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Microchip Technology AT27LV256A-55RC
- Part No.:
- AT27LV256A-55RC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.342", 8.69mm Width)
- Datasheet:
-
AT27LV256A-55RC.pdf
- Description:
- IC EPROM 256KBIT PARALLEL 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,268
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Product details
Overview
AT27LV256A-55RC from Atmel is a 256K-bit (32K × 8) one-time programmable EPROM optimized for low-voltage battery-powered systems, featuring 55 ns read access time, dual 3.0–3.6V or 4.5–5.5V supply operation, and JEDEC-standard 28-pin SOIC packaging. It delivers TTL-compatible outputs at 3.0V and supports rapid programming at 100 µs/byte.
For engineers reviewing the AT27LV256A-55RC datasheet, AT27LV256A-55RC pinout, AT27LV256A-55RC application, or AT27LV256A-55RC equivalent, key selection criteria include its 55 ns access timing, 20 µA max standby current at 3.6V, pin compatibility with AT27C256R, TSOP/SOIC/PLCC package flexibility, and integrated product identification code for automated programming.
Technical Context
The AT27LV256A-55RC implements a CMOS OTP EPROM architecture with two-line control (CE/OE), enabling bus contention prevention in shared-memory systems. Its dual-voltage design allows seamless integration into mixed-supply environments-operating at 3.3V for portable devices while maintaining TTL-level output compatibility with 5V logic.
It uses Atmel's Rapid™ Programming Algorithm requiring VCC = 6.5V and VPP = 13.0V during programming, with built-in product identification (Manufacturer ID = 0x1E, Device ID = 0x8C) for algorithm auto-selection in industry-standard programmers. Standby mode is activated by CE = VIH, reducing ICC to ≤20 µA at 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8) - supports firmware storage for microcontrollers with up to 32 KB code space. |
| Read Access Time | 55 ns max at VCC = 3.0–3.6V - enables direct interface with 12–18 MHz microcontrollers without wait states. |
| Supply Voltage Range | 3.0–3.6V or 4.5–5.5V - eliminates level-shifting in dual-voltage card designs (e.g., PCMCIA, ISA add-in cards). |
| Standby Current | 20 µA max at VCC = 3.6V - extends battery life in handheld instruments and portable test equipment. |
| Active Power Dissipation | 29 mW max at 5 MHz, VCC = 3.6V - reduces thermal load in dense memory arrays on industrial control PCBs. |
| Programming Speed | 100 µs/byte typical - cuts firmware update time by >80% vs. legacy 5V EPROMs using standard programmers. |
| ESD Protection | 2,000V HBM - ensures robustness during manual handling and board assembly in non-EPA environments. |
Pinout & Package
AT27LV256A-55RC is supplied in a 28-lead, 0.330" wide plastic gull-wing small outline (SOIC) package per JEDEC MS-012, with 1.27 mm lead pitch and body dimensions 17.9 × 7.6 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word decoding; compatible with Z80, 8051, and 68K family address lines. |
| O0–O7 | Data Outputs | 8-bit bidirectional data bus; TTL-compatible outputs drive standard logic loads without buffers at 3.0V. |
| CE | Chip Enable | Active-low chip select; enables memory access only when asserted-critical for multi-device memory mapping. |
| OE | Output Enable | Active-low output gate; decouples data bus during transfers to prevent contention with other peripherals. |
| VCC | Power Supply | Primary supply input; must be applied before/with VPP during programming to avoid latchup. |
| VPP | Programming Voltage | 13.0V programming supply; requires external 0.1 µF ceramic capacitor to ground for transient suppression. |
| GND | Ground Reference | Signal and power return; requires dedicated low-inductance path to minimize noise coupling into read timing. |
| NC | No Connect | Pins 1 and 28 are unconnected-must remain floating; no routing or stitching allowed. |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Pin Compatibility | Direct replacement for AT27C256R in existing 28-pin SOIC footprints-no PCB redesign required. |
| Rapid™ Programming | 100 µs/byte typical programming time reduces production line cycle time and improves yield in high-volume programming. |
| Integrated ID Code | Manufacturer ID (0x1E) and Device ID (0x8C) enable automatic algorithm selection in universal programmers-eliminates manual setup errors. |
| Two-Line Control Logic | Independent CE and OE inputs allow flexible memory arbitration in systems with DMA or multiple masters. |
| High-Reliability Process | 200 mA latchup immunity and 2 kV ESD rating ensure stable operation in industrial environments with noisy power rails. |
Applications
| Industrial PLC Firmware Storage | Portable Medical Instrument Boot Memory |
|---|---|
Use Scenario: Storing fixed ladder logic and I/O configuration tables in DIN-rail mounted programmable logic controllers operating in factory-floor environments with 0–70°C ambient range. IC Role / Device Role / Timing Role: Nonvolatile boot ROM providing deterministic startup sequence and real-time control code execution without external initialization delay. Use Value: 55 ns access time enables sub-microsecond instruction fetches for fast scan-cycle response; 20 µA standby current minimizes auxiliary power draw during PLC sleep modes. | Use Scenario: Holding calibrated sensor algorithms and device configuration in handheld blood glucose meters and pulse oximeters powered by coin-cell batteries. IC Role / Device Role / Timing Role: Low-voltage OTP EPROM delivering verified firmware at 3.0V-enabling direct interface with 3.3V microcontrollers without voltage translation. Use Value: Dual-supply operation allows same BOM across commercial and industrial variants; 29 mW active power prevents thermal drift in sealed medical enclosures. |
| Legacy ISA Bus Expansion Card BIOS | Automotive Diagnostic Tool Bootloader |
Use Scenario: Providing BIOS and peripheral initialization code in retro-computing expansion cards (e.g., SCSI host adapters) designed for 5V ISA slots with optional 3.3V support. IC Role / Device Role / Timing Role: Pin-compatible drop-in upgrade for AT27C256R-based designs-retaining identical timing and signal integrity. Use Value: TTL-level outputs at 3.0V ensure interoperability with 5V ISA bus signaling; JEDEC SOIC footprint simplifies rework of legacy boards. | Use Scenario: Storing bootloader firmware in OBD-II diagnostic tools used across vehicle models with varying ECU power architectures (12V switched, 5V regulated, or 3.3V LDO-derived). IC Role / Device Role / Timing Role: Dual-voltage OTP memory enabling single hardware design to operate in both 5V automotive test benches and 3.3V embedded tool modules. Use Value: Rapid programming supports field firmware updates via JTAG-to-EPROM interfaces; integrated ID code prevents misprogramming in multi-device production lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT27C256R-70PC | 5V-only operation (4.5–5.5V); 70 ns access; 28-pin PDIP package; no low-voltage capability. | Requires 5V supply and level shifters for 3.3V systems; unsuitable for battery-powered designs. | Select only for legacy 5V-only systems where AT27LV256A-55RC's low-voltage features are unnecessary. |
| MX29LV256ETTI-70G | 3.3V flash memory (not OTP); 70 ns access; 48-pin TSOP; supports in-system erase/rewrite. | Reprogrammable flash replaces OTP use case; requires different command protocol and erase management. | Choose when firmware updates are needed post-deployment; not a direct functional substitute due to non-OTP architecture. |
Compared with AT27C256R-70PC and MX29LV256ETTI-70G, the AT27LV256A-55RC uniquely combines 55 ns speed, true OTP security, dual-voltage operation, and JEDEC SOIC pinout-making it optimal for cost-sensitive, battery-aware, and legacy-compatible firmware storage where reprogramming is prohibited.
Availability
AT27LV256A-55RC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, portable medical instrument boot memory, and legacy ISA bus expansion card BIOS requiring stable component supply and long-term obsolescence management.
Supply support for AT27LV256A-55RC 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, nonvolatile memory, and analog ICs, acquired by Microchip Technology in 2016.
The AT27LV256A product line delivers low-power, pin-compatible OTP EPROMs for embedded systems requiring secure, unalterable firmware storage with minimal power overhead and broad voltage compatibility.
FAQ
What is the maximum operating temperature range for the AT27LV256A-55RC?
The AT27LV256A-55RC is rated for industrial temperature operation from –40°C to +85°C. This specification is confirmed in the Ordering Information table and DC Operating Conditions section of the datasheet, where the "-55RC" suffix explicitly denotes the industrial-grade variant with extended thermal tolerance-critical for deployment in automotive under-hood modules or factory automation controllers.
Can the AT27LV256A-55RC be operated at 3.0V and still produce TTL-compatible outputs?
Yes, the AT27LV256A-55RC produces TTL-compatible outputs (VOH ≥ 2.4V, VOL ≤ 0.4V) when operated at VCC = 3.0V, as verified in the DC Operating Characteristics table under "VCC = 3.0V to 3.6V" conditions. This enables direct interfacing with standard 5V TTL logic without level shifters-essential for mixed-voltage backplane designs like PCMCIA cards.
Is the AT27LV256A-55RC pin-compatible with the AT27C256R, and what does that mean for PCB layout?
Yes, the AT27LV256A-55RC is pin-compatible with the JEDEC-standard AT27C256R in 28-pin SOIC (28R), PLCC (32J), and TSOP (28T) packages. For the AT27LV256A-55RC in SOIC, this means identical pin count, function mapping, and mechanical footprint-allowing direct substitution without PCB modifications, provided VPP is properly isolated during normal read operation.
What programming voltage and timing does the AT27LV256A-55RC require?
The AT27LV256A-55RC requires VCC = 6.5V ± 0.25V and VPP = 13.0V ± 0.25V during programming, with a CE pulse width of 95–105 µs. These values are specified in the DC and AC Programming Characteristics tables. A 0.1 µF ceramic capacitor must be placed between VPP and GND to suppress transients-failure to do so risks programming failure or device damage.
Does the AT27LV256A-55RC support product identification codes, and how are they accessed?
Yes, the AT27LV256A-55RC implements an integrated product identification code: Manufacturer ID = 0x1E and Device ID = 0x8C. These are accessed by setting A9 = 12.0V (VH), A0 = toggled, and all other address lines low (VIL) while CE and OE are asserted low-per the Product Identification section. This enables automatic algorithm selection in industry-standard programmers.
AT27LV256A-55RC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-SOIC (0.342", 8.69mm Width)
- 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:
- 55 ns
- Voltage - Supply:
- 3V ~ 3.6V, 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
AT27LV256A-55RC FAQ
1.How can I place an order for AT27LV256A-55RC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27LV256A-55RC 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 AT27LV256A-55RC reliable?
The price and inventory of AT27LV256A-55RC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27LV256A-55RC is usually 5 days.
3.What payment methods are accepted for AT27LV256A-55RC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27LV256A-55RC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27LV256A-55RC?
AT27LV256A-55RC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27LV256A-55RC 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 AT27LV256A-55RC?
For technical support, including AT27LV256A-55RC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27LV256A-55RC requirements.
6.How does Aetrix verify that AT27LV256A-55RC is sourced from the original manufacturer or authorized distributors?
All AT27LV256A-55RC 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 AT27LV256A-55RC meets industry standards.
7.What is the process for return or replacement of AT27LV256A-55RC?
All AT27LV256A-55RC units undergo pre-shipment inspection (PSI). If there is an issue with AT27LV256A-55RC, 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 AT27LV256A-55RC part is unused and in its original packaging.
Return procedure for AT27LV256A-55RC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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