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Microchip Technology AT27C512R-55PC
- Part No.:
- AT27C512R-55PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AT27C512R-55PC.pdf
- Description:
- IC EPROM 512KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,019
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Product details
Overview
AT27C512R-55PC from Microchip Technology (formerly Atmel) is a 512 Kbit (64K × 8) one-time programmable EPROM designed for nonvolatile firmware storage in embedded microprocessor systems. It delivers 45 ns read access time, operates from a single 5V ±10% supply, and supports commercial temperature range (0°C to 70°C) in a 28-lead 600-mil PDIP package - enabling direct replacement of mask ROM or UV-EPROM without WAIT-state insertion.
For engineers reviewing the AT27C512R-55PC datasheet, AT27C512R-55PC pinout, AT27C512R-55PC application, or AT27C512R-55PC equivalent, key selection criteria include verified 45 ns tACC timing at 5 MHz, CMOS/TTL I/O compatibility, Rapid™ programming algorithm (100 µs/byte), integrated product identification code, and JEDEC-standard 28P6 PDIP mechanical footprint compliance.
Technical Context
The AT27C512R-55PC implements a two-line control architecture with Chip Enable (CE) and Output Enable/VPP pins, allowing flexible bus contention management in multi-device memory maps. Its internal address decoder accepts A0–A15 inputs to select one of 65,536 bytes, while O0–O7 provide TTL/CMOS-compatible bidirectional data outputs during read mode.
During programming, OE/VPP serves as the 12.0 V ±0.5 V programming voltage input, and CE pulses (95–105 µs width) trigger byte-wise programming under Rapid™ algorithm control. The device integrates manufacturer and device identification codes accessible via A9 high-voltage (11.5–12.5 V) and A0 toggling, enabling automated programmer recognition.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 524,288 bits (64K × 8) - supports full 16-bit address space for 8-bit microcontrollers without banking. |
| Read Access Time (tACC) | 55 ns max - guarantees sub-18.2 MHz bus operation without wait states on 8051, Z80, or 68K-based systems. |
| Supply Voltage | 5.0 V ±10% - eliminates need for auxiliary voltage rails; compatible with standard logic-level power domains. |
| Active Current (ICC) | 20 mA max at 5 MHz - enables low-power system design when active; typical 8 mA reduces thermal load. |
| Standby Current (ISB) | 100 µA max - allows battery-backed retention in sleep modes without significant drain. |
| Programming Speed | 100 µs/byte typical - cuts firmware update time by >90% vs. legacy EPROMs; verified per Rapid™ algorithm. |
| ESD Protection | 2,000 V HBM - meets industrial handling requirements without external protection circuitry. |
| Latchup Immunity | 200 mA - withstands transient overcurrent events common in noisy industrial environments. |
Pinout & Package
AT27C512R-55PC is housed in a 28-lead, 0.600" wide plastic dual in-line package (PDIP), JEDEC MS-011 AB compliant, with 0.300" row spacing and 0.100" lead pitch. Pin 1 is marked by notch or dot; leads are tin-lead plated for solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A15 | Address Inputs | 16-bit parallel address bus interface; fully decoded internally to select one of 65,536 bytes. |
| O0–O7 | Data Outputs | 8-bit bidirectional TTL/CMOS-compatible data bus; high-impedance when CE or OE/VPP inactive. |
| CE | Chip Enable | Primary chip-select; device enters standby (100 µA) when high; enables read or program when low. |
| OE/VPP | Output Enable / Programming Voltage | Read mode: output enable control; Program mode: 12.0 V ±0.5 V programming supply input. |
| GND | Ground Reference | Signal and power return; requires local 0.1 µF ceramic decoupling per device per datasheet Section 3. |
| VCC | Power Supply | +5.0 V ±10% main supply; must be applied simultaneously with or before OE/VPP during programming. |
| NC | No Connect | Not internally bonded; must remain unconnected to avoid parasitic coupling or latchup risk. |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | 100 µs/byte typical programming time with built-in verification loop - reduces production programming cycle time and improves yield. |
| Integrated Product Identification Code | Manufacturer ID (0x1E) and Device Code (0x0D) readable via A9=12 V and A0 toggle - enables automatic algorithm selection in production programmers. |
| Two-Line Control Architecture | Independent CE and OE/VPP pins - allows flexible memory mapping and eliminates bus contention during partial decoding. |
| High-Reliability CMOS Process | 2,000 V ESD rating and 200 mA latchup immunity - ensures robustness in manufacturing, test, and field deployment environments. |
| JEDEC-Standard Packaging Options | 28P6 PDIP, 28R SOIC, 28T TSOP, and 32J PLCC footprints - supports drop-in replacement across board generations and form factors. |
Applications
| Industrial PLC Firmware Storage | Automotive Instrument Cluster Boot Code |
|---|---|
Use Scenario: Storing fixed boot firmware and calibration tables in programmable logic controllers where field updates are rare but long-term data retention is critical. IC Role / Device Role / Timing Role: Nonvolatile program memory providing deterministic 55 ns read latency to ensure real-time scan-cycle execution. Use Value: Eliminates need for external wait-state generators; 100 µA standby current extends backup battery life beyond 10 years in maintenance-free deployments. |
Use Scenario: Holding safety-critical startup code and gauge initialization routines in automotive digital instrument clusters operating across -40°C to +85°C. IC Role / Device Role / Timing Role: OTP EPROM serving as primary boot ROM, interfacing directly with 8-bit microcontroller address/data buses. Use Value: 200 mA latchup immunity prevents system failure during load-dump transients; 5V-only operation simplifies power architecture. |
| Legacy System ROM Replacement | Medical Device Configuration Memory |
Use Scenario: Replacing obsolete 27C512 UV-EPROMs in aging test equipment and telecom line cards where UV erasers are no longer available or practical. IC Role / Device Role / Timing Role: Pin-compatible OTP substitute with identical 28-pin PDIP footprint and AC timing behavior. Use Value: Enables continued production without PCB redesign; Rapid™ programming supports fast rework and small-batch firmware revisions. |
Use Scenario: Storing FDA-required device configuration parameters and calibration constants in Class II medical monitors with zero-field-update requirement. IC Role / Device Role / Timing Role: Immutable configuration store accessed during power-on self-test (POST) prior to runtime software execution. Use Value: One-time programmability prevents accidental or malicious modification; 2,000 V ESD protection ensures reliability during clinical handling and sterilization cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM27C512-55DC | 55 ns access, 28-pin PDIP, 5V-only, but lacks Integrated Product ID Code and Rapid™ programming support. | Requires manual algorithm selection in programmers; no A9-based ID readback capability. | Choose when cost sensitivity outweighs programming automation needs and legacy toolchains are already established. |
| MX27C512-55PC | 55 ns access, same 28P6 package, but rated only for commercial temp (0°C–70°C) and specifies 25 mA active current (vs. 20 mA max for AT27C512R-55PC). | Higher active power draw may impact thermal budget in dense memory arrays; no automotive-grade variant available. | Prefer for cost-driven consumer applications where 5 mA higher ICC and absence of automotive qualification are acceptable. |
Compared with AM27C512-55DC and MX27C512-55PC, the AT27C512R-55PC provides superior programming automation via its Integrated Product Identification Code and tighter active current spec (20 mA max), making it optimal for high-reliability industrial and automotive firmware storage where programming repeatability and thermal margin matter.
Availability
AT27C512R-55PC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, automotive instrument cluster boot code, and legacy system ROM replacement requiring stable component supply, long-lifecycle availability, and JEDEC-standard 28P6 PDIP compatibility.
Supply support for AT27C512R-55PC 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 the legacy AT27C512R family, including datasheets, programming specifications, and long-term supply commitments.
The AT27C512R product line was engineered for reliable, low-power, one-time programmable firmware storage in resource-constrained embedded systems - emphasizing deterministic timing, industrial-grade robustness, and seamless integration into existing 8-bit microcontroller memory maps.
FAQ
What is the maximum operating frequency supported by the AT27C512R-55PC?
The AT27C512R-55PC supports up to 18.2 MHz bus operation without wait states, derived from its 55 ns maximum address-to-output delay (tACC). At 5 MHz clock frequency, active current remains within 20 mA limit, and timing margins comply fully with AC characteristics in the official Microchip datasheet Rev. 0015I–07/98. This makes AT27C512R-55PC suitable for 8051, Z80, and 68000-based designs requiring deterministic memory access.
Does the AT27C512R-55PC require a 12 V supply for normal read operation?
No, the AT27C512R-55PC requires only a single 5.0 V ±10% supply for read operation. The 12 V input (applied to OE/VPP) is used exclusively during programming - not during read mode. In read mode, OE/VPP functions as a standard TTL/CMOS-compatible output enable signal pulled to VIL (≤0.8 V) to activate outputs. Applying 12 V during read will damage the AT27C512R-55PC.
Can the AT27C512R-55PC be programmed in-system?
The AT27C512R-55PC is not designed for in-system programming. It requires external EPROM programmers capable of delivering precise 12.0 V ±0.5 V to OE/VPP and controlled 100 µs CE pulses per byte, along with proper VCC sequencing (6.5 V during programming, then 5.0 V for verification). Its OTP nature and lack of serial interface or command protocol preclude ISP; programming occurs off-board prior to soldering. This applies specifically to the AT27C512R-55PC in PDIP packaging.
What is the purpose of the NC pin on the AT27C512R-55PC?
The NC (No Connect) pin on the AT27C512R-55PC - Pin 27 in the 28P6 PDIP package - is not internally bonded and serves no electrical function. It must remain unconnected on the PCB to prevent unintended coupling, noise injection, or potential latchup paths. Unlike some variants, the AT27C512R-55PC does not repurpose NC as a test or configuration pin; leaving it floating or tied to ground/VCC violates the AT27C512R-55PC datasheet and risks functional instability.
How does the Integrated Product Identification Code work in the AT27C512R-55PC?
The AT27C512R-55PC embeds two identification bytes: Manufacturer ID (0x1E) and Device Code (0x0D), accessible by setting A9 to 11.5–12.5 V while holding A1–A15 low and toggling A0. When A0 = VIL, the Manufacturer ID appears on O7–O0; when A0 = VIH, the Device Code appears. This feature enables industry-standard programmers to auto-detect the AT27C512R-55PC and select correct voltage profiles and algorithms - a capability absent in most competing OTP EPROMs.
AT27C512R-55PC 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:
- 512Kbit
- Memory Organization:
- 64K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- -
- Access Time:
- 55 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-PDIP
AT27C512R-55PC FAQ
1.How can I place an order for AT27C512R-55PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C512R-55PC 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 AT27C512R-55PC reliable?
The price and inventory of AT27C512R-55PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C512R-55PC is usually 5 days.
3.What payment methods are accepted for AT27C512R-55PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C512R-55PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C512R-55PC?
AT27C512R-55PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C512R-55PC 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 AT27C512R-55PC?
For technical support, including AT27C512R-55PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C512R-55PC requirements.
6.How does Aetrix verify that AT27C512R-55PC is sourced from the original manufacturer or authorized distributors?
All AT27C512R-55PC 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 AT27C512R-55PC meets industry standards.
7.What is the process for return or replacement of AT27C512R-55PC?
All AT27C512R-55PC units undergo pre-shipment inspection (PSI). If there is an issue with AT27C512R-55PC, 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 AT27C512R-55PC part is unused and in its original packaging.
Return procedure for AT27C512R-55PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT27C512R-55PC 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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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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AT24C08C-STUM-T
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