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Microchip Technology AT27C020-90PU
- Part No.:
- AT27C020-90PU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-DIP (0.600", 15.24mm)
- Datasheet:
-
AT27C020-90PU.pdf
- Description:
- IC EPROM 2MBIT PARALLEL 32DIP
- Quantity:
- Payment:
- Shipping:
Inventory:679
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Product details
Overview
AT27C020-90PU 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 PDIP package. It delivers fast, low-latency firmware storage for microprocessor systems without WAIT states and supports industrial temperature range (–40°C to +85°C).
For engineers reviewing the AT27C020-90PU datasheet, AT27C020-90PU pinout, AT27C020-90PU application, or AT27C020-90PU equivalent, key selection factors include verified 55ns tACC timing, CMOS/TTL-compatible I/O, rapid 100µs/byte programming, integrated product ID code, and dual-line control (CE/OE) for bus contention management.
Technical Context
The AT27C020-90PU 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 and OE) enables flexible memory-mapped or I/O-mapped system integration.
It operates in three primary modes: Read (CE=OE=VIL), Standby (CE=VIH), and Rapid Program (CE=VIL, OE=VIH, PGM pulsed at 100µs width with VPP=13.0V). The device integrates on-chip product identification logic (A9=12.0V, A0 toggled) to auto-select programming algorithms in production equipment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256K × 8 bits (2,097,152-bit OTP EPROM) - supports full firmware image storage for 8-bit microcontrollers without external buffering |
| Read access time (tACC) | 90 ns max - ensures compatibility with 10 MHz Z80, 8051, and 68K-based systems requiring deterministic timing |
| VCC supply | 5 V ±10% - eliminates need for auxiliary voltage rails; compatible with legacy TTL/CMOS logic families |
| Active current (ICC) | 25 mA max at 5 MHz - enables direct interface with standard microprocessor buses without current-limiting resistors |
| Standby current (ISB1) | 100 µA max (CMOS CE mode) - reduces power in idle states for battery-backed or energy-sensitive embedded controllers |
| Programming voltage (VPP) | 13.0 V ±0.25 V - requires dedicated programming supply; not connected to VCC during normal operation |
| ESD protection | 2,000 V HBM - meets industrial handling requirements without additional input protection circuitry |
Pinout & Package
AT27C020-90PU is supplied in a 32-lead plastic dual inline package (PDIP), 0.600" wide, JEDEC MS-016 compliant, with matte tin lead finish. Pin 1 is marked by a notch or dot; leads are gull-wing shaped with 2.54 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address inputs | 18-bit parallel address bus; fully decoded internally - no external address latching required for byte-wide access |
| O0–O7 | Data outputs | CMOS/TTL-compatible bidirectional outputs; high-impedance when CE or OE inactive - prevents bus contention |
| CE | Chip enable | Primary device select; must be VIL for read/program - used for memory-mapped decode in multi-chip systems |
| OE | Output enable | Secondary output gate; controls data bus drive timing independently of CE - enables shared-bus arbitration |
| PGM | Program strobe | Edge-triggered programming pulse input; accepts 100 µs width pulses at VPP = 13.0 V - initiates byte programming cycle |
| VPP | Programming voltage | 13.0 V programming supply input; must be applied before/with VCC and removed after VCC - critical for oxide breakdown reliability |
| VCC | Power supply | +5 V ±10% main supply; powers logic and outputs in read mode - decoupling capacitor (0.1 µF ceramic) required at pin |
| GND | Ground reference | Signal and power return; must be low-inductance connection - shared with system ground plane for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Rapid programming algorithm | 100 µs/byte typical - reduces production programming time by >5× vs. conventional EPROMs; includes auto-verify/reprogram loop |
| Integrated product ID code | Manufacturer ID (0x1E) and device ID (0x86) readable via A9=12.0 V and A0 toggle - enables automatic algorithm selection in gang programmers |
| Two-line control (CE/OE) | Independent chip and output enables - allows interleaved memory access and avoids bus conflicts in multi-peripheral systems |
| Industrial temperature range | –40°C to +85°C operation - qualified for use in factory automation, instrumentation, and telecom line cards without derating |
| Green packaging | Pb/halide-free PDIP - complies with RoHS Directive 2011/65/EU without requiring process requalification |
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: Non-volatile boot-time firmware repository accessed via 8051 or 80C188 address/data bus. Use Value: 90 ns tACC ensures zero-wait-state execution; 256K capacity holds full runtime firmware plus diagnostics - eliminating disk or flash boot delays. |
Use Scenario: Providing immutable startup code and hardware initialization routines for vintage 8-bit embedded systems. IC Role / Device Role / Timing Role: Parallel-addressed ROM mapped to 0x0000–0x3FFFF address space; CE tied to address decoder output. Use Value: CMOS/TTL compatibility guarantees direct interface with 74LS/HC logic; 100 µA standby current extends battery backup life in maintenance mode. |
| Automated Test Equipment (ATE) Pattern Memory | Medical Device Calibration Data Storage |
Use Scenario: Holding digital stimulus patterns and expected response vectors in semiconductor test handlers. IC Role / Device Role / Timing Role: High-speed parallel memory accessed synchronously with pattern generator clock (≤11 MHz). Use Value: 55 ns tACC supports 10+ MHz pattern rates; OTP nature prevents accidental overwrite during field calibration or firmware updates. |
Use Scenario: Storing factory-trimmed sensor offset/gain coefficients and safety-critical configuration parameters in Class II medical instruments. IC Role / Device Role / Timing Role: Secure, unalterable data store accessed during power-on self-test (POST) prior to analog signal processing. Use Value: 2,000 V ESD rating protects against handling damage during assembly; industrial temp range ensures reliability across clinical environments. |
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 (256 Kbit), same 90 ns speed, identical PDIP-32 package and pinout | Lower density - suitable only where firmware fits ≤32 KB; lacks integrated ID code | Select when memory footprint is smaller and cost sensitivity outweighs future scalability |
| MX27C256-90PC | 32K × 8-bit OTP EPROM, 90 ns, PDIP-28 package - different pin count and layout | Requires PCB redesign due to 28-pin vs. 32-pin footprint; no A16/A17 or PGM pin | Choose only for legacy board reuse where AT27C020-90PU's 256K capacity is unnecessary |
Compared with AT27C256B-90PU and MX27C256-90PC, the AT27C020-90PU provides 8× more storage in the same package while retaining rapid programming and ID code features - making it optimal for next-generation firmware consolidation without layout changes.
Availability
AT27C020-90PU is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, automated test equipment pattern memory, and medical device calibration data storage requiring stable component supply and long-term obsolescence support.
Supply support for AT27C020-90PU 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 (now part of Microchip Technology) designed high-reliability non-volatile memory and microcontroller solutions for industrial, automotive, and communications markets before its 2016 acquisition.
The AT27C020 belongs to Atmel's OTP EPROM product line, engineered for firmware integrity and production programming efficiency in cost-sensitive, high-volume embedded systems where reprogrammability is unnecessary.
FAQ
What is the maximum operating temperature range for the AT27C020-90PU?
The AT27C020-90PU is rated for industrial temperature operation from –40°C to +85°C. This range is validated per the datasheet's "Operating temperature (case)" specification under the Ind. grade designation. The device maintains full DC and AC parameter compliance across this range, including 90 ns tACC and 100 µA ISB1 standby current. AT27C020-90PU does not support automotive-grade extended temperatures (–40°C to +125°C), which apply only to the -90AU variant.
Can the AT27C020-90PU be programmed in-circuit?
No, the AT27C020-90PU cannot be reliably programmed in-circuit. Programming requires VPP = 13.0 V ±0.25 V applied to the VPP pin, which exceeds standard system supply rails and risks damaging adjacent components. The datasheet mandates external programming equipment with precise voltage control, 0.1 µF VPP-to-GND decoupling, and strict sequencing (VCC applied before/with VPP). AT27C020-90PU is intended for factory programming prior to board assembly.
Does the AT27C020-90PU support byte-level erase or reprogramming?
No, the AT27C020-90PU is a one-time programmable (OTP) EPROM and does not support erasure or reprogramming. Once a bit is programmed from '1' to '0', it cannot be reverted. The device lacks UV-erasable quartz window or electrical erase circuitry. Programming is irreversible - verification occurs per-byte during the rapid programming sequence, but failed bytes require device replacement. AT27C020-90PU is designed for final firmware images, not development iteration.
What decoupling capacitors are required for stable operation of the AT27C020-90PU?
The AT27C020-90PU 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 supply entry point for boards with multiple EPROMs. These values are specified in the "System considerations" section to suppress transient voltage excursions during CE switching and stabilize VCC under active current draw (25 mA max). Omitting either capacitor risks timing violations or latchup.
How is the product identification code read from the AT27C020-90PU?
The AT27C020-90PU product identification code is read by applying VH = 12.0 V ±0.5 V to pin A9 while holding A1–A17 at VIL, then toggling A0: low (VIL) reads the manufacturer ID (0x1E), high (VIH) reads the device ID (0x86). Both bytes appear on O7–O0 during a standard read cycle with CE=OE=VIL. This feature is used by automated programmers to auto-detect the device and select correct programming algorithms - AT27C020-90PU implements this per Table 5-8 and Figure 5-1.
AT27C020-90PU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-DIP (0.600", 15.24mm)
- 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:
- Through Hole
- Supplier Device Package:
- 32-PDIP
AT27C020-90PU FAQ
1.How can I place an order for AT27C020-90PU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C020-90PU 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 AT27C020-90PU reliable?
The price and inventory of AT27C020-90PU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C020-90PU is usually 5 days.
3.What payment methods are accepted for AT27C020-90PU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C020-90PU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C020-90PU?
AT27C020-90PU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C020-90PU 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 AT27C020-90PU?
For technical support, including AT27C020-90PU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C020-90PU requirements.
6.How does Aetrix verify that AT27C020-90PU is sourced from the original manufacturer or authorized distributors?
All AT27C020-90PU 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 AT27C020-90PU meets industry standards.
7.What is the process for return or replacement of AT27C020-90PU?
All AT27C020-90PU units undergo pre-shipment inspection (PSI). If there is an issue with AT27C020-90PU, 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 AT27C020-90PU part is unused and in its original packaging.
Return procedure for AT27C020-90PU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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