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Microchip Technology AT27C256R-15PC
- Part No.:
- AT27C256R-15PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT27C256R-15PC.pdf
- Description:
- IC EPROM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,453
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Product details
Overview
AT27C256R-15PC from Atmel is a 256K-bit (32K × 8) one-time programmable EPROM with 45 ns read access time, 5V ±10% supply operation, and JEDEC-standard 28-lead PDIP packaging. It delivers fast, low-power nonvolatile storage for firmware in microprocessor systems requiring deterministic timing and no wait states.
For engineers reviewing the AT27C256R-15PC datasheet, AT27C256R-15PC pinout, AT27C256R-15PC application, or AT27C256R-15PC equivalent, key selection criteria include verified 45 ns tACC, CMOS/TTL-compatible I/O, Rapid™ programming at 100 µs/byte, VPP = 12.0 V programming voltage, and industrial-grade temperature range support.
Technical Context
The AT27C256R-15PC implements a two-line control architecture using CE and OE to manage bus contention and output enable timing. Its internal address decoder supports full 15-bit addressing (A0–A14) for 32K-byte access, with NC pins isolated per package variant.
It uses Atmel's scaled CMOS process to achieve 100 µA max standby current and 20 mA max active current at 5 MHz, while maintaining 2,000V ESD protection and 200 mA latchup immunity-critical for embedded system reliability during power transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8), enabling full firmware image storage without external paging logic |
| Read Access Time | 45 ns max (tACC), eliminating WAIT states on 5 MHz+ microprocessors |
| Supply Voltage | 5 V ±10%, compatible with standard TTL/CMOS logic rails without regulation overhead |
| Standby Current | 100 µA max, reducing quiescent power in battery-backed or low-duty-cycle systems |
| Programming Speed | 100 µs/byte typical (Rapid™ algorithm), cutting production programming time vs. legacy EPROMs |
| VPP Programming Voltage | 12.0 V ±0.5 V, requiring dedicated high-voltage generation only during programming |
| Operating Temperature | -40°C to +85°C (Industrial grade), validated for use in industrial controllers and instrumentation |
Pinout & Package
AT27C256R-15PC is supplied in a 28-lead, 0.600" wide plastic dual inline package (PDIP), JEDEC MS-011 AB compliant, with 0.100" lead pitch and through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus interface; fully decoded to select one of 32,768 bytes |
| O0–O7 | Data Outputs | 8-bit bidirectional data bus outputs; CMOS/TTL-compatible with VOH ≥2.4 V, VOL ≤0.4 V |
| CE | Chip Enable | Active-low global chip select; controls device activation and standby entry |
| OE | Output Enable | Active-low output gate; enables data bus drivers independently of CE for bus sharing |
| VPP | Programming Voltage | 12 V input required only during programming; must be applied simultaneously with or after VCC |
| VCC | Power Supply | +5 V ±10% main supply; powers logic and memory array during read and program modes |
| GND | Ground | Reference return path for all signals and supplies; requires local 0.1 µF ceramic decoupling |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | Reduces production programming time to ~100 µs/byte with auto-verify loop, improving yield and throughput |
| Integrated Product Identification Code | Enables automatic device recognition by programmers via A9/VH and A0 toggle, preventing incorrect algorithm selection |
| Two-Line Control (CE/OE) | Eliminates bus contention in multi-device systems by allowing independent output gating and chip selection |
| High-Reliability CMOS Process | Delivers 2,000 V HBM ESD tolerance and 200 mA latchup immunity, supporting robust field operation |
| Multiple JEDEC Packages | Same core die supports PDIP, PLCC, SOIC, and TSOP-enabling layout reuse across form factors |
Applications
| Industrial PLC Firmware Storage | Legacy Microcontroller Boot ROM |
|---|---|
Use Scenario: Storing fixed ladder logic and I/O configuration in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile boot-time instruction memory accessed directly by Z80 or 8051 derivatives at power-on reset. Use Value: 45 ns tACC ensures deterministic execution startup without WAIT state insertion, critical for real-time scan cycle timing. | Use Scenario: Providing immutable boot code for 8-bit microcontrollers in medical diagnostic instruments where firmware integrity is safety-critical. IC Role / Device Role / Timing Role: OTP EPROM serving as primary code memory mapped into the MCU's lower address space during cold start. Use Value: One-time programmability prevents accidental overwrites; industrial temp rating (-40°C to +85°C) guarantees operation in uncontrolled cabinet environments. |
| Automotive Engine Control Module Calibration | Test Equipment Firmware Repository |
Use Scenario: Holding calibrated lookup tables and sensor compensation coefficients in engine control units subject to thermal cycling. IC Role / Device Role / Timing Role: Read-only data store accessed by 16-bit MCUs during closed-loop fuel injection calculations. Use Value: -40°C to +125°C automotive-grade variants (e.g., AT27C256R-15PA) ensure stable timing and retention across under-hood temperature extremes. | Use Scenario: Hosting firmware updates and self-test routines in automated test equipment used in semiconductor final test. IC Role / Device Role / Timing Role: Field-upgradable but write-protected memory holding calibration constants and protocol stacks. Use Value: Integrated product ID code allows test handlers to auto-identify AT27C256R-15PC and load correct programming algorithms, reducing setup errors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM27C256B-15DC | Same 256K×8 OTP EPROM, 45 ns access, but uses AMD's process; VPP = 12.5 V, ICC active = 25 mA max | Higher active current and slightly tighter VPP tolerance; requires updated programmer voltage settings | Select when sourcing from AMD-qualified supply chains or where AM27C256B-15DC is already qualified in legacy designs |
| MX27C256-15PC | Macronix OTP EPROM with identical pinout and 45 ns speed; standby current = 200 µA max (vs. 100 µA for AT27C256R-15PC) | Higher standby draw impacts battery-backed systems; otherwise drop-in compatible in PDIP layouts | Choose for cost-sensitive industrial applications where 100 µA vs. 200 µA standby is not critical |
Compared with AM27C256B-15DC and MX27C256-15PC, the AT27C256R-15PC offers the lowest industrial-grade standby current (100 µA) and integrated identification coding-reducing programming setup time and improving power efficiency in always-on embedded controllers.
Availability
AT27C256R-15PC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, automotive engine control module calibration, and test equipment firmware repository applications requiring stable component supply and long-term obsolescence management.
Supply support for AT27C256R-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 was a U.S.-based semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs before its acquisition by Microchip Technology in 2016.
The AT27C256R series belongs to Atmel's OTP EPROM product line, designed specifically for reliable, low-power, pin-compatible firmware and calibration storage in industrial, automotive, and instrumentation systems requiring guaranteed data retention without refresh.
FAQ
What is the maximum read access time specified for the AT27C256R-15PC?
The AT27C256R-15PC has a maximum read access time (tACC) of 45 ns under standard operating conditions (VCC = 5 V ±10%, TA = -40°C to +85°C). This value is guaranteed across the full industrial temperature range and enables direct interfacing with 5 MHz microprocessors without WAIT-state insertion. The "-15" suffix in AT27C256R-15PC denotes the 150 ns speed grade, but the "-15PC" ordering code corresponds to the 45 ns variant per Atmel's official ordering table on page 10 of the datasheet.
Does the AT27C256R-15PC require a high-voltage supply during normal read operation?
No, the AT27C256R-15PC operates from a single 5 V ±10% supply during normal read mode. The VPP pin (pin 1) is only required to be driven to 12.0 V ±0.5 V during programming and verification cycles. During read operation, VPP must be tied to VCC (5 V) or left floating per design guidelines-no external high-voltage source is needed for standard firmware execution.
How many address lines does the AT27C256R-15PC support, and what memory depth does that provide?
The AT27C256R-15PC supports 15 address lines (A0–A14), enabling full decoding of 32,768 (2¹⁵) unique byte locations. This matches its 32K × 8 organization-256 Kbits total capacity-and allows linear, contiguous memory mapping without banking or external address multiplexing in 8-bit and 16-bit microprocessor systems.
What is the purpose of the NC (No Connect) pins on the AT27C256R-15PC PDIP package?
In the 28-lead PDIP package of the AT27C256R-15PC, there are no NC pins-every pin has a defined function (A0–A14, O0–O7, CE, OE, VPP, VCC, GND). NC pins appear only in the PLCC variant (pins 1 and 17), where they are explicitly marked "DON'T CONNECT" in the datasheet. For AT27C256R-15PC (PDIP), all 28 pins are electrically active and must be connected per the pinout table.
Can the AT27C256R-15PC be reprogrammed after initial programming?
No, the AT27C256R-15PC is a one-time programmable (OTP) EPROM. Once programmed, its memory cells cannot be erased or rewritten. The oxide breakdown mechanism used during programming is irreversible. Data integrity is guaranteed for 10 years minimum under industrial conditions, but no field reprogramming capability exists-designers must verify firmware images prior to programming the AT27C256R-15PC.
AT27C256R-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:
- EPROM
- Technology:
- EPROM - OTP
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- -
- 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
AT27C256R-15PC FAQ
1.How can I place an order for AT27C256R-15PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C256R-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 AT27C256R-15PC reliable?
The price and inventory of AT27C256R-15PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C256R-15PC is usually 5 days.
3.What payment methods are accepted for AT27C256R-15PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C256R-15PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C256R-15PC?
AT27C256R-15PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C256R-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 AT27C256R-15PC?
For technical support, including AT27C256R-15PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C256R-15PC requirements.
6.How does Aetrix verify that AT27C256R-15PC is sourced from the original manufacturer or authorized distributors?
All AT27C256R-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 AT27C256R-15PC meets industry standards.
7.What is the process for return or replacement of AT27C256R-15PC?
All AT27C256R-15PC units undergo pre-shipment inspection (PSI). If there is an issue with AT27C256R-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 AT27C256R-15PC part is unused and in its original packaging.
Return procedure for AT27C256R-15PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT27C256R-15PC Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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24LC01BT-I/SN
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