programming with 512 × 64-byte sectors, 15 mA active current, and 40 µA CMOS standby current, enabling low-power firmware updates in industrial controllers and legacy BIOS modules.
For engineers reviewing the AT29LV256-20TC-T datasheet, AT29LV256-20TC-T pinout, AT29LV256-20TC-T application, or AT29LV256-20TC-T equivalent, key selection criteria include 3.3V-only operation, software data protection sequence, DATA polling/Toggle Bit program status detection, sector erase-and-program architecture, and TSOP-28 package compatibility with space-constrained PCB layouts.
Technical Context
The AT29LV256-20TC-T implements a sector-erase Flash architecture with internal latching of 64-byte data blocks and automatic erase-before-program sequencing. Its software data protection requires a three-byte command sequence (AAh→55h→A0h) to enable programming, preventing inadvertent writes during power transitions or noise events.
It supports standard EPROM-like read timing with dual-line chip select (CE) and output enable (OE) control, TTL/CMOS-compatible I/O levels, and hardware safeguards including VCC sense (<1.8V inhibit), 10 ms power-on delay, and 15 ns noise filtering on WE/CE inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8 bits) - supports full firmware image storage for 8-bit microcontrollers |
| Read Access Time | 200 ns max - meets timing requirements for 5 MHz bus interfaces without wait states |
| Supply Voltage | 3.0 V to 3.6 V - operates directly from standard 3.3V LDO rails, no level shifters required |
| Active Current | 15 mA at 5 MHz - enables low-power operation in battery-backed or energy-sensitive systems |
| Standby Current | 40 µA CMOS - reduces quiescent power in always-on embedded monitoring devices |
| Endurance | >10,000 program/erase cycles per sector - supports field firmware updates over product lifetime |
| Operating Temp | -40°C to +85°C - qualified for industrial temperature range applications |
Pinout & Package
AT29LV256-20TC-T is housed in a 28-lead Thin Small Outline Package (TSOP Type 1), measuring 11.7 mm × 7.9 mm × 1.25 mm, with gull-wing leads and JEDEC-standard 0.55 mm pitch. The package is RoHS-compliant and optimized for automated surface-mount assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A0–A5 select byte within 64-byte sector |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface for read/write operations; supports DATA polling on I/O7 and Toggle Bit on I/O6 |
| CE | Chip Enable | Active-low global device select; must be low for read or program; high-Z output when asserted high |
| OE | Output Enable | Active-low output control; used with CE to prevent bus contention during shared-memory access |
| WE | Write Enable | Active-low write strobe; controls byte load timing and initiates sector programming when CE is low |
| VCC | Power Supply | 3.3V ±0.3V supply input; includes internal VCC sense circuitry to inhibit programming below 1.8V |
| GND | Ground Reference | Signal and power ground reference for all I/O and internal logic |
Key Features
| Feature | Design Value |
|---|---|
| Software Data Protection | Three-byte unlock sequence (5555h/2AAAh/5555h) required before each sector program - prevents accidental firmware corruption during debug or brown-out |
| Sector Program Architecture | 512 independent 64-byte sectors - enables granular firmware patching without full-chip erase, reducing update time and wear |
| DATA Polling & Toggle Bit | I/O7 complement-read and I/O6 toggle indicate program completion - eliminates need for fixed delays or external timers in host firmware |
| Hardware Write Inhibit | VCC sense, 10 ms power-on delay, and 15 ns noise filtering on WE/CE - ensures robustness against power supply transients and EMI |
| 3.3V-Only Operation | No 12V or 5V programming voltage required - simplifies system power design and eliminates high-voltage charge pumps |
Applications
| Industrial PLC Firmware Storage | Legacy PC BIOS Memory |
|---|---|
Use Scenario: Storing and updating ladder logic firmware in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile code storage with in-system reprogrammability via RS-485 or CAN-connected host processor. Use Value: Sector-level updates allow incremental firmware patches without full reflash, minimizing machine downtime during maintenance windows. |
Use Scenario: Replacing obsolete 27C256 EPROMs in legacy desktop/server motherboards requiring BIOS upgrades. IC Role / Device Role / Timing Role: Drop-in compatible Flash memory providing identical 28-pin DIP footprint and read timing, but with in-circuit programmability. Use Value: Eliminates need for UV erasers or socketed EPROM programmers - BIOS updates performed directly via motherboard JTAG or LPC interface. |
| Embedded Telematics Bootloader | Point-of-Sale Terminal Configuration |
Use Scenario: Storing secure bootloader code and cryptographic keys in vehicle telematics units subject to over-the-air (OTA) firmware updates. IC Role / Device Role / Timing Role: Trusted boot memory with hardware and software write protection, accessed during cold boot before main application starts. Use Value: Prevents unauthorized modification of boot code via DATA polling verification and VCC-sense lockout during power ramp-up. |
Use Scenario: Holding localized language packs, tax tables, and regulatory compliance settings in retail POS terminals across global deployments. IC Role / Device Role / Timing Role: Field-configurable parameter storage updated via USB or SD card without disassembly or service technician intervention. Use Value: 40 µA standby current enables battery-backed retention during store power outages; sector erase allows region-specific data updates without affecting core application. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SST39VF200A-70-4C-NHE | 2 Mbit density, 70 ns read access, 3.3V-only, 100,000 endurance cycles | Higher capacity and faster access, but larger 48-pin TSOP package | Select when >256 Kbit storage or sub-100 ns timing is required; not pin-compatible |
| MX29LV256DTTI-70G | 256 Kbit, 70 ns read, 3.3V-only, 100,000 endurance, supports CFI query mode | Includes Common Flash Interface for auto-detection in BIOS/bootloader; same 28-pin TSOP-28 footprint | Preferred for new designs requiring standardized flash initialization; pin-compatible with AT29LV256-20TC-T |
Compared with SST39VF200A-70-4C-NHE and MX29LV256DTTI-70G, the AT29LV256-20TC-T offers proven industrial reliability and simpler command set for legacy systems, while MX29LV256DTTI-70G provides CFI compatibility for modern boot firmware, and SST39VF200A delivers higher density where board space permits larger packages.
Availability
AT29LV256-20TC-T is available at Aetrix Electronics and suitable for industrial PLCs, legacy BIOS modules, and embedded telematics systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant TSOP packaging.
Supply support for AT29LV256-20TC-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) is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs for industrial, automotive, and consumer applications.
The AT29LV256 product line was designed as a 3.3V-only Flash memory replacement for 5V EPROMs in legacy embedded systems, emphasizing in-system reprogrammability, low-power operation, and robust write protection for mission-critical firmware storage.
FAQ
What is the maximum read access time specified for the AT29LV256-20TC-T?
The AT29LV256-20TC-T has a maximum read access time of 200 ns, as indicated by the "-20" suffix in its part number. This specification applies across the commercial and industrial temperature ranges when operating at VCC = 3.3V ±0.3V. The value is guaranteed under AC test conditions with CL = 5 pF and f = 5 MHz, and it defines the worst-case delay from address or control signal stabilization to valid data appearing on I/O0–I/O7. This timing enables direct interfacing with 5 MHz microcontroller buses without wait-state insertion.
Does the AT29LV256-20TC-T require high-voltage programming signals?
No, the AT29LV256-20TC-T does not require high-voltage programming signals. It is a 3.3V-only Flash memory: all read, write, and erase operations are performed using standard 3.3V logic levels. Programming is enabled solely through a software command sequence (AAh→55h→A0h) applied to the address and data bus. Internal circuitry handles sector erase and program timing automatically, eliminating the need for external 12V supplies or charge pumps commonly found in older EPROM or EEPROM devices.
How many program/erase cycles is the AT29LV256-20TC-T rated for?
The AT29LV256-20TC-T is rated for typical endurance of more than 10,000 program/erase cycles per sector. This specification reflects the number of times a given 64-byte sector can be erased and reprogrammed before parametric degradation exceeds limits. Endurance is measured under standard conditions (VCC = 3.3V, TA = 25°C) and is not guaranteed for the entire array simultaneously - individual sectors may exceed this count, and wear leveling is not implemented internally, so system-level management is recommended for high-update-rate applications.
What package type does the AT29LV256-20TC-T use, and what are its key mechanical dimensions?
The AT29LV256-20TC-T uses a 28-lead Thin Small Outline Package (TSOP Type 1), designated "28T" in Atmel's ordering nomenclature. Its body dimensions are 11.7 mm × 7.9 mm × 1.25 mm (L × W × H), with 0.55 mm lead pitch and gull-wing terminations. The package complies with JEDEC MO-153 standards and is optimized for high-density surface-mount assembly. Pin 1 is marked by a beveled corner, and the device is RoHS-compliant with lead-free finish.
Can the AT29LV256-20TC-T be used as a direct replacement for the AT29LV256-20JC in a PLCC socket?
No, the AT29LV256-20TC-T cannot be used as a direct replacement for the AT29LV256-20JC because they use incompatible packages: the "-TC-T" variant is in a 28-lead TSOP, while the "-JC" variant is in a 32-lead PLCC. Their pinouts differ significantly - the TSOP has dedicated VCC/GND pins at opposite ends and linear pin numbering, whereas the PLCC uses a square layout with NC and DC pins. Physical mounting, solder reflow profile, and PCB footprint are not interchangeable; a board redesign is required to migrate between these packages.
AT29LV256-20TC-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- FLASH
- Technology:
- FLASH
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K 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:
- 28-TSOP
AT29LV256-20TC-T FAQ
1.How can I place an order for AT29LV256-20TC-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29LV256-20TC-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 AT29LV256-20TC-T reliable?
The price and inventory of AT29LV256-20TC-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29LV256-20TC-T is usually 5 days.
3.What payment methods are accepted for AT29LV256-20TC-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29LV256-20TC-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29LV256-20TC-T?
AT29LV256-20TC-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29LV256-20TC-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 AT29LV256-20TC-T?
For technical support, including AT29LV256-20TC-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29LV256-20TC-T requirements.
6.How does Aetrix verify that AT29LV256-20TC-T is sourced from the original manufacturer or authorized distributors?
All AT29LV256-20TC-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 AT29LV256-20TC-T meets industry standards.
7.What is the process for return or replacement of AT29LV256-20TC-T?
All AT29LV256-20TC-T units undergo pre-shipment inspection (PSI). If there is an issue with AT29LV256-20TC-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 AT29LV256-20TC-T part is unused and in its original packaging.
Return procedure for AT29LV256-20TC-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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