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Microchip Technology AT27C256R-70JC
- Part No.:
- AT27C256R-70JC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT27C256R-70JC.pdf
- Description:
- IC EPROM 256KBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,910
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Product details
Overview
AT27C256R-70JC from Atmel is a 32K × 8-bit one-time programmable EPROM (OTP EPROM) with 70 ns maximum access time, 5V ±10% supply operation, and JEDEC-standard 28-lead 600-mil PDIP packaging. It delivers fast read performance for microprocessor firmware storage in embedded control systems requiring non-volatile, pin-compatible ROM replacement.
For engineers reviewing the AT27C256R-70JC datasheet, AT27C256R-70JC pinout, AT27C256R-70JC application, or AT27C256R-70JC equivalent, key selection criteria include verified 70 ns tACC timing, VPP = 12.0 V programming voltage, industrial temperature range support, and dual-line CE/OE control architecture for bus contention avoidance.
Technical Context
The AT27C256R-70JC implements a CMOS-based OTP EPROM architecture with address decoding logic for A0–A14, eight bidirectional data outputs (O0–O7), and two independent enable controls (CE and OE). Its Rapid™ Programming Algorithm enables 100 µs/byte typical programming at VPP = 12.0 V and VCC = 6.5 V.
It features integrated product identification code accessible via A9 high-voltage mode (11.5–12.5 V), supporting automated programmer recognition. The device uses scaled CMOS technology to achieve ≤100 µA standby current and 20 mA active current at 5 MHz, with 2,000 V ESD protection and 200 mA latchup immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8), sufficient for boot code or configuration tables in 8-bit microcontroller systems |
| Access Time (tACC) | 70 ns max - ensures no WAIT states required on 14 MHz Z80 or 8 MHz 8086 bus cycles |
| Supply Voltage | 5 V ±10% - compatible with standard TTL/CMOS logic rails without regulation overhead |
| Standby Current | 100 µA max - enables low-power retention in battery-backed systems |
| Programming Voltage (VPP) | 12.0 V ±0.5 V - requires dedicated programming supply; not used during normal read operation |
| Operating Temperature | -40°C to +85°C (Industrial) - validated for factory automation and motor control environments |
| ESD Protection | 2,000 V HBM - meets IEC 61000-4-2 Level 2 for handling robustness |
Pinout & Package
AT27C256R-70JC is packaged in a 28-lead, 0.600-inch wide plastic dual in-line package (PDIP), per JEDEC MS-011 AB standard. Pin 1 is index-marked; pins are spaced 0.100 inch (2.54 mm) apart.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus interface; selects one of 32,768 memory locations |
| O0–O7 | Data Outputs | 8-bit bidirectional data bus; outputs valid only when CE = OE = low |
| CE | Chip Enable | Primary chip select; disables outputs and reduces current draw when high |
| OE | Output Enable | Secondary output gate; allows shared bus operation with other devices |
| VPP | Programming Voltage | 12 V input required only during programming; must be applied simultaneously with VCC |
| VCC | Power Supply | +5 V supply; powers internal logic and drives outputs |
| GND | Ground | Reference return path for all signals and supplies |
| NC | No Connect | Pins 1 and 17 in PLCC variant are unconnected; not present in PDIP version |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | 100 µs/byte typical - cuts firmware update time by >5× vs. legacy EPROMs |
| Integrated Product ID Code | Manufacturer byte (0x1E) and device code (0x8C) - enables auto-detection in universal programmers |
| Two-Line Control (CE/OE) | Independent enable logic - eliminates bus contention in multi-device memory maps |
| CMOS/TTL Compatibility | VIL ≤ 0.8 V, VIH ≥ 2.0 V - interoperates with both 5 V logic families without level shifters |
| High-Reliability Packaging | 200 mA latchup immunity and 2 kV ESD - suitable for industrial PCBs with noisy power domains |
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 deterministic 70 ns read access to instruction fetch pipeline. Use Value: Eliminates reliance on external EEPROM or flash, reducing BOM count and eliminating wear-out concerns in fixed-function firmware. | Use Scenario: Hosting startup code and hardware initialization routines for Z80, 8085, or 68000-based embedded controllers. IC Role / Device Role / Timing Role: Primary read-only program memory mapped into CPU address space with zero-wait-state timing. Use Value: Guarantees consistent boot behavior across temperature and voltage variations due to OTP reliability and tight AC specs. |
| Automotive Engine Control Module (ECM) | Medical Diagnostic Instrument BIOS |
Use Scenario: Holding calibration constants and safety-critical lookup tables in engine management units operating at -40°C to +125°C. IC Role / Device Role / Timing Role: OTP-configurable parameter store accessed during cold-start sequence before RAM initialization. Use Value: Meets AEC-Q100 stress requirements via industrial-grade packaging and 200 mA latchup immunity. | Use Scenario: Securing boot firmware and self-test routines in portable ultrasound or patient monitor systems. IC Role / Device Role / Timing Role: Tamper-resistant, non-rewritable BIOS image ensuring regulatory compliance and revision control. Use Value: One-time programmability prevents accidental or malicious firmware corruption during field service or 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-70DC | 70 ns access, same 32K×8 organization, but uses AMD's proprietary programming algorithm and lacks integrated ID code | Requires custom programming setup; no auto-identification in standard programmers | Select when legacy AMD toolchain compatibility is required and ID code is unnecessary |
| MX27C256-70PC | 70 ns access, identical pinout and DC specs, but rated only for commercial temperature (0°C to +70°C) | Not qualified for industrial or automotive thermal cycling or long-term storage at elevated temperatures | Select only for cost-sensitive consumer electronics where extended temperature operation is not required |
Compared with AM27C256B-70DC and MX27C256-70PC, the AT27C256R-70JC provides guaranteed Rapid™ programming verification, built-in manufacturer/device ID bytes, and full industrial temperature qualification - making it the preferred choice for production systems requiring traceable firmware loading and environmental resilience.
Availability
AT27C256R-70JC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, and automotive engine control module applications requiring stable component supply and long-term lifecycle support.
Supply support for AT27C256R-70JC 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 company specializing in microcontrollers, non-volatile memory, and secure authentication ICs before its acquisition by Microchip Technology in 2016.
The AT27C256R belongs to Atmel's OTP EPROM product line, designed specifically for reliable, low-cost, pin-compatible replacement of UV-erasable EPROMs in fixed-function embedded systems where firmware immutability and read speed are critical.
FAQ
What is the programming voltage requirement for AT27C256R-70JC?
The AT27C256R-70JC requires VPP = 12.0 V ±0.5 V during programming, applied simultaneously with VCC. This voltage is not used during normal read operation. The device incorporates VID sensing on A9 to validate correct VPP level before accepting programming commands, ensuring data integrity and preventing over-programming.
Does AT27C256R-70JC support automatic device identification in programming equipment?
Yes, the AT27C256R-70JC includes an integrated product identification code: Manufacturer ID = 0x1E and Device Code = 0x8C. These bytes are accessed by setting A9 to 11.5–12.5 V while holding A1–A14 low and toggling A0 - enabling universal programmers to auto-detect and configure correct algorithms and voltages for AT27C256R-70JC.
Can AT27C256R-70JC operate without external decoupling capacitors?
No. Per the datasheet, AT27C256R-70JC requires a 0.1 µF ceramic capacitor between VCC and GND, placed as close as possible to the device, plus a 4.7 µF bulk electrolytic capacitor near the power entry point for arrays. Omitting these risks transient-induced non-conformance due to switching noise on CE/OE lines.
What is the maximum active current draw of AT27C256R-70JC at 5 MHz?
The AT27C256R-70JC draws a maximum of 20 mA active current (ICC) at 5 MHz, with IOUT = 0 mA and CE = OE = VIL. Typical active current is lower - approximately 8 mA - due to Atmel's scaled CMOS process, supporting energy-efficient designs in thermally constrained enclosures.
Is AT27C256R-70JC compatible with TTL-level microprocessor buses?
Yes, AT27C256R-70JC features CMOS and TTL compatible inputs and outputs: VIH ≥ 2.0 V, VIL ≤ 0.8 V, VOH ≥ 2.4 V (at -400 µA), and VOL ≤ 0.4 V (at 2.1 mA). This ensures direct interfacing with 5 V TTL buses such as those found in 8086, Z80, and 68000 systems without level-shifting circuitry.
AT27C256R-70JC 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:
- 70 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT27C256R-70JC FAQ
1.How can I place an order for AT27C256R-70JC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C256R-70JC 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-70JC reliable?
The price and inventory of AT27C256R-70JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C256R-70JC is usually 5 days.
3.What payment methods are accepted for AT27C256R-70JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C256R-70JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C256R-70JC?
AT27C256R-70JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C256R-70JC 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-70JC?
For technical support, including AT27C256R-70JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C256R-70JC requirements.
6.How does Aetrix verify that AT27C256R-70JC is sourced from the original manufacturer or authorized distributors?
All AT27C256R-70JC 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-70JC meets industry standards.
7.What is the process for return or replacement of AT27C256R-70JC?
All AT27C256R-70JC units undergo pre-shipment inspection (PSI). If there is an issue with AT27C256R-70JC, 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-70JC part is unused and in its original packaging.
Return procedure for AT27C256R-70JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT27C256R-70JC Tags
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