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Microchip Technology AT27C256R-90TI
- Part No.:
- AT27C256R-90TI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT27C256R-90TI.pdf
- Description:
- IC EPROM 256KBIT PARALLEL 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,098
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Product details
Overview
AT27C256R-90TI from Microchip Technology (formerly Atmel) is a 32K × 8-bit one-time programmable EPROM with 45 ns read access time, 5V ±10% supply, and industrial temperature range (–40°C to +85°C). It features dual-line control (CE/OE), rapid programming (100 µs/byte), and JEDEC-standard 28-pin SOIC packaging for embedded firmware storage in microprocessor systems.
For engineers reviewing the AT27C256R-90TI datasheet, AT27C256R-90TI pinout, AT27C256R-90TI application, or AT27C256R-90TI equivalent, key selection criteria include verified 45 ns tACC timing, 100 µA max standby current, VPP = 12.0 V programming voltage, CMOS/TTL I/O compatibility, and industrial-grade reliability with 2,000V ESD protection.
Technical Context
The AT27C256R-90TI implements a standard OTP EPROM architecture with address decoding for A0–A14, eight bidirectional data outputs (O0–O7), and two active-low control lines (CE, OE) enabling bus contention avoidance. Its Rapid™ programming algorithm uses 100 µs CE pulses at VPP = 12.0 V for byte-level programming.
It supports product identification via A9 high-voltage mode (11.5–12.5 V) and A0 toggling to read manufacturer (0x1E) and device (0x8C) codes. The device operates exclusively in 5V read mode but requires elevated VPP during programming, with strict sequencing (VCC applied before/with VPP).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 32K × 8 bits (262,144-bit OTP EPROM) |
| Read Access Time | 45 ns maximum - eliminates WAIT states in 5 MHz microprocessor systems |
| Supply Voltage | 5V ±10% - single-supply operation in standard logic environments |
| Standby Current | 100 µA max - enables low-power firmware retention in always-on systems |
| Active Current | 20 mA max at 5 MHz - compatible with standard 5V bus drive capability |
| Programming Voltage | VPP = 12.0 ±0.5 V - required only during programming; not used in read mode |
| ESD Protection | 2,000V HBM - ensures robust handling during board assembly and field service |
Pinout & Package
AT27C256R-90TI is packaged in a 28-lead, 0.330" wide plastic gull-wing small outline (SOIC), per JEDEC MS-012 standard. Pin pitch is 1.27 mm, body width 7.5 mm, and total length 17.9 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus for selecting one of 32,768 memory locations |
| O0–O7 | Data Outputs | 8-bit bidirectional data bus - outputs valid when CE and OE are low |
| CE | Chip Enable | Active-low global enable - disables outputs and reduces current to standby level when high |
| OE | Output Enable | Active-low output gate - controls data bus drive without affecting internal state or power |
| VPP | Programming Voltage | 12.0 V input required only during programming; must be sequenced with VCC |
| VCC | Power Supply | +5V supply for read operations; powers all internal logic and I/O buffers |
| GND | Ground | Reference return path for VCC and VPP; requires local 0.1 µF ceramic decoupling |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | 100 µs/byte typical - reduces firmware update time and improves production throughput |
| Integrated Product ID Code | Manufacturer (0x1E) and device (0x8C) codes readable via A9/A0 - enables automated programmer validation |
| Two-Line Control (CE/OE) | Independent chip and output enables - prevents bus contention in multi-device systems |
| Industrial Temperature Range | –40°C to +85°C - qualified for use in factory automation, motor drives, and industrial controllers |
| CMOS/TTL Compatible I/O | VIL ≤ 0.8 V, VIH ≥ 2.0 V - interoperable with legacy 5V microcontrollers and FPGAs without level shifters |
Applications
| Industrial PLC Firmware Storage | Legacy Microcontroller Boot ROM |
|---|---|
Use Scenario: Storing fixed ladder logic and I/O mapping in programmable logic controllers deployed in factory environments with ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: Nonvolatile boot-time firmware repository accessed during cold start and system reset sequences. Use Value: 45 ns access time ensures deterministic boot latency; industrial temp rating guarantees operation across thermal cycling in unconditioned enclosures. | Use Scenario: Providing immutable startup code for 8051- and Z80-based embedded controllers in test equipment and instrumentation. IC Role / Device Role / Timing Role: Read-only memory mapped at address 0x0000, delivering instruction opcodes directly to CPU address/data bus. Use Value: CMOS/TTL compatibility eliminates interface logic; 100 µA standby current extends battery-backed runtime during power-loss events. |
| Automotive Body Control Module EEPROM Backup | Medical Device Calibration Data Storage |
Use Scenario: Holding configuration data for window lift, mirror positioning, and lighting profiles in automotive BCMs operating across –40°C to +85°C. IC Role / Device Role / Timing Role: Secondary nonvolatile storage accessed only during initialization or reprogramming - not real-time. Use Value: OTP architecture prevents accidental overwrites; 2,000V ESD protection withstands assembly line static discharge and service technician handling. | Use Scenario: Storing factory-calibrated sensor offsets and gain coefficients in portable diagnostic devices requiring long-term data integrity. IC Role / Device Role / Timing Role: Immutable reference data store read once per power cycle to initialize ADC and signal chain compensation. Use Value: High-reliability CMOS process ensures >20-year data retention; no refresh or wear-leveling management required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT27C256B-90TI | Successor revision with identical timing, package, and pinout; improved programming yield and tighter VPP tolerance (12.0 ±0.3 V vs. ±0.5 V) | No functional change; validated for same industrial firmware roles | Select AT27C256B-90TI for new designs where latest Atmel revision assurance is required |
| MX27C256-90PC | 28-pin PDIP package only; 45 ns tACC, same 5V/12V dual-supply operation; no PLCC/SOIC/TSOP variants | Requires PCB layout change for SOIC footprint; suitable for through-hole prototyping or legacy repair | Choose MX27C256-90PC only when PDIP mounting is mandatory and SOIC compatibility is not needed |
Compared with AT27C256R-90TI, the AT27C256B-90TI offers enhanced manufacturing consistency without design changes, while MX27C256-90PC provides identical electrical performance in a through-hole package - making the former a drop-in upgrade and the latter a mechanical alternative requiring layout revision.
Availability
AT27C256R-90TI is available at Aetrix Electronics and suitable for industrial control systems, legacy microcontroller boot applications, and medical device calibration storage requiring stable component supply across extended lifecycle programs.
Supply support for AT27C256R-90TI 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 full support for legacy Atmel memory products including the AT27C256R series.
The AT27C256R product line was designed for cost-sensitive, high-reliability embedded systems requiring immutable firmware storage with fast 5V read access and field-programmable capability using standard EPROM programmers.
FAQ
What is the maximum read access time specified for AT27C256R-90TI?
The AT27C256R-90TI has a maximum read access time (tACC) of 45 ns under standard conditions (VCC = 5V ±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 "-90" speed grade suffix explicitly denotes this 45 ns timing specification, confirmed in the official Atmel ordering table and AC characteristics table.
Does AT27C256R-90TI require a programming voltage during normal operation?
No, AT27C256R-90TI operates solely on a 5V ±10% supply during read mode. VPP (12.0 V) is required only during programming and verification cycles. In normal system operation - including power-up, standby, and active read - VPP must be tied to VCC or grounded per datasheet guidance. Applying VPP during read mode risks undefined behavior or damage.
What package type is used by AT27C256R-90TI?
AT27C256R-90TI uses a 28-lead plastic gull-wing small outline integrated circuit (SOIC) package, designated as "28R" in Atmel's ordering nomenclature. Its dimensions conform to JEDEC MS-012, with 1.27 mm lead pitch, 7.5 mm body width, and 17.9 mm length. This surface-mount package supports automated assembly and replaces through-hole PDIP in space-constrained industrial designs.
Can AT27C256R-90TI be used in automotive applications?
The AT27C256R-90TI is rated for industrial temperature range (–40°C to +85°C), not automotive (–40°C to +125°C). While some automotive subsystems operate within the industrial range, AT27C256R-90TI lacks AEC-Q100 qualification and is not recommended for under-hood or safety-critical modules. For automotive use, select AT27C256R-90RA (automotive-grade variant) instead.
How does the Integrated Product Identification Code function in AT27C256R-90TI?
The AT27C256R-90TI implements an electronic ID code accessible by asserting A9 = 12.0 V (VIH = 11.5–12.5 V) and toggling A0 between low and high while holding all other address lines low. This returns manufacturer ID 0x1E and device ID 0x8C on O7–O0. The feature enables automatic algorithm selection in industry-standard EPROM programmers and verifies correct device loading during production programming.
AT27C256R-90TI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tray
- 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 ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSOP
AT27C256R-90TI FAQ
1.How can I place an order for AT27C256R-90TI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C256R-90TI 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-90TI reliable?
The price and inventory of AT27C256R-90TI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C256R-90TI is usually 5 days.
3.What payment methods are accepted for AT27C256R-90TI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C256R-90TI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C256R-90TI?
AT27C256R-90TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C256R-90TI 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-90TI?
For technical support, including AT27C256R-90TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C256R-90TI requirements.
6.How does Aetrix verify that AT27C256R-90TI is sourced from the original manufacturer or authorized distributors?
All AT27C256R-90TI 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-90TI meets industry standards.
7.What is the process for return or replacement of AT27C256R-90TI?
All AT27C256R-90TI units undergo pre-shipment inspection (PSI). If there is an issue with AT27C256R-90TI, 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-90TI part is unused and in its original packaging.
Return procedure for AT27C256R-90TI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT27C256R-90TI 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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