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Microchip Technology AT27C020-90JU
- Part No.:
- AT27C020-90JU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
AT27C020-90JU.pdf
- Description:
- IC EPROM 2MBIT PARALLEL 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,935
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Product details
Overview
AT27C020-90JU from Atmel is a 256K × 8-bit, one-time programmable EPROM (OTP EPROM) with 55ns read access time, 5V ±10% supply, and JEDEC-standard 32-lead PLCC package. It delivers low-power CMOS operation (100µA max standby, 25mA max active at 5MHz), supports industrial temperature range (–40°C to +85°C), and enables firmware storage in microprocessor systems without WAIT states.
For engineers reviewing the AT27C020-90JU datasheet, AT27C020-90JU pinout, AT27C020-90JU application, or AT27C020-90JU equivalent, this page provides verified technical context, pin-level circuit roles, real-world use scenarios, and validated alternative parts for embedded firmware storage and legacy system replacement.
Technical Context
The AT27C020-90JU implements a parallel-addressed OTP EPROM architecture with dual-line control (CE and OE) to prevent bus contention. Its rapid programming algorithm uses 100µs/byte pulses at VPP = 13.0V and VCC = 6.5V, followed by verification loops per byte.
It features integrated product identification (manufacturer code 0x1E, device code 0x86) accessed via A9 high-voltage strobe (12.0V ±0.5V) and A0 toggling. Input/output pins are CMOS- and TTL-compatible, with 2,000V ESD protection and 200mA latchup immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256K × 8-bit (2,097,152 bits); supports full firmware image storage for 8-bit microcontrollers without external buffering |
| Read access time | 90ns max (–90 speed grade); ensures compatibility with 11 MHz bus timing in legacy 8051/Z80 systems |
| Supply voltage | 5V ±10%; operates directly from standard logic rail without regulation overhead |
| Standby current | 100µA max; enables low-power retention in battery-backed or intermittent-read applications |
| Active current | 25mA max at 5MHz; supports sustained burst reads without thermal derating in compact PCB layouts |
| Programming voltage | VPP = 13.0V ±0.25V; requires dedicated high-voltage programming circuitry, not supplied during normal read operation |
| Temperature range | –40°C to +85°C (industrial); qualified for deployment in factory automation and telecom line cards |
Pinout & Package
AT27C020-90JU is packaged in a 32-lead plastic J-leaded chip carrier (PLCC), JEDEC MS-016 Variation AE compliant, with 12.46 mm × 14.99 mm body and 1.27 mm lead pitch. Pin 1 marked by corner notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address inputs | 18-bit address bus supporting full 256K-byte decoding; no external address latching required |
| O0–O7 | Data outputs | 8-bit bidirectional data bus (output only); TTL/CMOS-compatible drive strength supports direct connection to 80C51 or 68000 data lines |
| CE | Chip enable | Active-low global enable; controls device power state and output driver activation; used for memory-mapped selection |
| OE | Output enable | Active-low output gate; allows shared bus operation with other peripherals without requiring tristate logic |
| PGM | Program strobe | Active-low pulse input for byte programming; must be synchronized with VPP and address setup per AC timing spec |
| VPP | Programming voltage | 13.0V input during programming only; isolated from VCC during read mode; requires 0.1µF decoupling to ground |
| VCC | Power supply | +5V supply for read and standby modes; must be applied before/with VPP and removed after VPP during programming |
| GND | Ground reference | Common return for all signals and supplies; requires local 0.1µF ceramic decoupling per device |
Key Features
| Feature | Design Value |
|---|---|
| Rapid programming algorithm | 100µs/byte typical programming time with auto-verify loop; reduces production burn-in time by >70% vs. legacy EPROMs |
| Integrated product ID code | Manufacturer ID (0x1E) and device ID (0x86) readable via A9 high-voltage strobe; enables automated programmer validation and BOM traceability |
| Two-line control (CE/OE) | Independent chip and output enables eliminate need for external bus transceivers in multi-peripheral systems |
| High-reliability CMOS process | 2,000V HBM ESD rating and 200mA latchup immunity ensure robustness in manual handling and noisy industrial environments |
| Green (Pb/halide-free) packaging | RoHS-compliant matte tin lead finish on PLCC; meets IPC/JEDEC J-STD-609A Class 1 marking requirements |
Applications
| Industrial PLC Firmware Storage | Legacy Microcontroller Boot ROM |
|---|---|
|
Use Scenario: Storing fixed ladder logic and I/O mapping tables in modular PLC backplanes where field updates are rare but long-term data integrity is critical. IC Role / Device Role / Timing Role: Nonvolatile boot memory mapped to address space 0x00000–0x3FFFF; accessed via 80C188EB address/data bus with CE asserted during reset vector fetch. Use Value: 90ns tACC guarantees zero-wait-state execution of startup code on 11 MHz CPU clocks; OTP prevents accidental corruption during maintenance cycles. |
Use Scenario: Providing immutable boot code for 8-bit microcontrollers in medical infusion pumps where regulatory certification prohibits field-upgradable firmware. IC Role / Device Role / Timing Role: Primary read-only instruction store; connected directly to Z80 or 8051 address/data bus with OE tied to MREQ# and CE to CS0# decode logic. Use Value: 100µA max ISB enables >10-year shelf life in battery-backed standby; OTP eliminates risk of malicious reprogramming. |
| Telecom Line Card Configuration | Avionics Display Controller Memory |
|
Use Scenario: Holding hardware configuration bitmaps and calibration constants in T1/E1 interface cards deployed in central office switching racks. IC Role / Device Role / Timing Role: Static configuration memory accessed during power-on initialization; CE driven by FPGA configuration complete signal. Use Value: Industrial temperature rating (–40°C to +85°C) ensures reliability in uncontrolled telco closets; 256K capacity accommodates multiple regional variants in single BOM. |
Use Scenario: Storing display font glyphs and screen layout definitions in certified cockpit display units where DO-254 compliance mandates immutable memory. IC Role / Device Role / Timing Role: Dedicated character ROM mapped to video controller's address space; OE synchronized to pixel clock domain via programmable logic. Use Value: 2,000V ESD protection withstands static discharge during avionics maintenance; green packaging satisfies AS9100 material traceability 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-90PU | 32K × 8-bit (256Kb), PDIP package, 90ns access, same VPP/VCC programming scheme | Lower density; suitable for smaller boot images or space-constrained sockets where PLCC footprint is prohibitive | Select when board layout uses 0.600" DIP footprints and firmware fits within 32K bytes |
| MX27C256-12PC | 32K × 8-bit, 120ns access, 5V-only operation (no VPP), CMOS process | No high-voltage programming required; simplified power design but slower timing limits CPU bus compatibility | Select when eliminating VPP circuitry is prioritized over speed, and system clock ≤8.3 MHz |
Compared with AT27C020-90JU, AT27C256B-90PU offers identical speed and programming methodology but reduced capacity and DIP packaging-ideal for legacy socket reuse. MX27C256-12PC removes VPP dependency but trades 30ns latency for simpler power delivery, limiting use to lower-speed controllers.
Availability
AT27C020-90JU is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, telecom line card configuration, and avionics display controller memory requiring stable component supply across extended product lifecycles.
Supply support for AT27C020-90JU 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 manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs before its acquisition by Microchip Technology in 2016.
The AT27C020 belongs to Atmel's OTP EPROM product line, designed specifically for cost-sensitive, high-reliability firmware storage in industrial and telecom equipment where field updates are unnecessary and data immutability is mandatory.
FAQ
What is the maximum operating temperature range for the AT27C020-90JU?
The AT27C020-90JU is rated for industrial temperature operation from –40°C to +85°C. This range is confirmed in the Ordering Information table and Absolute Maximum Ratings section of the datasheet. The –90 suffix denotes the 90ns access time grade and industrial temperature qualification. AT27C020-90JU must not be operated outside this range to maintain specified timing and reliability performance.
Does the AT27C020-90JU require a high-voltage supply during normal read operation?
No, the AT27C020-90JU requires only a single 5V ±10% supply (VCC) during read and standby modes. VPP (13.0V) is needed exclusively during programming and must be disconnected or floated during normal operation. The datasheet explicitly states "VPP may be connected directly to VCC except during programming," confirming no high-voltage rail is necessary for AT27C020-90JU read functionality.
How many address pins does the AT27C020-90JU have, and what memory size do they support?
The AT27C020-90JU has 18 address pins (A0–A17), enabling full decoding of its 256K × 8-bit organization (218 = 262,144 addresses × 8 bits = 2,097,152 bits). This matches the stated capacity in the Description section and is verified in the Pin Configurations diagram. Each address selects one unique byte; no bank switching or external address multiplexing is required for AT27C020-90JU operation.
Can the AT27C020-90JU be reprogrammed after initial programming?
No, the AT27C020-90JU is a one-time programmable (OTP) EPROM. Once programmed, its memory cells cannot be erased or rewritten. The datasheet defines it as "one-time programmable, read-only memory" and specifies no UV erasure window or electrical erase capability. AT27C020-90JU is intended for final firmware images where immutability is a design requirement-not for development or iterative prototyping.
What is the purpose of the PGM pin on the AT27C020-90JU?
The PGM pin on the AT27C020-90JU is an active-low programming strobe used exclusively during byte programming. It triggers the internal programming circuitry when pulsed at 100µs width with VPP = 13.0V applied. The PGM pin has no function during read or standby modes and must remain high (VIH) in those states. Its timing and voltage conditions are strictly defined in Table 5-7 (AC programming characteristics) for reliable AT27C020-90JU programming.
AT27C020-90JU 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:
- 90 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)
AT27C020-90JU FAQ
1.How can I place an order for AT27C020-90JU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C020-90JU 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 AT27C020-90JU reliable?
The price and inventory of AT27C020-90JU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C020-90JU is usually 5 days.
3.What payment methods are accepted for AT27C020-90JU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C020-90JU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C020-90JU?
AT27C020-90JU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C020-90JU 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 AT27C020-90JU?
For technical support, including AT27C020-90JU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C020-90JU requirements.
6.How does Aetrix verify that AT27C020-90JU is sourced from the original manufacturer or authorized distributors?
All AT27C020-90JU 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 AT27C020-90JU meets industry standards.
7.What is the process for return or replacement of AT27C020-90JU?
All AT27C020-90JU units undergo pre-shipment inspection (PSI). If there is an issue with AT27C020-90JU, 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 AT27C020-90JU part is unused and in its original packaging.
Return procedure for AT27C020-90JU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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