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Microchip Technology AT29C256-15PC
- Part No.:
- AT29C256-15PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT29C256-15PC.pdf
- Description:
- IC FLASH 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,466
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Product details
Overview
AT29C256-15PC from Atmel is a 256 Kbit (32K × 8) 5V-only Flash memory IC used for nonvolatile program/data storage in embedded systems, supporting in-system reprogramming without high-voltage programming. It delivers 150 ns read access time, 50 mA active current, 300 µA CMOS standby current, and >10,000 write/erase endurance cycles. It operates across commercial temperature range (0°C to 70°C) in a 28-pin PDIP package.
For engineers reviewing the AT29C256-15PC datasheet, AT29C256-15PC pinout, AT29C256-15PC application, or AT29C256-15PC equivalent, key selection criteria include 5V-only operation, page-program architecture (64-byte pages), hardware/software data protection, DATA polling and TOGGLE BIT status detection, and compatibility with standard SRAM bus interfaces.
Technical Context
The AT29C256-15PC implements a page-based Flash architecture where reprogramming occurs in 64-byte blocks using internal address and data latches. Its dual-line chip enable (CE) and output enable (OE) control enables flexible bus interfacing while preventing contention during read operations.
It integrates both hardware-level protection (VCC sense, noise filtering, CE/OE/WE inhibit logic) and software-controlled data protection via three-byte command sequences (e.g., 0xAA→0x55→0xA0). Program cycle completion is verified via I/O7 DATA polling or I/O6 toggle-bit monitoring - both accessible without external timing components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32,768 words × 8 bits) - supports firmware storage or configuration tables in microcontroller-based systems. |
| Read Access Time | 150 ns - compatible with 6–7 MHz system buses without wait states. |
| Page Program Time | 10 ms per 64-byte page - enables efficient field updates without full-chip erase overhead. |
| VCC Supply | 5 V ± 10% - eliminates need for dedicated programming voltage rails. |
| Endurance | >10,000 write/erase cycles - suitable for applications requiring infrequent but reliable field updates. |
| Standby Current | 300 µA (CMOS) - enables low-power retention in battery-backed or energy-sensitive designs. |
| Operating Temperature | 0°C to 70°C - validated for commercial-grade industrial control and instrumentation environments. |
Pinout & Package
AT29C256-15PC is packaged in a 28-pin Plastic Dual Inline Package (PDIP), 0.600" wide (28P6), with pin 1 located at bottom-left corner when notch faces up. Pin 1 is A14; pins 10 and 20 are GND and VCC respectively.
| 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. |
| CE | Chip Enable | Active-low chip select; must be low for read or program operations; high disables outputs and reduces power consumption. |
| OE | Output Enable | Active-low output control; used with CE to gate data bus access and prevent contention during shared-bus operation. |
| WE | Write Enable | Active-low signal initiating byte load or page programming; timing-critical for 150 µs inter-byte loading window. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit data path for reading stored values or loading new data; supports DATA polling on I/O7 and TOGGLE BIT on I/O6. |
| GND | Ground Reference | Pin 10 - primary signal and power return path; requires low-impedance connection for stable read/write margins. |
| VCC | Power Supply | Pin 20 - supplies 5V ±10%; internal VCC sense circuitry inhibits programming if voltage drops below ~3.8 V. |
| NC | No Connect | No internal connection; left unconnected per design - not used for timing, control, or voltage reference. |
Key Features
| Feature | Design Value |
|---|---|
| 5V-only reprogramming | Eliminates requirement for +12 V programming supply - simplifies power architecture and PCB layout. |
| Page-program architecture | Reduces update latency by enabling 64-byte writes without erasing entire chip - critical for patching firmware or logging data. |
| Hardware data protection | VCC sensing, noise filtering, and CE/OE/WE inhibit logic prevent spurious writes during power-up/down or EMI events. |
| Software data protection | User-configurable lock via 3-byte command sequence (0xAA/0x55/0xA0) - prevents accidental overwrites in deployed systems. |
| Status detection (DATA polling / TOGGLE BIT) | Enables host MCU to poll I/O7 or I/O6 instead of using fixed delays - improves system responsiveness and removes timing dependency on worst-case tWC. |
Applications
| Industrial PLC Firmware Storage | Medical Device Configuration Memory |
|---|---|
Use Scenario: Storing firmware images and calibration parameters in programmable logic controllers subject to periodic field updates. IC Role / Device Role / Timing Role: Nonvolatile code storage with in-system reprogrammability; replaces EPROMs requiring UV erasure or socketed replacement. Use Value: Enables remote firmware patches via serial interface without hardware intervention, leveraging 64-byte page writes and software protection to prevent corruption during partial updates. | Use Scenario: Retaining device-specific calibration coefficients and user preferences in portable diagnostic equipment with battery backup. IC Role / Device Role / Timing Role: Low-power configuration memory; operates in CMOS standby mode (<300 µA) during idle periods between measurements. Use Value: Ensures parameter persistence across power cycles while meeting medical-grade reliability requirements via >10,000 endurance cycles and hardware write-inhibit during brownout. |
| Automotive Body Control Module Log Buffer | Legacy Industrial HMI Display Controller |
Use Scenario: Capturing fault codes and operational logs in body control units where EEPROM wear-out limits data retention. IC Role / Device Role / Timing Role: High-endurance data logger; uses page-program mode to append entries without full-sector erase overhead. Use Value: Extends service life beyond EEPROM alternatives by distributing write stress across 32K addresses, supported by DATA polling for deterministic write completion signaling. | Use Scenario: Hosting display fonts, UI bitmaps, and menu logic in older human-machine interface panels with parallel microprocessor buses. IC Role / Device Role / Timing Role: SRAM-compatible read memory; matches 150 ns tACC/tCE timing to legacy 8-bit MPU timing budgets. Use Value: Provides drop-in Flash replacement for obsolete NMOS EPROMs while maintaining identical pinout, voltage levels, and bus protocol behavior. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT29C256-15JC | Same core die and timing specs, but in 32-lead PLCC (32J) package - larger footprint, surface-mount compatible. | Preferred for space-constrained PCBs requiring SMT assembly; unsuitable for through-hole DIP sockets. | Select when board layout mandates surface-mount packaging and thermal/mechanical stability outweighs cost premium. |
| AT29C256-15TI | Identical electrical specs and pinout, but rated for industrial temperature range (−40°C to +85°C) and supplied in TSOP (28T) package. | Suitable for extended-temperature environments such as factory automation or outdoor enclosures where commercial-grade operation is insufficient. | Choose when ambient operating conditions exceed 70°C or require enhanced thermal cycling reliability. |
Compared with AT29C256-15PC, the AT29C256-15JC offers SMT compatibility at the cost of increased board area, while the AT29C256-15TI extends operational range to −40°C/+85°C in a thinner profile - neither is pin-compatible with the PDIP variant, requiring layout revision for substitution.
Availability
AT29C256-15PC is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, and legacy HMI designs requiring stable component supply and long-term obsolescence management.
Supply support for AT29C256-15PC 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.
The AT29C256 product line was designed for embedded systems requiring field-upgradable nonvolatile storage with simple 5V-only programming - targeting cost-sensitive, space-constrained applications where EEPROM endurance or EPROM reprogramming limitations were problematic.
FAQ
What is the maximum clock frequency supported by AT29C256-15PC during read operations?
The AT29C256-15PC does not use a clock input; it is an asynchronous memory device. Its 150 ns read access time (tACC) supports reliable operation with microprocessors or FPGAs running up to approximately 6.7 MHz (1 / 150 ns) without wait states. Timing compliance depends on proper setup/hold margins for CE, OE, and address signals - not a synchronous clock domain.
Does AT29C256-15PC require external high-voltage circuitry for programming?
No, AT29C256-15PC does not require external high-voltage circuitry. It supports 5V-only reprogramming using standard logic-level WE, CE, and OE signals. Internal charge pumps generate necessary programming voltages, and hardware protection (e.g., VCC sense) ensures programming is inhibited below ~3.8 V - eliminating need for +12 V supplies or dedicated programmers.
How is write completion detected on AT29C256-15PC without using a timer?
AT29C256-15PC supports two hardware-assisted status detection methods: DATA polling on I/O7 (complement of loaded data until completion) and TOGGLE BIT on I/O6 (repeated toggling during operation). Both allow the host processor to poll asynchronously - no fixed delay or external timer is required. This ensures deterministic timing across voltage/temperature variations.
Can AT29C256-15PC be used as a direct replacement for standard SRAM in existing designs?
AT29C256-15PC is pin- and function-compatible with many 28-pin SRAMs (e.g., 32K×8 devices) for read operations only. However, write cycles differ fundamentally: it requires page-based programming with specific command sequences and status polling. Direct SRAM replacement is not possible without modifying firmware to handle Flash-specific timing, protection, and erase-before-write logic.
What package type is used for AT29C256-15PC, and are there lead-free options available?
AT29C256-15PC uses a 28-lead Plastic Dual Inline Package (PDIP), 0.600" wide (28P6). Per the original Atmel documentation, this variant was manufactured with leaded solder finish. Lead-free versions (e.g., AT29C256-15PC-XXLF) were not offered in the PDIP configuration - alternative packages like TSOP (28T) or PLCC (32J) may have RoHS-compliant variants, but AT29C256-15PC itself is not lead-free certified.
AT29C256-15PC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-DIP (0.600", 15.24mm)
- 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:
- 10ms
- Access Time:
- 150 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-PDIP
AT29C256-15PC FAQ
1.How can I place an order for AT29C256-15PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT29C256-15PC 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 AT29C256-15PC reliable?
The price and inventory of AT29C256-15PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT29C256-15PC is usually 5 days.
3.What payment methods are accepted for AT29C256-15PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT29C256-15PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT29C256-15PC?
AT29C256-15PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT29C256-15PC 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 AT29C256-15PC?
For technical support, including AT29C256-15PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT29C256-15PC requirements.
6.How does Aetrix verify that AT29C256-15PC is sourced from the original manufacturer or authorized distributors?
All AT29C256-15PC 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 AT29C256-15PC meets industry standards.
7.What is the process for return or replacement of AT29C256-15PC?
All AT29C256-15PC units undergo pre-shipment inspection (PSI). If there is an issue with AT29C256-15PC, 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 AT29C256-15PC part is unused and in its original packaging.
Return procedure for AT29C256-15PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT29C256-15PC Tags
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