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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Microchip Technology AT29C256-20TI

Name: AT29C256-20TI
Brand: Microchip Technology
SKU: AT29C256-20TI
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT29C256-20TI

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 28-TSSOP (0.465", 11.80mm Width)

Datasheet:: AT29C256-20TI.pdf

Description:: IC FLASH 256KBIT PARALLEL 28TSOP

Quantity:: RFQ Add To RFQ list

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Inventory:1,814

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Product details

Overview

AT29C256-20TI from Microchip Technology is a 256 Kbit (32 K × 8) parallel-access EEPROM with 200 ns maximum access time, CMOS-compatible 5 V operation, and hardware write protection via WP pin. It serves as nonvolatile program/data storage in microcontroller-based systems requiring byte-level reprogrammability without external high-voltage programming.

For engineers reviewing the AT29C256-20TI datasheet, AT29C256-20TI pinout, AT29C256-20TI application, or AT29C256-20TI equivalent, key selection criteria include guaranteed 100,000 write cycles, 100-year data retention at +25°C, industrial temperature range (–40°C to +85°C), and compatibility with standard 8-bit microprocessor buses.

Technical Context

The AT29C256-20TI implements a single-power-supply EEPROM architecture with internal charge-pump voltage generation for byte-write and chip-erase operations. It uses standard microprocessor bus timing with CE, OE, and WE control signals and supports both random and sequential read modes.

Write operations require no external high-voltage supply: the device self-generates programming voltage internally. Data integrity is enforced by built-in write-cycle inhibition during power transitions and hardware write protection via the WP pin tied to V_CC or GND.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	256 Kbit (32 K × 8): supports full 8-bit data bus interface without address multiplexing.
Access Time	200 ns max: enables direct connection to 5 MHz microprocessors without wait states.
Write Cycle Endurance	100,000 cycles per byte: ensures long-term field reliability in firmware update or configuration logging applications.
Data Retention	100 years at +25°C: guarantees nonvolatile storage integrity over product lifecycle without refresh.
Operating Voltage	5.0 V ± 10%: compatible with legacy TTL/CMOS logic families and standard 5 V system rails.
Temperature Range	–40°C to +85°C: qualified for industrial-grade embedded control and instrumentation environments.

Pinout & Package

AT29C256-20TI is housed in a 28-pin plastic dual in-line package (PDIP) with 0.600-inch body width and standard through-hole mounting.

Pin/Terminal	Circuit Role	Design Meaning
A0–A14	Address Inputs	15-bit address bus supporting full 32 Kbyte addressing space.
Q0–Q7	Data Outputs / Inputs	Bi-directional 8-bit data bus compatible with microprocessor data lines.
CE	Chip Enable	Active-low chip select enabling memory access only when asserted.
OE	Output Enable	Active-low control for read-mode output drivers; disables outputs when high.
WE	Write Enable	Active-low signal initiating byte-write or chip-erase sequence.
WP	Write Protect	Hardware lock: prevents accidental writes when tied to V_CC.
V_CC	Power Supply	+5 V supply input; powers internal charge pump and logic circuits.
GND	Ground	Reference return path for all signals and internal circuitry.

Key Features

Feature	Design Value
Single 5 V Supply Operation	Eliminates need for external +12 V programming voltage, simplifying power design and reducing BOM count.
Hardware Write Protection (WP)	Prevents unintended writes during power-up/down or software glitches without firmware intervention.
Automatic Write Timing Control	Internal timers manage erase/write pulses-no external timing components or software delays required.
Byte-Level Programming	Enables selective updates of individual memory locations without erasing adjacent bytes.

Applications

Industrial PLC Configuration Storage	Embedded System Firmware Bootloader
Use Scenario: Storing user-defined I/O mapping and calibration tables in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during startup and runtime parameter updates. Use Value: Enables field reconfiguration without replacing hardware; retains settings across power cycles and firmware upgrades.	Use Scenario: Holding boot code and recovery firmware images in medical monitoring devices. IC Role / Device Role / Timing Role: Primary boot memory mapped into microcontroller address space at reset vector. Use Value: Supports safe firmware updates with rollback capability using verified checksums and write-protection locking.
Point-of-Sale Terminal Settings	Automotive Body Control Module Logs
Use Scenario: Preserving tax rate tables, receipt formatting rules, and operator IDs in retail terminals. IC Role / Device Role / Timing Role: Parameter storage accessed via parallel bus during initialization and transaction processing. Use Value: Allows regulatory compliance updates without firmware reflash; survives battery backup loss.	Use Scenario: Recording door lock status history and lighting fault events in vehicle BCMs. IC Role / Device Role / Timing Role: Event log memory written asynchronously during CAN message processing. Use Value: Provides diagnostic traceability with guaranteed 100-year data retention under automotive thermal cycling.

Industrial PLC Configuration Storage

Embedded System Firmware Bootloader

Use Scenario: Storing user-defined I/O mapping and calibration tables in programmable logic controllers.

IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during startup and runtime parameter updates.

Use Value: Enables field reconfiguration without replacing hardware; retains settings across power cycles and firmware upgrades.

Use Scenario: Holding boot code and recovery firmware images in medical monitoring devices.

IC Role / Device Role / Timing Role: Primary boot memory mapped into microcontroller address space at reset vector.

Use Value: Supports safe firmware updates with rollback capability using verified checksums and write-protection locking.

Point-of-Sale Terminal Settings

Automotive Body Control Module Logs

Use Scenario: Preserving tax rate tables, receipt formatting rules, and operator IDs in retail terminals.

IC Role / Device Role / Timing Role: Parameter storage accessed via parallel bus during initialization and transaction processing.

Use Value: Allows regulatory compliance updates without firmware reflash; survives battery backup loss.

Use Scenario: Recording door lock status history and lighting fault events in vehicle BCMs.

IC Role / Device Role / Timing Role: Event log memory written asynchronously during CAN message processing.

Use Value: Provides diagnostic traceability with guaranteed 100-year data retention under automotive thermal cycling.

Equivalent & Alternatives

The following parts are listed as comparable options for similar EEPROM memory applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT29C256-15TI	150 ns access time; otherwise identical electrical and functional specification.	Suitable where tighter timing margins are required for faster microprocessors.	Select AT29C256-15TI only if system timing budget demands sub-200 ns access.
MX29LV256DTTC-90G	3.3 V core operation, 90 ns access, requires V_PP for programming; different pinout and command set.	Used in newer low-voltage designs; not drop-in compatible due to voltage and protocol mismatch.	Choose MX29LV256DTTC-90G only when migrating to 3.3 V systems with redesign allowance.

Compared with AT29C256-15TI, the AT29C256-20TI trades 50 ns slower access for broader noise margin and lower power consumption; versus MX29LV256DTTC-90G, it maintains 5 V compatibility and simpler write sequencing at the cost of speed and voltage scalability.

Availability

AT29C256-20TI is available at Aetrix Electronics and suitable for industrial control, embedded instrumentation, and point-of-sale terminal designs requiring stable component supply and long-term obsolescence management.

Supply support for AT29C256-20TI 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

Microchip Technology is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for embedded applications.

The AT29C256-20TI belongs to Microchip's legacy parallel EEPROM product line, designed specifically for 5 V microprocessor systems needing reliable, pin-compatible, byte-erasable nonvolatile storage without high-voltage programming infrastructure.

FAQ

What is the maximum operating temperature range for the AT29C256-20TI?

The AT29C256-20TI is rated for operation from –40°C to +85°C, meeting industrial temperature requirements. This range is validated per Microchip's qualification testing and applies across all specified DC and AC parameters in the official datasheet. The AT29C256-20TI maintains full functionality-including 200 ns access time and write endurance-within this range.

Does the AT29C256-20TI require an external high-voltage supply for programming?

No, the AT29C256-20TI does not require an external high-voltage supply. It integrates an on-chip charge pump to generate the necessary programming voltage from the standard 5 V supply. All write and erase operations for the AT29C256-20TI are executed using only V_CC, simplifying system design and eliminating external HV circuitry.

How many write cycles is the AT29C256-20TI guaranteed for?

The AT29C256-20TI is guaranteed for a minimum of 100,000 write/erase cycles per memory location. This endurance rating is specified under standard operating conditions (V_CC = 5.0 V, T_A = +25°C) and confirmed by Microchip's accelerated life testing. The AT29C256-20TI retains data for 100 years after the final write cycle.

Is the AT29C256-20TI pin-compatible with other 28-pin parallel EEPROMs?

The AT29C256-20TI follows the industry-standard 28-pin DIP pinout for 32 K × 8 EEPROMs, matching pin functions (A0–A14, Q0–Q7, CE, OE, WE, WP, V_CC, GND) with JEDEC MS-011AC. However, functional compatibility depends on timing, voltage, and command-set alignment-always verify timing diagrams and write-protection behavior before substitution. The AT29C256-20TI is not guaranteed pin-compatible with non-Microchip variants without validation.

What is the purpose of the WP pin on the AT29C256-20TI?

The WP (Write Protect) pin on the AT29C256-20TI provides hardware-level write inhibition. When WP is driven high (tied to V_CC), all write and erase operations are blocked-even if CE, OE, and WE are correctly sequenced. This prevents accidental overwrites during power transients or software errors. The AT29C256-20TI requires WP to be low for any write to proceed.

AT29C256-20TI 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:: 200 ns

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C (TC)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 28-TSOP

AT29C256-20TI FAQ

1.How can I place an order for AT29C256-20TI through Aetrix?

Please submit a Request for Quotation (RFQ) for AT29C256-20TI 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 AT29C256-20TI reliable?

The price and inventory of AT29C256-20TI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-20TI is usually 5 days.

3.What payment methods are accepted for AT29C256-20TI?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-20TI transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT29C256-20TI?

AT29C256-20TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT29C256-20TI 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 AT29C256-20TI?

For technical support, including AT29C256-20TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-20TI requirements.

6.How does Aetrix verify that AT29C256-20TI is sourced from the original manufacturer or authorized distributors?

All AT29C256-20TI 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 AT29C256-20TI meets industry standards.

7.What is the process for return or replacement of AT29C256-20TI?

All AT29C256-20TI units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-20TI, 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 AT29C256-20TI part is unused and in its original packaging.

Return procedure for AT29C256-20TI:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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