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Microchip Technology AT27C256R-15JI
- Part No.:
- AT27C256R-15JI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT27C256R-15JI.pdf
- Description:
- IC EPROM 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,229
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Product details
Overview
AT27C256R-15JI from Microchip Technology (formerly Atmel) is a 32K × 8-bit one-time programmable EPROM used for non-volatile firmware storage in microprocessor systems. It delivers 45 ns read access time, operates on a single 5V ±10% supply, and supports industrial temperature range (–40°C to +85°C) in a 28-lead plastic DIP package. It enables fast, latchup-immune boot code access without wait states.
For engineers reviewing the AT27C256R-15JI datasheet, AT27C256R-15JI pinout, AT27C256R-15JI application, or AT27C256R-15JI equivalent, key selection criteria include verified 45 ns tACC timing, CMOS/TTL I/O compatibility, VPP-programmable OTP architecture, integrated product identification code, and JEDEC-standard 28P6 DIP packaging with NC pin handling per PLCC/PDIP variants.
Technical Context
The AT27C256R-15JI implements a parallel-addressed OTP EPROM architecture with dual-line control (CE and OE) enabling bus contention avoidance in shared-data-bus systems. Its Rapid™ programming algorithm achieves 100 µs/byte typical write speed using 13.0 V VPP and 6.5 V VCC during programming cycles.
It features electrically identifiable manufacturer and device codes via A9/VH and A0 toggling, supports high-reliability operation with 2,000V ESD protection and 200 mA latchup immunity, and requires decoupling with 0.1 µF ceramic + 4.7 µF bulk capacitors per system design guidelines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8), sufficient for full boot ROM or configuration tables in 8-bit embedded controllers |
| Read Access Time | 45 ns max - eliminates WAIT states on 5 MHz Z80, 8086, or 68000-based systems |
| Supply Voltage | 5V ±10% - compatible with standard TTL/CMOS logic rails without regulation overhead |
| Standby Current | 100 µA max - enables low-power retention in battery-backed or intermittent-operation systems |
| Active Current | 20 mA max at 5 MHz - supports sustained read bursts without thermal derating in compact PCB layouts |
| VPP Programming Voltage | 13.0 V ±0.25 V - requires dedicated high-voltage programming circuitry, not supplied by host MCU |
| Operating Temperature | –40°C to +85°C - qualified for industrial control panels, motor drives, and factory automation equipment |
Pinout & Package
AT27C256R-15JI is packaged in a 28-lead, 0.600" wide plastic dual in-line package (PDIP), per JEDEC MS-011 AB standard. Pin 1 is index-marked; pins 1 and 17 are no-connect in PLCC variants but are functional address lines (A0, A10) in PDIP.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus interface supporting full 32K-byte addressing; TTL/CMOS compatible thresholds |
| O0–O7 | Data Outputs | 8-bit bidirectional data bus outputs with VOH ≥2.4 V @ –400 µA and VOL ≤0.4 V @ 2.1 mA |
| CE | Chip Enable | Active-low chip select; controls device enable/disable state and initiates programming when pulsed |
| OE | Output Enable | Active-low output gate; allows multiple devices on same data bus without contention |
| VPP | Programming Voltage | 13.0 V input required only during programming; must be applied simultaneously with or after VCC |
| VCC | Power Supply | +5 V ±10% main supply; powers both read and program modes (6.5 V during programming) |
| GND | Ground Reference | Signal and power return; requires local 0.1 µF ceramic decoupling per device |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | 100 µs/byte typical - reduces firmware update time by >5× vs. legacy EPROMs, with up to 10 reprogram attempts per byte |
| Integrated Product Identification Code | Manufacturer ID (0x1E) and Device Code (0x8C) readable via A9=12.0 V and A0 toggle - enables automated programmer validation |
| Two-Line Control Architecture | Independent CE and OE inputs - permits flexible memory mapping and eliminates bus conflicts in multi-peripheral systems |
| High-Reliability Process | 2,000 V HBM ESD rating and 200 mA latchup immunity - ensures robustness in noisy industrial environments |
| JEDEC-Standard Packaging Options | 28P6 PDIP, 32J PLCC, 28R SOIC, 28T TSOP - supports legacy socket reuse, surface-mount migration, and space-constrained designs |
Applications
| Industrial PLC Firmware Storage | Legacy Microcontroller Boot ROM |
|---|---|
Use Scenario: Storing ladder logic interpreter and I/O mapping tables in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Non-volatile boot memory providing immediate instruction fetch at power-on, synchronized to 5 MHz CPU clock. Use Value: 45 ns tACC ensures zero-wait-state execution of initialization routines, improving system startup repeatability and reducing watchdog timeout risk. | Use Scenario: Holding fixed BIOS or monitor firmware for Z80- or 8085-based development boards and test equipment. IC Role / Device Role / Timing Role: Parallel-addressed OTP EPROM acting as primary code store, directly mapped into CPU address space. Use Value: Single 5V supply simplifies power design; CMOS/TTL compatibility avoids level-shifter components in mixed-logic systems. |
| Automated Test Equipment Configuration | Embedded Instrumentation Calibration Data |
Use Scenario: Storing calibration constants, test sequence definitions, and safety interlock logic in benchtop ATE platforms. IC Role / Device Role / Timing Role: Read-only configuration memory accessed during self-test and setup phases. Use Value: Industrial temperature rating (–40°C to +85°C) guarantees reliable parameter retrieval across environmental chambers and production floor conditions. | Use Scenario: Retaining sensor offset/gain coefficients and linearization tables in portable multimeters and oscilloscopes. IC Role / Device Role / Timing Role: Static data repository queried once at power-up and cached in RAM for runtime use. Use Value: 100 µA max standby current extends battery life in handheld instruments; OTP nature prevents accidental corruption during field updates. |
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 32K×8 organization, 45 ns access, but uses AMD's process with 12.5 V VPP and different ID code protocol | Requires AMD-specific programming voltage sequencing and verification logic; not drop-in in Atmel-optimized programmers | Select if existing toolchain supports AMD EPROMs and board layout accommodates identical 28P6 footprint |
| MX27C256-15PC | Macronix variant with identical timing and pinout, but specifies 25 mA active current and lacks integrated ID code | No built-in manufacturer/device identification - requires external firmware lookup or manual part verification during programming | Choose for cost-sensitive industrial builds where ID code functionality is unused and 5 mA higher ICC is acceptable |
Compared with AM27C256B-15DC and MX27C256-15PC, the AT27C256R-15JI offers guaranteed Rapid™ programming compatibility, on-chip identification for automated tooling, and tighter 20 mA active current spec-making it preferred for high-mix manufacturing and legacy system repair where Atmel toolchains dominate.
Availability
AT27C256R-15JI is available at Aetrix Electronics and suitable for industrial control systems, legacy microcontroller boot applications, and automated test equipment requiring stable component supply over extended production lifecycles.
Supply support for AT27C256R-15JI 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 acquired Atmel in 2016 and maintains legacy EPROM product lines for industrial and aerospace continuity. The company specializes in secure, reliable, long-lifecycle semiconductor solutions.
The AT27C256R-15JI belongs to Atmel's 27C-series OTP EPROM family, designed specifically for firmware storage in cost-sensitive, high-reliability embedded systems where flash endurance or reprogrammability is unnecessary.
FAQ
What is the maximum operating frequency supported by the AT27C256R-15JI?
The AT27C256R-15JI does not operate at a clock frequency itself-it is a static memory device. Its 45 ns access time supports reliable interfacing with microprocessors running up to approximately 5 MHz (200 ns cycle time), assuming proper address setup/hold timing and no wait states. System-level timing depends on CE and OE assertion timing, not an internal clock.
Can the AT27C256R-15JI be reprogrammed multiple times?
No-the AT27C256R-15JI is a one-time programmable (OTP) EPROM. Once programmed, its contents cannot be erased or rewritten. UV-erasable EPROMs (e.g., 27C256 without 'R') require quartz-window packages and UV exposure; the 'R' suffix denotes plastic-package OTP construction with no erase capability.
Is the AT27C256R-15JI pin-compatible with the older AT27C256?
Yes-the AT27C256R-15JI maintains identical pinout, signal definitions, and DC/AC specifications as the original AT27C256 across all JEDEC packages (PDIP, PLCC, SOIC, TSOP). The 'R' denotes process and reliability enhancements-not functional or mechanical changes-so it is a direct replacement in existing designs.
What voltage is required on VPP during programming of the AT27C256R-15JI?
The AT27C256R-15JI requires a precisely regulated 13.0 V ±0.25 V on VPP during programming, applied simultaneously with or after VCC (6.5 V ±0.25 V). This voltage is not used during normal read operation. A 0.1 µF capacitor between VPP and GND is mandatory to suppress transients per the datasheet.
Does the AT27C256R-15JI support automatic device identification in programming hardware?
Yes-the AT27C256R-15JI includes an Integrated Product Identification Code. By setting A9 to 12.0 V and toggling A0, programmers can read Manufacturer ID (0x1E) and Device Code (0x8C) bytes. This enables auto-detection and algorithm selection in industry-standard EPROM programmers like BP Microsystems or Xeltek units.
AT27C256R-15JI 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:
- 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:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT27C256R-15JI FAQ
1.How can I place an order for AT27C256R-15JI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C256R-15JI 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-15JI reliable?
The price and inventory of AT27C256R-15JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C256R-15JI is usually 5 days.
3.What payment methods are accepted for AT27C256R-15JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C256R-15JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C256R-15JI?
AT27C256R-15JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C256R-15JI 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-15JI?
For technical support, including AT27C256R-15JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C256R-15JI requirements.
6.How does Aetrix verify that AT27C256R-15JI is sourced from the original manufacturer or authorized distributors?
All AT27C256R-15JI 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-15JI meets industry standards.
7.What is the process for return or replacement of AT27C256R-15JI?
All AT27C256R-15JI units undergo pre-shipment inspection (PSI). If there is an issue with AT27C256R-15JI, 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-15JI part is unused and in its original packaging.
Return procedure for AT27C256R-15JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT27C256R-15JI Tags
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