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Microchip Technology AT27C020-55PC
- Part No.:
- AT27C020-55PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-DIP (0.600", 15.24mm)
- Datasheet:
-
AT27C020-55PC.pdf
- Description:
- IC EPROM 2MBIT PARALLEL 32DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,655
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Product details
Overview
AT27C020-55PC from Atmel is a 2-Mbit (256K × 8) one-time programmable EPROM with 55 ns read access time, 5V ±10% supply operation, and JEDEC-standard 32-lead PDIP package. It delivers TTL/CMOS-compatible I/O, rapid 100 µs/byte programming, and supports microprocessor systems requiring low-latency firmware storage without WAIT states.
For engineers reviewing the AT27C020-55PC datasheet, AT27C020-55PC pinout, AT27C020-55PC application, or AT27C020-55PC equivalent, key selection criteria include read timing (tACC = 55 ns), standby current (≤100 µA), OTP reliability for firmware boot code, and compatibility with legacy 5V EPROM-based designs using CE/OE dual-line control.
Technical Context
The AT27C020-55PC implements a standard OTP EPROM architecture with 18 address lines (A0–A17), 8 bidirectional data outputs (O0–O7), and dual enable control (CE and OE). Its Rapid™ Programming Algorithm uses 13.0 V VPP and 6.5 V VCC during programming, with strict sequencing requirements (VCC applied before/removed after VPP).
It features integrated product identification (Manufacturer ID = 0x1E, Device ID = 0x86) accessed via A9 high-voltage mode (11.5–12.5 V), and supports three temperature grades - commercial (0°C to 70°C), industrial (−40°C to 85°C), and automotive (−40°C to 125°C) - with the -55PC variant rated for commercial operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2,097,152 bits (256K × 8); stores full firmware images for 8-bit microcontrollers without external memory management. |
| Read Access Time | 55 ns max (tACC); enables direct interface with 12–16 MHz 8051, Z80, or 68K-family CPUs without wait-state insertion. |
| Supply Voltage | 5V ±10%; operates natively from standard logic rail, eliminating need for auxiliary voltage regulators in legacy systems. |
| Standby Current | 100 µA max (ISB1); ensures ultra-low power retention during system sleep modes in embedded controllers. |
| Programming Voltage | VPP = 13.0 V ±0.25 V; requires dedicated high-voltage programming circuitry - not compatible with standard 5V-only programmers. |
| ESD Protection | 2,000 V HBM; provides robust handling margin during manual PCB assembly and rework of legacy systems. |
| Latch-up Immunity | 200 mA; withstands transient overcurrent events common in noisy industrial power environments. |
Pinout & Package
AT27C020-55PC is supplied in a 32-lead, 0.600" wide plastic dual in-line package (PDIP), JEDEC MS-011 compliant. Pin 1 is marked by a notch or dot; package dimensions are 1.64" × 0.720" (41.7 mm × 18.3 mm).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address Inputs | 18-bit address bus interface; selects one of 256K bytes; A0 is LSB, A17 is MSB. |
| O0–O7 | Data Outputs | 8-bit bidirectional data bus; outputs valid within 55 ns of CE/OE assertion; high-impedance when disabled. |
| CE | Chip Enable | Active-low global chip select; must be stable before address setup to meet tCES ≥ 2 µs during programming. |
| OE | Output Enable | Active-low output gate; controls data bus float timing (tDF ≤ 18 ns); used with CE for bus contention avoidance. |
| PGM | Program Strobe | Active-low programming pulse input; accepts 95–105 µs width pulses at 13 V VPP for byte-level programming. |
| VPP | Programming Voltage | 13.0 V ±0.25 V input; must be sequenced after VCC and before PGM; requires 0.1 µF ceramic capacitor to ground. |
| VCC | Power Supply | +5V ±10% main supply; powers logic and outputs; supplies 25 mA max active current at 5 MHz. |
| GND | Ground | Reference return for all signals; requires local 0.1 µF ceramic decoupling per device per datasheet layout guidance. |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | 100 µs/byte typical programming time with auto-verify loop; reduces firmware update cycle time by >5× vs. legacy EPROMs. |
| Integrated Product Identification Code | Manufacturer ID (0x1E) and Device ID (0x86) readable via A9 high-voltage mode; enables automated programmer validation and BOM traceability. |
| Dual-Line Control (CE + OE) | Independent chip and output enables allow flexible bus arbitration in multi-device systems without additional logic gates. |
| 2,000V ESD / 200mA Latch-up Immunity | Meets industrial handling requirements; eliminates need for external protection components in field-deployed equipment. |
| Three Temperature Grades | Commercial (-55PC), Industrial (-55PI), and Automotive (-55PA) variants share identical pinout and timing - simplifies design reuse across platforms. |
Applications
| Industrial PLC Firmware Storage | Legacy Medical Device Boot ROM |
|---|---|
|
Use Scenario: Storing fixed boot code and safety-critical initialization routines in programmable logic controllers operating in factory-floor environments with wide temperature swings and EMI. IC Role / Device Role / Timing Role: Nonvolatile boot memory mapped to CPU address space; provides deterministic 55 ns read latency for real-time startup sequence execution. Use Value: Eliminates reliance on slower serial EEPROM or flash; ensures firmware integrity via OTP write-once guarantee and 200 mA latch-up immunity against power-rail transients. |
Use Scenario: Holding certified diagnostic firmware in Class II medical instruments where post-production code modification is prohibited by regulatory requirements. IC Role / Device Role / Timing Role: One-time programmable ROM providing immutable, tamper-evident firmware image; accessed during cold reset prior to RAM initialization. Use Value: Meets IEC 62304 software lifecycle requirements via hardware-enforced write-protection; 2,000 V ESD rating supports safe handling during ISO 13485-compliant manufacturing. |
| Military Communications Equipment | Automotive Engine Control Unit (ECU) |
|
Use Scenario: Storing cryptographic keys and secure boot loaders in tactical radios deployed in extreme ambient conditions (−55°C to +125°C). IC Role / Device Role / Timing Role: OTP EPROM serving as root-of-trust memory; interfaces directly with 8-bit microcontroller bus with no glue logic. Use Value: Supports MIL-STD-883 screening via automotive-grade variant (-55PA); 55 ns access enables fast secure boot verification without performance penalty. |
Use Scenario: Hosting calibration tables and engine map data in first-generation OBD-II ECUs where firmware updates occur only at dealership service centers. IC Role / Device Role / Timing Role: Read-only memory storing fuel injection timing and spark advance lookup tables; accessed synchronously with crankshaft position sensor interrupts. Use Value: Automotive temperature range (−40°C to +125°C) ensures reliability under hood conditions; OTP prevents unauthorized runtime modification of emission-critical parameters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT27C020-55JI | Same die, industrial temperature range (−40°C to +85°C); identical 55 ns timing and pinout. | Required for extended-temperature industrial control systems where ambient exceeds 70°C. | Select AT27C020-55JI when operating environment exceeds commercial grade limits but does not require full automotive qualification. |
| AM27C256B-55DC | 256K × 8 OTP EPROM from AMD; 55 ns access, 5V supply, but uses different programming algorithm and lacks integrated ID code. | Compatible in read-mode pinout and timing, but requires AMD-specific programmer support and lacks A9-based ID readback. | Choose AM27C256B-55DC only if existing production tooling is locked to AMD programming hardware and ID code is not required for traceability. |
Compared with AT27C020-55PC, the AT27C020-55JI offers identical functionality with extended thermal tolerance, while AM27C256B-55DC provides pin-compatible read operation but sacrifices programmable ID verification and requires alternate programming infrastructure.
Availability
AT27C020-55PC is available at Aetrix Electronics and suitable for industrial automation, legacy medical instrumentation, and military communications equipment requiring stable component supply and long-term obsolescence management.
Supply support for AT27C020-55PC 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
Atmel Corporation was a U.S.-based semiconductor company specializing in microcontrollers, nonvolatile memory, and security ICs, acquired by Microchip Technology in 2016.
The AT27C020 belongs to Atmel's 27C-series OTP EPROM family, designed specifically for reliable, low-power, pin-compatible replacement of UV-erasable EPROMs in cost-sensitive, high-reliability embedded systems.
FAQ
What is the maximum read access time specified for the AT27C020-55PC?
The AT27C020-55PC has a guaranteed maximum read access time (tACC) of 55 ns under commercial temperature conditions (0°C to 70°C) with VCC = 5V ±10%. This parameter is measured from address or CE/OE assertion to valid data output and defines the device's speed grade. The "-55" suffix explicitly denotes this 55 ns timing specification, making AT27C020-55PC suitable for high-speed 8-bit microprocessor buses without wait-state insertion.
Does the AT27C020-55PC support in-system programming?
No, the AT27C020-55PC does not support in-system programming. It requires external high-voltage (13.0 V ±0.25 V) programming via the VPP pin and dedicated EPROM programmer hardware. Programming must occur off-board under controlled lab conditions, as the device lacks serial interface, command protocols, or internal charge pumps needed for ISP. Once programmed, the AT27C020-55PC is permanently set - it is a true one-time programmable device.
What package type is used for the AT27C020-55PC?
The AT27C020-55PC uses a 32-lead, 0.600" wide plastic dual in-line package (PDIP), designated as package code 32P6 per Atmel's ordering information. This through-hole package complies with JEDEC MS-011 standards and features a standard 0.1" lead pitch. It is distinct from the PLCC (32J) and TSOP (32T) variants - the "PC" suffix in AT27C020-55PC explicitly identifies the PDIP configuration.
Can the AT27C020-55PC be used as a direct replacement for UV-erasable EPROMs like the 27C256?
Yes, the AT27C020-55PC is functionally and pin-compatible with 27C256-family EPROMs in read mode, sharing identical 32-pin DIP layout, 256K × 8 organization, and CE/OE dual-enable control. However, it differs critically in programming: AT27C020-55PC requires 13 V VPP and lacks UV erasure capability. System designers must ensure their programming infrastructure supports OTP high-voltage protocols and that firmware is finalized before programming - AT27C020-55PC cannot be reprogrammed or erased.
What is the purpose of the PGM pin on the AT27C020-55PC?
The PGM (Program Strobe) pin on the AT27C020-55PC is an active-low input used exclusively during programming to initiate each 100 µs byte-programming pulse. It must be asserted low while VPP = 13 V and VCC = 6.5 V, with precise timing (tPW = 95–105 µs). During normal read operation, PGM is held high (VIH) and has no effect. The AT27C020-55PC will not program unless PGM, VPP, and proper address/data are simultaneously valid - this prevents accidental writes.
AT27C020-55PC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-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:
- 2Mbit
- Memory Organization:
- 256K 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:
- 32-PDIP
AT27C020-55PC FAQ
1.How can I place an order for AT27C020-55PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C020-55PC 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 AT27C020-55PC reliable?
The price and inventory of AT27C020-55PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C020-55PC is usually 5 days.
3.What payment methods are accepted for AT27C020-55PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C020-55PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C020-55PC?
AT27C020-55PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C020-55PC 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 AT27C020-55PC?
For technical support, including AT27C020-55PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C020-55PC requirements.
6.How does Aetrix verify that AT27C020-55PC is sourced from the original manufacturer or authorized distributors?
All AT27C020-55PC 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 AT27C020-55PC meets industry standards.
7.What is the process for return or replacement of AT27C020-55PC?
All AT27C020-55PC units undergo pre-shipment inspection (PSI). If there is an issue with AT27C020-55PC, 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 AT27C020-55PC part is unused and in its original packaging.
Return procedure for AT27C020-55PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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