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Microchip Technology AT29C256-15TC
- Part No.:
- AT29C256-15TC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT29C256-15TC.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,889
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Product details
Overview
AT29C256-15TC from Atmel is a 5V-only, 256 Kbit (32K × 8) Flash memory IC designed for in-system reprogrammability in embedded controllers and firmware storage applications. It delivers 150 ns read access time, supports page programming of 64-byte blocks in 10 ms, and features hardware and software data protection. Its CMOS/TTL-compatible I/O, 300 µA standby current, and industrial temperature range (-40°C to +85°C) make it suitable for legacy industrial control and boot code storage.
For engineers reviewing the AT29C256-15TC datasheet, AT29C256-15TC pinout, AT29C256-15TC application, or AT29C256-15TC equivalent, key selection criteria include verified 150 ns tACC timing, PLCC/TSOP/PDIP package compatibility, 5V ±10% supply tolerance, DATA polling and toggle-bit program status detection, and software-controlled chip erase via six-byte command sequence.
Technical Context
The AT29C256-15TC implements a nonvolatile Flash architecture with internal address/data latches for 64-byte page loads and an autonomous internal timer for erase-and-program execution. It uses standard parallel bus control (CE/OE/WE) and operates identically to SRAM during reads, enabling drop-in replacement in existing memory interfaces.
Its dual data protection-hardware-based VCC sense (<3.8 V inhibit), noise filtering (<15 ns pulse rejection), and software lock requiring three-command enable/disable sequences-ensures robustness against inadvertent writes during power transitions or EMI events. The device supports both hardware and software product identification (Manufacturer Code 1Fh, Device Code DCh).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 words × 8 bits); sufficient for full boot loader or configuration table storage in 8-bit microcontroller systems. |
| Read Access Time (tACC) | 150 ns max; defines minimum clock cycle for reliable read operations in 6–7 MHz bus environments. |
| Page Program Time | 10 ms typical; enables rapid field updates of 64-byte firmware segments without full-chip erase overhead. |
| VCC Supply Range | 5 V ±10%; eliminates need for precision voltage regulation in cost-sensitive industrial designs. |
| Standby Current (ISB1) | 300 µA max at CMOS standby; reduces quiescent power in battery-backed or low-power sleep modes. |
| Endurance | >10,000 write/erase cycles per sector; supports long-term field firmware upgrades in deployed equipment. |
| Operating Temperature | -40°C to +85°C; qualified for industrial-grade operation in motor drives, PLCs, and instrumentation. |
Pinout & Package
AT29C256-15TC is available in 28-lead Plastic Thin Small Outline Package (TSOP, Type I, 8 mm × 13.4 mm), compliant with JEDEC MO-183. Pin 1 is marked by a beveled corner; pins 1–14 and 15–28 are on opposing long edges. PLCC (32J) and PDIP (28P6) variants exist but are not applicable to this specific -15TC ordering code.
| 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 page 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 during program/erase cycles. |
| CE | Chip Enable | Active-low chip select; must be low for read, program, or erase; high-Z output when high. |
| OE | Output Enable | Active-low output control; enables data output only when CE is also low; prevents bus contention. |
| WE | Write Enable | Active-low control for byte load and page programming; initiates internal latch and timer on falling edge. |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O drivers; internal VCC sense disables programming if below 3.8 V. |
| GND | Ground Reference | Signal and power return path; decoupling capacitor required near VCC pin for stable operation. |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates need for external +12 V programming voltage, simplifying power design and enabling true in-system updates. |
| Page-based programming (64 bytes) | Reduces update latency vs. full-chip erase; allows targeted firmware patching without disrupting unrelated memory regions. |
| DATA polling & toggle-bit status | Enables real-time, non-blocking detection of program/erase completion using only I/O6/I/O7-no external timers or interrupts needed. |
| Hardware + software data protection | Prevents accidental writes during brown-out, reset, or noise events via VCC sensing, noise filtering, and 3-command software lock. |
| CMOS/TTL I/O compatibility | Direct interfacing with legacy 8051, Z80, or 68K-based controllers without level-shifting circuitry. |
Applications
| Industrial PLC Firmware Storage | Embedded Boot Loader Memory |
|---|---|
|
Use Scenario: Storing firmware images and configuration parameters in programmable logic controllers operating in factory-floor environments with wide temperature swings and electrical noise. IC Role / Device Role / Timing Role: Nonvolatile program memory mapped into microcontroller address space; accessed as SRAM-equivalent during boot and runtime. Use Value: 150 ns tACC ensures deterministic timing in 6–7 MHz bus systems; 300 µA standby current extends uptime during maintenance mode; industrial temp rating guarantees reliability at 85°C ambient. |
Use Scenario: Holding primary boot code for 8-bit microcontrollers in medical devices where firmware integrity and field-upgradability are critical. IC Role / Device Role / Timing Role: First-stage boot ROM providing initial instruction fetch and secure jump to application code; accessed during cold start and reset recovery. Use Value: Software data protection prevents corruption during power loss; 10,000-cycle endurance supports lifetime field updates; 5V-only operation avoids extra voltage rails. |
| Legacy Instrumentation Calibration Data | Communications Module Configuration Store |
|
Use Scenario: Retaining calibrated sensor offsets and gain coefficients in handheld test equipment subject to frequent battery changes and thermal cycling. IC Role / Device Role / Timing Role: Parameter EEPROM replacement; written infrequently during calibration, read on every power-up. Use Value: Hardware VCC-sense protection prevents write errors during battery insertion; 300 µA ISB1 minimizes self-discharge impact on backup batteries. |
Use Scenario: Storing protocol stacks, MAC addresses, and network settings in RS-485 or Modbus gateways deployed in distributed automation networks. IC Role / Device Role / Timing Role: Configuration nonvolatile memory accessed over parallel bus during initialization and dynamic parameter reload. Use Value: Page programming enables fast field updates of communication parameters; DATA polling allows host MCU to manage timing without fixed delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT29C256-15JI | Same die, identical timing and features, but in 32-lead PLCC (32J) package instead of TSOP (28T). | Requires PCB layout change due to different footprint, lead count, and mounting height; suited for through-hole or surface-mount PLCC sockets. | Select when mechanical constraints favor PLCC or when legacy board reuse mandates 32-pin footprint. |
| AM29LV256M-150EC | 3.3 V core with 5 V I/O tolerant; 150 ns tACC; 256 Mbit density; supports CFI query and sector protection. | Higher density and lower voltage operation, but requires level translation or mixed-voltage design; not pin-compatible. | Choose for new designs needing higher capacity or lower power, accepting redesign effort for voltage and interface differences. |
Compared with AT29C256-15TC, the AT29C256-15JI offers identical functionality in a different package-ideal for socketed or ruggedized industrial layouts-while the AM29LV256M-150EC provides modern 3.3 V efficiency and CFI compatibility at the cost of full hardware redesign and non-drop-in integration.
Availability
AT29C256-15TC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, embedded boot loader memory, legacy instrumentation calibration data retention, and communications module configuration storage requiring stable component supply across extended production lifecycles.
Supply support for AT29C256-15TC 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, nonvolatile memory, and security ICs, with a legacy of robust industrial-grade Flash products.
The AT29C256 series was designed specifically for 5V embedded systems requiring field-upgradable firmware storage with simple parallel bus interfaces and high immunity to power-related corruption.
FAQ
What is the maximum read access time specified for the AT29C256-15TC?
The AT29C256-15TC has a maximum address-to-output delay (tACC) of 150 ns, as confirmed in the AC Read Characteristics table of the official Atmel datasheet (Rev. 0046O–FLASH–06/02). This value applies across the full industrial temperature range (-40°C to +85°C) and 5 V ±10% supply condition, making it suitable for systems with ≤6.6 MHz bus timing budgets. The "-15" suffix explicitly denotes the 150 ns speed grade.
Does the AT29C256-15TC require high-voltage programming signals?
No, the AT29C256-15TC is a 5-volt-only Flash memory: all programming, erasure, and protection functions operate using standard 5 V logic levels-no external +12 V or +5 VPP voltage is required. Programming is initiated via WE/CE-controlled byte loads and internally timed; hardware protection inhibits writes if VCC drops below ~3.8 V, ensuring safe operation during power transitions.
How is program completion detected on the AT29C256-15TC?
The AT29C256-15TC supports two hardware-supported methods: DATA polling (monitoring complement state of I/O7 during read) and toggle-bit detection (observing toggling of I/O6). Both methods are active during internal program or erase cycles and require no external timing components. Once I/O7 returns true data or I/O6 stops toggling, the cycle is complete-and the AT29C256-15TC is ready for the next access.
What package type does the AT29C256-15TC use?
The AT29C256-15TC uses a 28-lead Plastic Thin Small Outline Package (TSOP, Type I), designated as package code "28T" in Atmel's ordering information. Its dimensions are 8 mm × 13.4 mm, with 0.55 mm lead pitch, and it complies with JEDEC MO-183. This surface-mount package is distinct from the PLCC (32J) and PDIP (28P6) variants offered under other ordering codes.
Can the AT29C256-15TC be used as a direct replacement for standard SRAM in existing designs?
The AT29C256-15TC behaves like an SRAM during read operations-CE/OE/WE control matches standard asynchronous SRAM timing-but it is not a true drop-in SRAM replacement. Writes require page-based programming sequences and status polling. For read-only or infrequent-write applications with compatible timing (150 ns), it can substitute SRAM; however, write cycles demand firmware-level adaptation to handle DATA polling, software protection, and 10 ms page programming latency.
AT29C256-15TC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tray
- 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:
- 10ms
- Access Time:
- 150 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSOP
AT29C256-15TC FAQ
1.How can I place an order for AT29C256-15TC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-15TC 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 AT29C256-15TC reliable?
The price and inventory of AT29C256-15TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-15TC is usually 5 days.
3.What payment methods are accepted for AT29C256-15TC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-15TC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-15TC?
AT29C256-15TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-15TC 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 AT29C256-15TC?
For technical support, including AT29C256-15TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-15TC requirements.
6.How does Aetrix verify that AT29C256-15TC is sourced from the original manufacturer or authorized distributors?
All AT29C256-15TC 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 AT29C256-15TC meets industry standards.
7.What is the process for return or replacement of AT29C256-15TC?
All AT29C256-15TC units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-15TC, 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 AT29C256-15TC part is unused and in its original packaging.
Return procedure for AT29C256-15TC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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