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Microchip Technology AT29LV256-20JC
- Part No.:
- AT29LV256-20JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT29LV256-20JC.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,863
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Product details
Overview
AT29LV256-20JC from Atmel is a 3.3V-only, 256 Kbit (32K × 8) in-system Flash memory IC with sector-based reprogrammability, 200 ns maximum read access time, 15 mA active current, and 40 µA CMOS standby current. It supports software-controlled sector erase/program, DATA polling, and toggle-bit status detection for embedded firmware storage in industrial controllers and legacy BIOS modules.
For engineers reviewing the AT29LV256-20JC datasheet, AT29LV256-20JC pinout, AT29LV256-20JC application, or AT29LV256-20JC equivalent, this page delivers verified timing parameters, PLCC-32 package mapping, sector-program architecture details, and real-world compatibility guidance for drop-in replacement evaluation and long-life design continuity.
Technical Context
The AT29LV256-20JC implements a 512-sector Flash architecture (64 bytes/sector), with internal latching of full-sector data before automatic erase-and-program execution. Its software data protection requires a three-byte command sequence (AAh/55h/A0h) to enable programming, preventing accidental writes during power transitions or noise events.
It operates exclusively at 3.3V ±0.3V, with TTL/CMOS-compatible I/Os, VCC sense circuitry inhibiting program cycles below 1.8V, and hardware noise filtering rejecting sub-15 ns pulses on WE/CE. Read operation mirrors EPROM behavior: CE and OE low, WE high - enabling direct substitution in legacy 27C256 sockets with voltage adaptation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 × 8), directly replacing 27C256 in 3.3V systems without level-shifting |
| Read Access Time | 200 ns max - meets timing for 5 MHz bus operation with margin |
| Supply Voltage | 3.3V ±0.3V only - eliminates need for 5V rail or charge pumps |
| Active Current | 15 mA at 5 MHz - enables low-power firmware update in battery-backed systems |
| Standby Current | 40 µA (CMOS) - supports ultra-low-power sleep modes in industrial sensors |
| Sector Size | 64 bytes - allows fine-grained firmware patching without full-chip erase |
| Endurance | >10,000 write/erase cycles per sector - supports field-upgradable control logic |
Pinout & Package
AT29LV256-20JC is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32), JEDEC MS-016AE compliant, with 1.44 mm body height and 0.59 mm lead pitch. Pin 1 marked by index notch; leads bent downward at 45° for surface-mount soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 define sector address during programming |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; I/O7 used for DATA polling, I/O6 for toggle-bit status monitoring |
| CE | Chip Enable | Active-low chip select; must be stable before address setup; inhibits programming when high |
| OE | Output Enable | Active-low output control; high-Z state prevents bus contention during read/write transitions |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data during byte load; controls sector programming timing |
| VCC | Power Supply | 3.3V ±0.3V supply; internal VCC sense disables programming if voltage drops below 1.8V |
| GND | Ground Reference | Signal and power ground reference; decoupling capacitor required within 10 mm of VCC pin |
| NC | No Connect | Pin 13 (PLCC top view) - must remain unconnected; no internal bonding |
Key Features
| Feature | Design Value |
|---|---|
| Software Data Protection | Three-byte unlock sequence (5555h/2AAAh/5555h) required before any sector program - prevents inadvertent writes during reset or EMI |
| Sector Program Architecture | 512 independent 64-byte sectors; each sector erased and programmed atomically - enables modular firmware updates without system downtime |
| Status Detection | Dual methods: DATA polling on I/O7 (complement → true data) and toggle-bit on I/O6 - eliminates need for external timers or busy-wait loops |
| Voltage-Tolerant Inputs | Address and control inputs accept 0–5.5V while operating at 3.3V - simplifies interfacing with 5V microcontrollers without level shifters |
| Hardware Write Inhibit | VCC sense, 10 ms power-on delay, and noise filtering (<15 ns pulse rejection) - ensures robustness in electrically noisy industrial environments |
Applications
| Industrial PLC Firmware Storage | Legacy BIOS/UEFI Module |
|---|---|
|
Use Scenario: Storing configuration logic and safety-critical firmware in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile code storage with in-system reprogrammability; 200 ns read access supports real-time scan cycle execution. Use Value: Sector-level updates allow field patches without full system shutdown; 40 µA standby current extends battery backup runtime during power loss. |
Use Scenario: Holding boot firmware and hardware initialization routines in embedded motherboards where space and voltage constraints limit upgrade options. IC Role / Device Role / Timing Role: Drop-in replacement for 27C256 EPROMs in 3.3V designs; software unlock enables secure flash updates via BIOS utility. Use Value: Eliminates UV eraser dependency and socket wear; 10,000-cycle endurance supports multiple BIOS revisions over product lifetime. |
| Medical Device Calibration Data | Telecom Line Card Configuration |
|
Use Scenario: Retaining calibrated sensor offsets and diagnostic thresholds in portable diagnostic equipment requiring regulatory traceability. IC Role / Device Role / Timing Role: Secure, tamper-resistant nonvolatile storage; software protection prevents unauthorized calibration changes. Use Value: Sector locking isolates calibration data from application code; DATA polling ensures deterministic update completion for audit logging. |
Use Scenario: Storing protocol stacks and line-specific configuration parameters in carrier-grade DSLAM and ONU line cards. IC Role / Device Role / Timing Role: Field-upgradable firmware storage with hot-swap compatibility; 3.3V-only operation reduces thermal load on dense PCBs. Use Value: Fast 20 ms sector program time enables rapid service provisioning; PLCC-32 package supports automated optical inspection and rework. |
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 access, 3.3V operation, 100,000 endurance cycles | Higher capacity and faster speed but larger footprint (48-pin TSOP); not pin-compatible | Select when upgrading firmware size headroom is needed and board layout permits larger package |
| MX29LV256DTTC-90G | 256 Kbit, 90 ns access, 3.3V, 100,000 cycles, supports CFI query mode | Superior speed and endurance; CFI support enables auto-detection in bootloader - requires minor firmware adaptation | Choose for new designs needing guaranteed long-term supply and enhanced reliability metrics |
Compared with SST39VF200A-70-4C-NHE and MX29LV256DTTC-90G, the AT29LV256-20JC offers proven legacy compatibility in PLCC-32 form factor and minimal firmware integration effort, making it optimal for sustaining engineering and cost-sensitive industrial replacements.
Availability
AT29LV256-20JC is available at Aetrix Electronics and suitable for industrial PLCs, legacy BIOS modules, medical calibration storage, and telecom line card configurations requiring stable component supply across extended product lifecycles.
Supply support for AT29LV256-20JC 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 fabless semiconductor company specializing in microcontrollers, Flash memory, and secure authentication ICs for industrial, automotive, and consumer applications.
The AT29LV256-20JC belongs to Atmel's LV-series Flash memory product line, designed specifically for 3.3V in-system programmability in space-constrained, long-lifecycle embedded systems where EPROM replacement and field firmware updates are critical.
FAQ
What is the operating temperature range for the AT29LV256-20JC?
The AT29LV256-20JC is rated for commercial temperature operation from 0°C to +70°C. Its PLCC-32 package and internal VCC sense circuitry ensure reliable performance across this range without derating. This makes the AT29LV256-20JC suitable for office equipment, test instrumentation, and non-harsh-environment embedded systems where industrial-grade (-40°C to +85°C) variants like AT29LV256-20JI are not required.
Does the AT29LV256-20JC require high-voltage programming signals?
No, the AT29LV256-20JC performs all programming operations using only its 3.3V supply - no external 12V or 5V programming voltage is needed. Programming is enabled solely through the three-byte software unlock sequence (AAh/55h/A0h) applied to specific addresses. This eliminates high-voltage circuitry and simplifies system design, a key advantage of the AT29LV256-20JC over older EPROM or EEPROM solutions.
How does the AT29LV256-20JC handle sector erase and program operations?
The AT29LV256-20JC executes sector erase and program automatically as a single atomic operation after the 64-byte sector data is fully loaded. No separate erase command is issued - the device internally erases the target sector before programming. The AT29LV256-20JC uses an internal timer and control logic to manage this process, completing it in ≤20 ms per sector, with status detectable via I/O7 DATA polling or I/O6 toggle-bit.
Can the AT29LV256-20JC be used as a direct replacement for the 27C256 EPROM?
Yes, the AT29LV256-20JC is functionally and pinout-compatible with the 27C256 EPROM in PLCC-32 packaging, but requires 3.3V operation instead of 5V. Its read timing (200 ns) matches 27C256-20 speed grades, and control signal behavior (CE/OE/WE) is identical. However, the AT29LV256-20JC adds software write protection and sector programming - features that must be initialized in firmware to avoid accidental writes.
What is the significance of the "-20" in AT29LV256-20JC?
The "-20" in AT29LV256-20JC denotes a maximum read access time of 200 ns, defining its speed grade. This parameter appears in the ordering code to distinguish it from faster (-15, 150 ns) and slower (-25, 250 ns) variants. All versions share identical architecture, pinout, and programming behavior - only AC timing specifications differ. The AT29LV256-20JC thus balances performance and cost for mid-speed embedded applications.
AT29LV256-20JC 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:
- 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:
- 32-PLCC (13.97x11.43)
AT29LV256-20JC FAQ
1.How can I place an order for AT29LV256-20JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29LV256-20JC 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 AT29LV256-20JC reliable?
The price and inventory of AT29LV256-20JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29LV256-20JC is usually 5 days.
3.What payment methods are accepted for AT29LV256-20JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29LV256-20JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29LV256-20JC?
AT29LV256-20JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29LV256-20JC 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 AT29LV256-20JC?
For technical support, including AT29LV256-20JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29LV256-20JC requirements.
6.How does Aetrix verify that AT29LV256-20JC is sourced from the original manufacturer or authorized distributors?
All AT29LV256-20JC 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 AT29LV256-20JC meets industry standards.
7.What is the process for return or replacement of AT29LV256-20JC?
All AT29LV256-20JC units undergo pre-shipment inspection (PSI). If there is an issue with AT29LV256-20JC, 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 AT29LV256-20JC part is unused and in its original packaging.
Return procedure for AT29LV256-20JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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