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Microchip Technology AT27C256R-90PA
- Part No.:
- AT27C256R-90PA
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT27C256R-90PA.pdf
- Description:
- IC EPROM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,444
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Product details
Overview
AT27C256R-90PA from Microchip Technology (formerly Atmel) is a 32K × 8-bit one-time programmable EPROM used for firmware storage in microprocessor systems, featuring 45 ns read access time, 5V ±10% supply operation, and automotive-grade temperature range (–40°C to +125°C) in 28-lead PDIP package.
For engineers reviewing the AT27C256R-90PA datasheet, AT27C256R-90PA pinout, AT27C256R-90PA application, or AT27C256R-90PA equivalent, key selection criteria include OTP reliability, rapid programming (100 µs/byte), CMOS/TTL compatibility, dual-line control (CE/OE), and automotive qualification with 2,000V ESD protection.
Technical Context
The AT27C256R-90PA implements a standard OTP EPROM architecture with address decoding for A0–A14 (15-bit), 8-bit parallel data outputs (O0–O7), and two-level enable control (CE and OE) to prevent bus contention. It uses scaled CMOS technology for low-power operation and integrates a product identification code accessible via A9 and A0 toggling.
Programming requires VPP = 13.0 V ±0.25 V and VCC = 6.5 V ±0.25 V, with a Rapid™ algorithm applying 100 µs CE pulses per byte and up to 10 retries on verification failure. Read mode operates at single 5V supply with no external programming voltage needed.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8), enabling full firmware image storage for 8-bit microcontrollers without external memory expansion. |
| Read Access Time | 90 ns max (tACC), compatible with 11 MHz CPU buses without wait states in industrial and automotive systems. |
| Supply Voltage | 5 V ±10%, eliminating need for dedicated programming voltage during read operation and simplifying power design. |
| Standby Current | 100 µA max (ISB1), supporting low-power modes in battery-backed or energy-sensitive embedded applications. |
| Operating Temperature | –40°C to +125°C, qualified for under-hood automotive ECUs and industrial control units exposed to thermal stress. |
| ESD Protection | 2,000 V HBM, ensuring robustness against handling and board-level electrostatic discharge in manufacturing and field environments. |
| Programming Speed | 100 µs/byte typical (Rapid™ algorithm), reducing production programming cycle time versus legacy EPROMs. |
Pinout & Package
AT27C256R-90PA is packaged 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; selects one of 32,768 bytes during read or program operations. |
| O0–O7 | Data Outputs | 8-bit bidirectional data path in read mode; high-impedance when CE or OE is inactive. |
| CE | Chip Enable | Active-low global enable; disables outputs and reduces current to standby level when high. |
| OE | Output Enable | Active-low output gate; allows data to appear on O0–O7 only when CE is also active low. |
| 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 logic and outputs during read; elevated to 6.5 V during programming. |
| GND | Ground Reference | Common return path for VCC and VPP; requires local 0.1 µF ceramic decoupling per device. |
| NC | No Connect | Pins not internally bonded; must remain unconnected to avoid signal integrity or latch-up risk. |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | Reduces production programming time to ~100 µs/byte with automatic verify-and-retry, improving yield and throughput in firmware loading lines. |
| Integrated Product Identification Code | Two-byte electronic ID (0x1E manufacturer, 0x8C device) enables automated programmer recognition and eliminates manual part selection errors. |
| Dual-Line Control (CE/OE) | Enables clean bus sharing in multi-device systems by allowing independent gating of chip select and output drivers to prevent contention. |
| CMOS/TTL Compatibility | Accepts TTL-level inputs and drives TTL loads, ensuring interoperability with legacy 5V microcontrollers and peripheral logic without level shifters. |
| Automotive Temperature Range | Validated operation from –40°C to +125°C supports deployment in engine control modules, transmission controllers, and ADAS sensor nodes. |
Applications
| Engine Control Unit (ECU) | Industrial PLC Firmware Storage |
|---|---|
Use Scenario: Storing calibrated fuel injection maps and real-time diagnostic routines in gasoline/diesel engine management systems. IC Role / Device Role / Timing Role: Non-volatile firmware ROM providing deterministic 90 ns read latency to meet hard real-time deadlines in 16-bit MCU-based control loops. Use Value: Automotive qualification ensures reliable operation across thermal cycling and vibration; OTP prevents accidental overwrite during vehicle service. | Use Scenario: Holding ladder logic execution firmware and I/O configuration tables in modular programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Static instruction memory mapped into the PLC CPU's address space, accessed via standard 8-bit data bus with CE/OE handshaking. Use Value: Low 100 µA standby current extends uptime during brown-out conditions; 2,000 V ESD withstand protects against shop-floor static discharge. |
| Medical Infusion Pump Controller | Avionics Display Boot ROM |
Use Scenario: Hosting safety-critical dosing algorithms and calibration constants in Class II medical devices requiring regulatory traceability. IC Role / Device Role / Timing Role: Immutable boot-time firmware source ensuring deterministic startup behavior and preventing runtime corruption. Use Value: One-time programmability guarantees firmware integrity over 10+ year product lifecycle; automotive temp range covers extended operating environments. | Use Scenario: Storing display initialization firmware and font assets for cockpit multifunction displays in certified aircraft systems. IC Role / Device Role / Timing Role: Read-only memory mapped at reset vector address, delivering verified instructions within 90 ns to meet DO-254 timing budgets. Use Value: High-reliability CMOS process and 200 mA latchup immunity mitigate single-event effects in avionics power domains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT27C256B-90PA | Legacy revision with identical pinout, timing, and OTP functionality; lacks integrated product ID code and Rapid™ programming optimization. | Suitable for cost-sensitive legacy designs where ID code and fast programming are not required. | Select AT27C256R-90PA when automated programming validation or reduced production cycle time is critical. |
| MX27C256-90PC | Functionally equivalent 32K×8 OTP EPROM but with 28-lead PDIP and 90 ns access; no automotive temp grade or 2,000 V ESD rating. | Limited to commercial/industrial use; not qualified for under-hood or harsh-environment deployment. | Choose AT27C256R-90PA for automotive or high-reliability applications requiring extended temperature and ESD performance. |
Compared with AT27C256B-90PA, the AT27C256R-90PA adds programmable ID and faster programming; versus MX27C256-90PC, it delivers automotive qualification and enhanced ESD robustness-making it the sole choice for safety-critical, thermally demanding, or high-volume manufacturing contexts.
Availability
AT27C256R-90PA is available at Aetrix Electronics and suitable for automotive engine control, industrial PLC firmware storage, and medical device boot ROM applications requiring stable component supply across extended product lifecycles.
Supply support for AT27C256R-90PA 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 its legacy non-volatile memory portfolio, emphasizing reliability, long-term availability, and industrial-grade qualification.
The AT27C256R belongs to Atmel's OTP EPROM family designed for firmware storage in resource-constrained, high-reliability embedded systems where data immutability, thermal resilience, and deterministic timing are mandatory.
FAQ
What is the maximum read access time specified for the AT27C256R-90PA?
The AT27C256R-90PA has a maximum read access time (tACC) of 90 ns under standard operating conditions (VCC = 5 V ±10%, TA = –40°C to +125°C). This value is guaranteed across the full automotive temperature range and enables direct interfacing with 11 MHz microprocessors without wait-state insertion. The "-90" suffix in the part number explicitly denotes this speed grade.
Does the AT27C256R-90PA require a programming voltage during normal read operation?
No, the AT27C256R-90PA operates from a single 5 V ±10% supply during read mode. VPP (13.0 V) is required only during programming and must be applied simultaneously with or after VCC. In read mode, VPP is tied to VCC; the device draws less than 100 µA standby current and up to 20 mA active current at 5 MHz-no external high-voltage source is needed for system operation.
What package type is used for the AT27C256R-90PA?
The AT27C256R-90PA uses a 28-lead, 0.600" wide plastic dual inline package (PDIP), designated as package code "28P6" per Atmel's ordering information. It conforms to JEDEC standard MS-011 AB, features through-hole leads with 0.100" pitch, and is rated for automotive temperature operation (–40°C to +125°C).
How does the Rapid™ Programming Algorithm improve production efficiency for the AT27C256R-90PA?
The Rapid™ Programming Algorithm reduces average programming time to ~100 µs per byte by using optimized CE pulse widths and an embedded verify-and-retry loop. For the full 32K-byte array, this cuts total programming time by >30% versus legacy EPROM algorithms. The AT27C256R-90PA implements this natively-no external controller logic is required-and supports automated pass/fail reporting via the integrated product ID.
Is the AT27C256R-90PA pin-compatible with other speed grades in the same package?
Yes, all AT27C256R variants-including -45PA, -55PA, -70PA, -90PA, -12PA, and -15PA-in the 28P6 PDIP package share identical pinout, electrical interface, and functional behavior. Only the read access time (tACC) and corresponding AC timing parameters differ. System designs can interchange speed grades without PCB or firmware changes, provided timing margins accommodate the selected grade.
AT27C256R-90PA 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:
- 90 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-PDIP
AT27C256R-90PA FAQ
1.How can I place an order for AT27C256R-90PA through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C256R-90PA 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-90PA reliable?
The price and inventory of AT27C256R-90PA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C256R-90PA is usually 5 days.
3.What payment methods are accepted for AT27C256R-90PA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C256R-90PA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C256R-90PA?
AT27C256R-90PA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C256R-90PA 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-90PA?
For technical support, including AT27C256R-90PA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C256R-90PA requirements.
6.How does Aetrix verify that AT27C256R-90PA is sourced from the original manufacturer or authorized distributors?
All AT27C256R-90PA 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-90PA meets industry standards.
7.What is the process for return or replacement of AT27C256R-90PA?
All AT27C256R-90PA units undergo pre-shipment inspection (PSI). If there is an issue with AT27C256R-90PA, 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-90PA part is unused and in its original packaging.
Return procedure for AT27C256R-90PA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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