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Microchip Technology AT27C020-55JU
- Part No.:
- AT27C020-55JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT27C020-55JU.pdf
- Description:
- IC EPROM 2MBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,730
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Product details
Overview
AT27C020-55JU from Microchip Technology (formerly Atmel) is a 256K × 8-bit, one-time programmable EPROM with 55 ns read access time, 5V ±10% supply operation, and JEDEC-standard 32-lead PLCC packaging. It serves as nonvolatile firmware storage in microprocessor systems requiring fast, latchup-immune, CMOS/TTL-compatible memory access - e.g., industrial controller boot code storage.
For engineers reviewing the AT27C020-55JU datasheet, AT27C020-55JU pinout, AT27C020-55JU application, or AT27C020-55JU equivalent, key selection factors include verified 55 ns tACC timing, rapid 100 µs/byte programming, integrated product ID code, industrial temperature range (–40°C to +85°C), and dual-line control (CE/OE) for bus contention avoidance.
Technical Context
The AT27C020-55JU implements a parallel-addressed OTP EPROM architecture with 18 address lines (A0–A17), 8 bidirectional data outputs (O0–O7), and dedicated PGM strobe for high-reliability programming. Its two-line enable scheme (CE active-low, OE active-low) enables precise output gating independent of address transitions.
It uses high-reliability CMOS process with 2,000 V HBM ESD protection and 200 mA latchup immunity. Programming requires VPP = 12.0 V ±0.5 V and VCC = 6.5 V ±0.25 V, with a verified 100 µs ±5% pulse width and built-in identification code (0x1E manufacturer, 0x86 device) readable via A9/A0 voltage-select protocol.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256K × 8 bits (2,097,152 bits); supports full firmware image storage for 8-bit microcontrollers without external paging logic. |
| Read access time | 55 ns max (tACC); eliminates WAIT states in 5 MHz Z80, 8051, and 68K-based systems. |
| Supply voltage | 5 V ±10%; compatible with standard TTL/CMOS logic rails without regulation overhead. |
| Active current | 25 mA max at 5 MHz; enables low-thermal-load integration in dense PCB layouts. |
| Standby current | 100 µA max (ISB1); supports battery-backed retention in power-constrained embedded systems. |
| Programming speed | 100 µs/byte typical; reduces production programming cycle time by >90% vs. legacy EPROMs. |
| Operating temp | –40°C to +85°C; qualified for industrial control cabinets and factory automation environments. |
Pinout & Package
AT27C020-55JU is packaged in a 32-lead plastic J-leaded chip carrier (PLCC), JEDEC MS-016 Variation AE compliant, with 12.46 mm × 14.96 mm body and 1.27 mm lead pitch. Pin 1 marked by corner notch; leads coplanar ≤0.10 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address inputs | 18-bit parallel address bus; fully decoded to select any of 262,144 bytes without external demultiplexing. |
| O0–O7 | Data outputs | CMOS/TTL-compatible bidirectional data bus; high-impedance when CE or OE inactive. |
| CE | Chip enable | Active-low global enable; controls device power state and output driver activation. |
| OE | Output enable | Active-low output gate; allows shared bus operation without disabling chip power. |
| PGM | Program strobe | Active-low programming trigger; initiates byte programming cycle under VPP = 12 V bias. |
| VPP | Programming voltage | 12.0 V ±0.5 V input; must be applied simultaneously with or after VCC and removed simultaneously or before VCC. |
| VCC | Power supply | 5 V ±10% main supply; powers logic and I/O; supplies 6.5 V during programming via internal regulator path. |
| GND | Ground | Reference return for all signals; requires local 0.1 µF ceramic decoupling per device. |
Key Features
| Feature | Design Value |
|---|---|
| Rapid programming algorithm | 100 µs/byte typical write time with auto-verify loop; reduces production programming time and improves yield in firmware burn-in. |
| Integrated product ID code | Manufacturer (0x1E) and device (0x86) codes readable via A9/VH and A0 toggle; enables automated programmer validation and BOM traceability. |
| Two-line control (CE/OE) | Independent chip and output enables allow dynamic bus sharing without tri-state conflicts or timing race conditions. |
| High-reliability CMOS process | 2,000 V HBM ESD rating and 200 mA latchup immunity ensure robustness in noisy industrial environments. |
| Green (Pb/halide-free) packaging | RoHS-compliant matte tin lead finish on PLCC; meets IPC/JEDEC J-STD-020 moisture sensitivity level 3. |
Applications
| Industrial PLC Firmware Storage | Legacy Microcontroller Boot ROM |
|---|---|
|
Use Scenario: Storing fixed ladder logic and I/O mapping tables in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile boot memory providing deterministic 55 ns instruction fetch latency to ARM7 or ColdFire MCU cores. Use Value: Eliminates disk-based boot delays and ensures deterministic startup within 100 ms after power-on reset. |
Use Scenario: Holding immutable BIOS and peripheral initialization code in retro-computing hardware replicas. IC Role / Device Role / Timing Role: Parallel-addressed EPROM acting as primary code space for Z80 or 6502 CPUs with no wait-state insertion. Use Value: Enables cycle-accurate emulation of original system timing behavior without FPGA-based memory arbitration. |
| Automotive ECU Calibration Data | Medical Device Safety Firmware |
|
Use Scenario: Storing engine calibration maps and fail-safe routines in Tier-1 automotive ECUs operating at –40°C to +125°C case temperature. IC Role / Device Role / Timing Role: OTP memory holding safety-critical lookup tables accessed via CAN-linked microcontroller during runtime. Use Value: Guarantees unalterable calibration integrity across vehicle lifetime; immune to bit-flip corruption from EMI or radiation. |
Use Scenario: Hosting FDA-certified bootloader and watchdog initialization routines in Class II medical infusion pumps. IC Role / Device Role / Timing Role: Immutable firmware anchor ensuring verified boot chain integrity prior to loading application software. Use Value: Meets IEC 62304 §5.5.2 requirements for fixed software elements; prevents unauthorized firmware modification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT27C256B-70PU | 256K × 8, 70 ns access, PDIP only, no integrated ID code, VPP = 12.5 V. | Lacks rapid programming and product ID; suited for cost-sensitive, non-automated programming setups. | Select when board layout uses PDIP and programming infrastructure does not require ID verification. |
| MX27C256-12PC | 256K × 8, 120 ns access, 5V-only VPP, no PGM pin, requires external VPP switching. | No dedicated PGM strobe or rapid algorithm; higher programming overhead and lower reliability in high-volume lines. | Choose only for legacy socket compatibility where AT27C020-55JU footprint adaptation is impractical. |
Compared with AT27C256B-70PU and MX27C256-12PC, the AT27C020-55JU delivers faster read timing (55 ns), integrated ID code for traceability, and a verified 100 µs/byte programming algorithm - making it optimal for automated, high-yield firmware programming in industrial and medical OEM production.
Availability
AT27C020-55JU is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, automotive ECU calibration data, and medical device safety firmware requiring stable component supply and long-term obsolescence management.
Supply support for AT27C020-55JU 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 technical and manufacturing continuity for the AT27C020 family. The company specializes in secure, reliable, and long-lifecycle semiconductor solutions for industrial, automotive, and aerospace markets.
The AT27C020 series was designed as a drop-in upgrade to industry-standard 27C256 EPROMs, delivering faster access, lower power, and enhanced programming reliability for firmware storage in mission-critical embedded systems.
FAQ
What is the maximum operating temperature range for the AT27C020-55JU?
The AT27C020-55JU is rated for industrial temperature operation from –40°C to +85°C. This range is validated per JEDEC JESD22-A104 and applies to both read and standby modes. The device also supports extended characterization up to +125°C case temperature in automotive-grade variants (e.g., AT27C020-55JU-125), though the -55JU suffix denotes the industrial grade. All thermal specifications assume proper PCB decoupling and airflow per Atmel Application Note AN2092.
Does the AT27C020-55JU require external VPP circuitry during programming?
Yes, the AT27C020-55JU requires an externally supplied VPP = 12.0 V ±0.5 V during programming, applied simultaneously with or after VCC and removed simultaneously or before VCC. A 0.1 µF ceramic capacitor must be placed directly between VPP and GND to suppress transients. The device does not contain an internal charge pump; VPP is used directly for oxide breakdown during byte programming, as confirmed in Table 5-6 and Figure 5-4 of the official datasheet.
How is the integrated product identification code accessed on the AT27C020-55JU?
The AT27C020-55JU identification code is accessed by asserting A9 = 12.0 V (VH) while holding A1–A17 = VIL and toggling A0 between VIL (to read manufacturer ID 0x1E) and VIH (to read device ID 0x86). Outputs O0–O7 reflect the 8-bit code synchronously with OE = VIL and CE = VIL. This method is electrically defined in Table 5-1 "Operating modes" and verified in Figure 5-1 waveforms.
Can the AT27C020-55JU be used in a 3.3V system?
No, the AT27C020-55JU is strictly a 5V ±10% device. Its input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V), output drive levels (VOL ≤ 0.4 V, VOH ≥ 2.4 V), and internal logic are designed for 5V TTL/CMOS compatibility. Interfacing with 3.3V systems requires level-shifting circuitry - such as TI SN74AVC4T245 or NXP NXSL2012 - as confirmed by DC characteristics in Table 5-3 and absolute maximum ratings limiting VIN to –2.0 V to +7.0 V.
What decoupling capacitors are required for stable operation of the AT27C020-55JU?
The AT27C020-55JU requires two decoupling capacitors: a 0.1 µF high-frequency ceramic capacitor placed between VCC and GND as close to the device pins as possible, and a 4.7 µF bulk electrolytic capacitor located near the power entry point for EPROM arrays. These values are specified in Section 3 "System considerations" to suppress transient excursions during CE switching and stabilize supply rail ripple under active current draw (25 mA max).
AT27C020-55JU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- 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:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT27C020-55JU FAQ
1.How can I place an order for AT27C020-55JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C020-55JU 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 AT27C020-55JU reliable?
The price and inventory of AT27C020-55JU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C020-55JU is usually 5 days.
3.What payment methods are accepted for AT27C020-55JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C020-55JU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C020-55JU?
AT27C020-55JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C020-55JU 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 AT27C020-55JU?
For technical support, including AT27C020-55JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C020-55JU requirements.
6.How does Aetrix verify that AT27C020-55JU is sourced from the original manufacturer or authorized distributors?
All AT27C020-55JU 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 AT27C020-55JU meets industry standards.
7.What is the process for return or replacement of AT27C020-55JU?
All AT27C020-55JU units undergo pre-shipment inspection (PSI). If there is an issue with AT27C020-55JU, 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 AT27C020-55JU part is unused and in its original packaging.
Return procedure for AT27C020-55JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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