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Microchip Technology AT27C020-55JU-T
- Part No.:
- AT27C020-55JU-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT27C020-55JU-T.pdf
- Description:
- IC EPROM 2MBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
AT27C020-55JU-T 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 - deployed in industrial controllers and legacy embedded boot loaders.
For engineers reviewing the AT27C020-55JU-T datasheet, AT27C020-55JU-T pinout, AT27C020-55JU-T application, or AT27C020-55JU-T equivalent, key selection criteria include verified 55 ns tACC timing, rapid 100 µs/byte programming, VPP = 12.0 V ±0.5 V programming voltage, industrial temperature range (–40°C to +85°C), and integrated product identification code for automated programming equipment compatibility.
Technical Context
The AT27C020-55JU-T implements a parallel-addressed OTP EPROM architecture with dual-line control (CE/OE) enabling bus contention avoidance in shared-data-bus systems. Its internal logic supports five distinct operating modes - Read, Standby, Rapid Program, PGM Verify, and Product Identification - each defined by specific CE/OE/PGM voltage states and VPP conditions.
It uses high-reliability CMOS process technology with 2,000 V HBM ESD protection and 200 mA latchup immunity. Programming requires precise 100 µs ±5% PGM pulse width at VPP = 13.0 V ±0.25 V and VCC = 6.5 V ±0.25 V, followed by byte-by-byte verification with up to 10 reprogramming attempts per failed location.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256K × 8 bits (2,097,152-bit capacity); sufficient for full firmware images in 8-bit/16-bit microcontroller boot ROM applications |
| Read access time (tACC) | 55 ns max; eliminates WAIT states in 5 MHz Z80, 8086, and 68000-based systems |
| VCC supply | 5 V ±10%; single-supply operation compatible with legacy TTL/CMOS logic families without level translation |
| Standby current (ISB1) | 100 µA max (CMOS CE); enables low-power retention in always-on industrial control modules |
| Programming voltage (VPP) | 12.0 V ±0.5 V (ID mode), 13.0 V ±0.25 V (program mode); requires external high-voltage source or dedicated programmer |
| Operating temperature | –40°C to +85°C; qualified for industrial-grade deployment in factory automation and instrumentation |
| ESD/latchup rating | 2,000 V HBM ESD; 200 mA latchup immunity; ensures robustness in noisy factory-floor environments |
Pinout & Package
AT27C020-55JU-T is supplied in a 32-lead plastic J-leaded chip carrier (PLCC), JEDEC MS-016 Variation AE compliant, with 11.354–11.506 mm body width (D1), 13.894–14.046 mm body length (E1), and 1.270 mm lead pitch (e). Pin 1 identifier located at top-left corner with 45° chamfer.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address inputs | 18-bit address bus supporting full 256K-byte addressing; A0–A17 must be stable before CE/OE assertion |
| O0–O7 | Data outputs | 8-bit bidirectional data bus (output only); TTL/CMOS-compatible VOH ≥2.4 V, VOL ≤0.4 V at IOL = 2.1 mA |
| CE | Chip enable | Active-low global device select; controls entry into Read, Standby, or Program modes depending on OE/PGM state |
| OE | Output enable | Active-low output gate; enables O0–O7 drivers only when CE is also active; determines tOE (20 ns max) timing |
| PGM | Program strobe | Active-low programming trigger; initiates 100 µs pulse-driven byte programming when VPP = 13.0 V and CE = VIL |
| VPP | Programming voltage | 12.0–13.0 V input for ID and programming; must be applied simultaneously with or after VCC and removed simultaneously or before VCC |
| VCC | Power supply | 5 V ±10% main supply; powers core logic and outputs; ICC ≤25 mA at 5 MHz read frequency |
| GND | Ground reference | Signal and power return; requires local 0.1 µF ceramic decoupling capacitor placed within 5 mm of pins 16 and 32 |
Key Features
| Feature | Design Value |
|---|---|
| Rapid programming algorithm | 100 µs/byte typical programming time with automatic verify-and-reprogram loop; reduces production burn-in time by >70% vs. legacy EPROMs |
| Integrated product ID code | Two-byte electronic signature (0x1E manufacturer, 0x86 device) accessible via A9 = 12 V and A0 toggle; enables auto-algorithm selection in gang programmers |
| Two-line control interface | Independent CE and OE inputs allow flexible bus arbitration - CE disables internal logic, OE gates outputs - preventing contention during DMA or multi-master cycles |
| Green Pb/halide-free packaging | RoHS-compliant matte tin lead finish on 32J PLCC; meets IPC/JEDEC J-STD-609A Class 1 marking requirements |
| High-reliability process | 2,000 V HBM ESD protection and 200 mA latchup immunity validated per JEDEC JESD22-A114 and JESD78; suitable for unshielded industrial PCBs |
Applications
| Industrial PLC Firmware Storage | Legacy Microcontroller Boot ROM |
|---|---|
|
Use Scenario: Storing fixed ladder-logic firmware in modular programmable logic controllers where field updates are rare but long-term data retention is critical. IC Role / Device Role / Timing Role: Nonvolatile boot memory mapped to CPU address space; accessed during cold start and watchdog reset recovery. Use Value: 55 ns tACC ensures zero-wait-state execution from reset vector; 100 µA standby current minimizes power draw in battery-backed backup modules. |
Use Scenario: Providing immutable startup code for Z80, 8085, or 6809-based instrumentation systems deployed in oil/gas telemetry units. IC Role / Device Role / Timing Role: Primary ROM holding initialization routines, interrupt vectors, and hardware abstraction layer. Use Value: Industrial temperature rating (–40°C to +85°C) guarantees reliable boot across desert and arctic deployments; VPP-programmability allows factory-level firmware finalization. |
| Automotive ECU Calibration Memory | Medical Device Configuration Storage |
|
Use Scenario: Holding engine calibration tables and safety-critical lookup data in Tier-1 automotive ECUs where reprogramming is prohibited post-manufacture. IC Role / Device Role / Timing Role: One-time programmable configuration store; read-only during runtime to prevent corruption from EMI or software faults. Use Value: 2,000 V ESD rating withstands assembly-line handling; integrated ID code enables traceability and counterfeit detection in supply chain audits. |
Use Scenario: Storing FDA-mandated device-specific calibration constants and regulatory compliance flags in Class II medical infusion pumps. IC Role / Device Role / Timing Role: Immutable parameter repository accessed during power-up self-test and periodic diagnostic checks. Use Value: 256K-byte capacity accommodates multiple calibration profiles per device variant; RoHS-compliant green packaging satisfies IEC 60601-1 environmental requirements. |
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-bit, 70 ns access, PDIP package, no VPP pin (5 V-only programming) | Lacks rapid programming and product ID code; suited for cost-sensitive, non-gang-programmed designs | Select when board layout lacks VPP routing and programming throughput is secondary to unit cost |
| MX27C256A-12PC | 256K × 8-bit, 120 ns access, 5 V-only, 28-pin PDIP; no PGM pin or ID code | Slower timing and no high-voltage programming support; limited to legacy socket-based systems | Choose only for direct socket replacement in obsolete systems where 55 ns timing is not required |
Compared with AT27C256B-70PU and MX27C256A-12PC, the AT27C020-55JU-T delivers faster 55 ns access, integrated ID coding for automated programming, and robust 12 V VPP-driven rapid programming - making it the preferred choice for new industrial designs requiring production efficiency and traceability.
Availability
AT27C020-55JU-T is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, automotive ECU calibration memory, and medical device configuration storage requiring stable component supply over extended production lifecycles.
Supply support for AT27C020-55JU-T 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, aerospace, and automotive markets.
The AT27C020 series was designed as a high-reliability, one-time programmable EPROM for mission-critical firmware storage where data integrity, ESD robustness, and programming repeatability outweigh reprogrammability needs.
FAQ
What is the maximum allowed VPP voltage for programming the AT27C020-55JU-T?
The AT27C020-55JU-T requires VPP = 13.0 V ±0.25 V during rapid programming and VPP = 12.0 V ±0.5 V for product identification mode. Exceeding 13.25 V risks permanent damage per Absolute Maximum Ratings; the device specifies –2.0 V to +14.0 V as absolute limit on A9 and VPP pins, but functional programming is strictly bounded by the 13.0 V ±0.25 V specification. Always apply VPP simultaneously with or after VCC and remove it simultaneously or before VCC.
Does the AT27C020-55JU-T support in-system programming?
No, the AT27C020-55JU-T does not support in-system programming. It requires a dedicated EPROM programmer capable of delivering 12–13 V to the VPP pin and generating precise 100 µs ±5% PGM pulses. The device lacks serial interfaces, command protocols, or internal charge pumps needed for ISP; programming must occur in a socketed or ZIF-socket environment with full VPP and PGM signal access.
What decoupling capacitors are required for stable operation of the AT27C020-55JU-T?
The AT27C020-55JU-T requires two decoupling capacitors: a 0.1 µF high-frequency ceramic capacitor placed between VCC and GND as close as possible to pins 16 and 32, and a 4.7 µF bulk electrolytic capacitor near the power entry point of any EPROM array. These mitigate transient voltage excursions during CE switching and stabilize VCC under rapid output switching loads, preventing nonconformance per system considerations in the datasheet.
How is the product identification code read from the AT27C020-55JU-T?
The product identification code of the AT27C020-55JU-T is read by setting A9 = 12.0 V ±0.5 V (VID), holding A1–A17 = VIL, and toggling A0: A0 = VIL reads the manufacturer ID byte (0x1E), A0 = VIH reads the device ID byte (0x86). This mode requires CE = OE = VIL and VPP = VID; outputs O0–O7 reflect the selected byte. Standard 5 V read mode cannot access this code.
Is the AT27C020-55JU-T pin-compatible with the AT27C020-55PU?
Yes, the AT27C020-55JU-T and AT27C020-55PU share identical pin functions and electrical characteristics, but differ in package: JU denotes 32-lead PLCC (32J), PU denotes 32-lead PDIP (32P6). Their pinouts are functionally identical (A0–A17, O0–O7, CE, OE, PGM, VPP, VCC, GND), though physical layout and mounting differ. No PCB redesign is needed when substituting between packages if mechanical constraints allow.
AT27C020-55JU-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (13.97x11.43)
AT27C020-55JU-T FAQ
1.How can I place an order for AT27C020-55JU-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C020-55JU-T 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-T reliable?
The price and inventory of AT27C020-55JU-T 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-T is usually 5 days.
3.What payment methods are accepted for AT27C020-55JU-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C020-55JU-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C020-55JU-T?
AT27C020-55JU-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C020-55JU-T 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-T?
For technical support, including AT27C020-55JU-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C020-55JU-T requirements.
6.How does Aetrix verify that AT27C020-55JU-T is sourced from the original manufacturer or authorized distributors?
All AT27C020-55JU-T 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-T meets industry standards.
7.What is the process for return or replacement of AT27C020-55JU-T?
All AT27C020-55JU-T units undergo pre-shipment inspection (PSI). If there is an issue with AT27C020-55JU-T, 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-T part is unused and in its original packaging.
Return procedure for AT27C020-55JU-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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