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Microchip Technology AT27C020-70PC
- Part No.:
- AT27C020-70PC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-DIP (0.600", 15.24mm)
- Datasheet:
-
AT27C020-70PC.pdf
- Description:
- IC EPROM 2MBIT PARALLEL 32DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,048
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Product details
Overview
AT27C020-70PC from Atmel is a 2-Mbit (256K × 8) one-time programmable EPROM designed for firmware storage in microprocessor systems. It delivers 70 ns read access time, operates on a single 5V ±10% supply, and supports commercial temperature range (0°C to 70°C) in a 32-lead 600-mil PDIP package. Its dual-line control (CE/OE) prevents bus contention in embedded boot memory applications.
For engineers reviewing the AT27C020-70PC datasheet, AT27C020-70PC pinout, AT27C020-70PC application, or AT27C020-70PC equivalent, key selection criteria include OTP reliability, 55–70 ns read timing, 100 µA max standby current, and compatibility with legacy 5V microcontroller buses requiring non-volatile program storage without write endurance constraints.
Technical Context
The AT27C020-70PC implements a CMOS-based OTP EPROM architecture with address decoding for A0–A17 (18-bit), 8-bit parallel data outputs (O0–O7), and two independent enable controls (CE and OE). Its Rapid™ programming algorithm uses 100 µs/byte pulses at VPP = 13.0 V and VCC = 6.5 V, followed by verify cycles per byte.
It features integrated product identification (via A9 high-voltage mode and A0 toggle), 2,000V ESD protection, and 200 mA latch-up immunity. The device enters high-impedance output disable during OE = VIH or CE = VIH, and supports rapid transition between active (25 mA @ 5 MHz) and standby (<100 µA) modes via CE control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2,097,152 bits (256K × 8) - provides full firmware image storage for 8-bit microcontrollers without external paging logic. |
| Read Access Time | 70 ns max - eliminates WAIT states on 14 MHz Z80, 8051, or 68K-based systems operating at ≤14 MHz. |
| VCC Supply | 5V ±10% - compatible with standard TTL/CMOS logic rails; no auxiliary voltage required for read operation. |
| Standby Current | 100 µA max - enables low-power retention in battery-backed or intermittently powered systems. |
| Programming Voltage | VPP = 13.0 V ±0.25 V - requires dedicated EPROM programmer with high-voltage pulse generation and verification capability. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade industrial control panels and office equipment. |
| ESD Protection | 2,000V HBM - meets JEDEC JESD22-A114 reliability requirements for handling and board assembly. |
Pinout & Package
AT27C020-70PC is supplied in a 32-lead, 0.600" wide plastic dual inline package (PDIP), JEDEC MS-011 compliant. Pin 1 is index-marked; pins are numbered counter-clockwise from top-left corner when viewed from top with notch or dot oriented left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address Inputs | 18-bit address bus interface; selects one of 256K bytes; driven by microprocessor address lines A0–A17. |
| O0–O7 | Data Outputs | 8-bit bidirectional data bus outputs; drive TTL/CMOS loads directly; high-impedance when CE or OE inactive. |
| CE | Chip Enable | Active-low global chip select; must be asserted before OE to enable output drivers; controls power state transition. |
| OE | Output Enable | Active-low output gate; allows shared bus operation without tristate conflicts when CE is active but OE is high. |
| PGM | Program Strobe | Active-low programming pulse input; initiates 100 µs write cycle when VPP = 13 V and address valid. |
| VPP | Programming Voltage | 13.0 V input during programming only; must be applied after VCC and removed before VCC per sequencing rules. |
| VCC | Power Supply | +5V supply for read and standby; elevated to +6.5V during programming; requires local 0.1 µF ceramic decoupling. |
| GND | Ground Reference | Signal and power return; must be connected to system ground plane with low-inductance path for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming Algorithm | 100 µs/byte typical programming time with automatic verify-and-reprogram loop ensures field-programmable reliability without manual intervention. |
| Integrated Product ID Code | Manufacturer (0x1E) and device code (0x86) readable via A9 = 12.0 V and A0 toggle - enables automated programmer recognition and algorithm selection. |
| Two-Line Control (CE/OE) | Independent chip and output enables allow flexible bus arbitration in multi-device systems, eliminating need for external bus transceivers. |
| JEDEC-Standard Packages | 32-lead PDIP (32P6), PLCC (32J), and TSOP (32T) options support legacy socketing, surface-mount rework, and space-constrained designs. |
| High-Reliability CMOS Process | 2,000V ESD rating and 200 mA latch-up immunity ensure robustness during handling, PCB assembly, and long-term operation in industrial environments. |
Applications
| Industrial PLC Firmware Storage | Legacy Microcontroller Boot ROM |
|---|---|
|
Use Scenario: Storing fixed ladder logic firmware in programmable logic controllers where updates occur infrequently but data integrity is critical over 10+ year deployments. IC Role / Device Role / Timing Role: Non-volatile boot memory mapped to CPU address space; accessed during power-on reset sequence with strict 70 ns timing window. Use Value: OTP architecture prevents accidental overwrite; 70 ns access matches 14 MHz 8051 derivatives; 100 µA standby minimizes control cabinet standby power draw. |
Use Scenario: Providing immutable BIOS or monitor code for vintage 8-bit development systems (e.g., Z80-based SBCs) used in education and retro-computing labs. IC Role / Device Role / Timing Role: Primary read-only instruction store; decoded via A0–A17 and enabled by CE/OE to isolate from I/O peripherals during execution. Use Value: PDIP package enables socket-based replacement; 5V-only operation simplifies power design; JEDEC pinout ensures compatibility with existing ZIF programmers. |
| Automotive Instrument Cluster Calibration Data | Medical Device Configuration Memory |
|
Use Scenario: Holding calibrated sensor offsets and display lookup tables in analog-digital instrument clusters where firmware changes require dealer-level reprogramming. IC Role / Device Role / Timing Role: Static configuration memory accessed during startup; isolated from main MCU bus except during initialization to avoid interference. Use Value: Automotive-grade (-40°C to 125°C) variants exist (e.g., AT27C020-90PA); OTP prevents runtime corruption; 2,000V ESD withstands assembly line static discharge. |
Use Scenario: Storing FDA-approved device calibration constants and safety-critical operational parameters in Class II medical analyzers requiring traceable, unalterable configuration. IC Role / Device Role / Timing Role: Secure, write-once parameter store; read-accessed only during self-test and power-up; physically write-protected after factory programming. Use Value: No wear-out mechanism ensures >20-year data retention; 100 µA standby supports battery backup; product ID code enables audit trail for device revision tracking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM27C256B-120EC | 256K × 8 OTP EPROM; 120 ns access; 5V only; 28-pin DIP; no VPP pin - uses internal charge pump for programming. | Lacks separate VPP pin and rapid programming; slower timing limits use in high-speed 8051/Z80 systems. | Select when board layout lacks VPP routing or when 120 ns timing suffices and cost is primary constraint. |
| MX27C256-12PC | 256K × 8 OTP EPROM; 120 ns access; 5V ±10%; 28-pin DIP; requires 25 V VPP; no integrated ID code. | No product ID feature; higher VPP requirement increases programmer complexity; no rapid algorithm support. | Choose for legacy systems already using MX27C256 toolchains; avoid if automated ID-based programming or fast programming is needed. |
Compared with AM27C256B-120EC and MX27C256-12PC, the AT27C020-70PC offers faster 70 ns access, integrated ID coding for reliable programmer interoperability, and a verified 100 µs/byte rapid programming algorithm - making it preferable for new designs requiring tight timing margins and production-line programming efficiency.
Availability
AT27C020-70PC is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, and medical device configuration memory requiring stable component supply across extended product lifecycles.
Supply support for AT27C020-70PC 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, non-volatile memory, and RF solutions before its acquisition by Microchip Technology in 2016.
The AT27C020 belongs to Atmel's 27C-series OTP EPROM family, engineered for reliable, low-power, pin-compatible replacements of UV-erasable EPROMs in cost-sensitive industrial and embedded systems requiring permanent firmware storage.
FAQ
What is the maximum read access time specified for the AT27C020-70PC?
The AT27C020-70PC has a maximum read access time of 70 ns under commercial temperature conditions (0°C to 70°C) and VCC = 5V ±10%. This value is guaranteed across all operating voltages and temperatures within its rated range, enabling direct interfacing with 14 MHz microprocessors without wait-state insertion. The AT27C020-70PC achieves this performance using optimized CMOS decoding and output driver circuitry.
Does the AT27C020-70PC require a separate programming voltage, and what is its value?
Yes, the AT27C020-70PC requires a dedicated programming voltage (VPP) of 13.0 V ±0.25 V applied to the VPP pin during programming operations. This voltage must be sequenced after VCC and removed before VCC to prevent damage. The AT27C020-70PC does not support internal charge-pump programming - external 13 V supply and precise timing control are mandatory for successful byte programming.
Can the AT27C020-70PC be used in place of a UV-erasable EPROM like the 27C256?
Yes, the AT27C020-70PC is a functional and pin-compatible replacement for 27C256-family devices in 32-pin PDIP sockets, offering identical 256K × 8 organization and 5V read operation. However, the AT27C020-70PC is one-time programmable and lacks UV erasure - it replaces UV EPROMs where field reprogramming is unnecessary and permanent firmware storage is preferred.
What is the purpose of the PGM pin on the AT27C020-70PC?
On the AT27C020-70PC, the PGM (Program Strobe) pin is an active-low input that initiates a 100 µs programming pulse when asserted with valid address and data present. It synchronizes the internal programming algorithm and triggers the Rapid™ verify-and-reprogram sequence. The AT27C020-70PC requires PGM assertion only during programming - it remains high (VIH) during all read and standby modes.
How does the AT27C020-70PC support product identification during automated programming?
The AT27C020-70PC supports electronic product identification via its Integrated Product Identification Code: applying 12.0 V to A9 and toggling A0 reads manufacturer ID (0x1E) or device code (0x86) on O0–O7. This feature allows programmers to auto-detect the AT27C020-70PC and select correct algorithms/voltages - eliminating manual part selection errors in high-volume programming workflows.
AT27C020-70PC 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:
- 70 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
AT27C020-70PC FAQ
1.How can I place an order for AT27C020-70PC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C020-70PC 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 AT27C020-70PC reliable?
The price and inventory of AT27C020-70PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C020-70PC is usually 5 days.
3.What payment methods are accepted for AT27C020-70PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C020-70PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C020-70PC?
AT27C020-70PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C020-70PC 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 AT27C020-70PC?
For technical support, including AT27C020-70PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C020-70PC requirements.
6.How does Aetrix verify that AT27C020-70PC is sourced from the original manufacturer or authorized distributors?
All AT27C020-70PC 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 AT27C020-70PC meets industry standards.
7.What is the process for return or replacement of AT27C020-70PC?
All AT27C020-70PC units undergo pre-shipment inspection (PSI). If there is an issue with AT27C020-70PC, 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 AT27C020-70PC part is unused and in its original packaging.
Return procedure for AT27C020-70PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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