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Microchip Technology AT27C520-90SC
- Part No.:
- AT27C520-90SC
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT27C520-90SC.pdf
- Description:
- IC EPROM 512KBIT PARALLEL 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,716
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Product details
Overview
AT27C520-90SC from Atmel is a 524,288-bit (64K × 8) one-time programmable EPROM with multiplexed address/data bus, 90 ns read access time, 5V ±10% supply, and 20-pin SOIC package. It integrates latches for A0–A7 to share AD0–AD7 pins, reducing system chip count in microprocessor-based firmware storage applications.
For engineers reviewing the AT27C520-90SC datasheet, AT27C520-90SC pinout, AT27C520-90SC application, or AT27C520-90SC equivalent, key selection factors include OTP reliability, 90 ns read timing, 5V-only operation, CMOS/TTL compatibility, and industrial temperature support up to 85°C.
Technical Context
The AT27C520-90SC implements an internal address latch architecture where A0–A7 are multiplexed with AD0–AD7 via ALE control, enabling single-bus interfacing with 80C51 or Z80 families. Its Rapid™ programming algorithm uses 50 µs/byte pulses at VPP = 13.0 V and VCC = 6.5 V, verified per byte with up to 10 retries.
It supports four operating modes-Read, Output Disable, Address Latch Enable, and Rapid Program-controlled by OE/VPP and ALE logic levels. The device includes integrated product identification code (Manufacturer ID = 0x1E, Device ID = 0x9D), accessible via A9 high-voltage select and A8 toggle, used by industry-standard programmers for auto-algorithm selection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 524,288 bits (64K × 8); stores full firmware images for 8-bit microcontrollers without external memory management. |
| Access Time | 90 ns max (tACC); eliminates WAIT states on 11 MHz Z80 or 12 MHz 8051 systems running at 5V. |
| Supply Voltage | 5V ±10%; operates directly from standard logic rail-no dedicated programming voltage required during read mode. |
| Active Current | 20 mA max at 5 MHz; enables low-power embedded boot ROM usage with minimal thermal impact. |
| ESD Protection | 2,000V HBM; ensures robust handling during board assembly and in-circuit programming. |
| Latchup Immunity | 200 mA; prevents destructive latchup under transient overvoltage or ground bounce conditions. |
| Operating Temp | -40°C to +85°C (industrial grade); validated for use in automotive body control modules and industrial PLC firmware storage. |
Pinout & Package
AT27C520-90SC is supplied in a 20-lead, 0.300" wide plastic gull-wing SOIC (package code 20S), RoHS-compliant and JEDEC MS-013 compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A8–A15 | Address Inputs | Upper 8 address bits; non-multiplexed, directly drive row decoder for 64K address space. |
| AD0–AD7 | Address/Data Multiplexed I/O | Lower 8 address bits (latched on ALE high) and bidirectional data bus; reduces PCB trace count by 8 lines. |
| OE/VPP | Output Enable / Programming Supply | Active-low read enable; during programming, accepts 13.0 V ±0.25 V for oxide breakdown programming. |
| ALE | Address Latch Enable | High pulse captures AD0–AD7 as A0–A7 into internal latches; enables transparent multiplexed bus timing. |
| VCC | Power Supply | +5V ±10% main supply; powers all logic and memory array; requires local 0.1 µF ceramic decoupling. |
| GND | Ground Reference | Signal and power return; must be low-inductance connection to minimize noise coupling into AD0–AD7. |
Key Features
| Feature | Design Value |
|---|---|
| Rapid™ Programming | 50 µs/byte typical programming time with built-in verification loop-reduces production burn-in cycle time by >60% vs. legacy EPROMs. |
| Integrated ID Code | Manufacturer ID (0x1E) and Device ID (0x9D) readable via A9/A8 control-enables automated programmer validation and BOM traceability. |
| Multiplexed Bus Architecture | AD0–AD7 serve dual role as A0–A7 and data lines-eliminates need for external address latches in 8-bit MPU designs. |
| CMOS/TTL Compatibility | VIH = 2.0 V min, VOL = 0.4 V max at 2.1 mA-interoperates with both 5V TTL peripherals and modern CMOS logic without level shifters. |
| Industrial Temperature Range | Specified operation from -40°C to +85°C-qualified for deployment in motor drives, HVAC controllers, and factory automation firmware storage. |
Applications
| Embedded Boot ROM | Firmware Storage for MCU |
|---|---|
Use Scenario: Storing startup code for 8051-based medical diagnostic equipment requiring cold-boot reliability and zero firmware corruption risk. IC Role / Device Role / Timing Role: Non-volatile boot memory mapped to 0x0000–0xFFFF; accessed within 90 ns after reset release. Use Value: OTP architecture prevents accidental overwrite during field service; 2,000V ESD tolerance ensures survival during technician handling. | Use Scenario: Holding calibration tables and sensor compensation coefficients in industrial pressure transmitters with 10-year field life requirement. IC Role / Device Role / Timing Role: Read-only configuration memory accessed via Z80-compatible bus; no write cycles needed post-deployment. Use Value: 200 mA latchup immunity withstands 4–20 mA loop transients; -40°C to +85°C rating matches enclosure thermal profile. |
| Legacy System Replacement | Programmable Logic Configuration |
Use Scenario: Replacing obsolete 27C512 EPROMs in telecom line card controllers where PCB layout cannot accommodate new footprint. IC Role / Device Role / Timing Role: Pin-compatible drop-in replacement (20-pin SOIC, same pinout); identical ALE/OE timing interface. Use Value: Same 90 ns tACC and 5V supply eliminates timing revalidation; Rapid™ programming maintains existing production programmer settings. | Use Scenario: Storing PAL/GAL fuse map data in test equipment jigs where configuration must survive repeated power cycles. IC Role / Device Role / Timing Role: Static configuration store accessed once at power-up; no dynamic writes required during operation. Use Value: OTP permanence guarantees configuration integrity across 100,000+ power cycles; 0.1 µF decoupling meets system-level noise immunity specs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar OTP EPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT27C512-90PC | 512 Kbit (64K × 8), same speed grade, but 28-pin PDIP package; lacks TSSOP/SOIC pinout compatibility. | Used in through-hole prototyping or legacy repair; not suitable for surface-mount production with AT27C520-90SC footprint. | Select only if board uses 28-pin socket or manual soldering is acceptable; verify PCB pad layout and thermal relief. |
| MX27C512AP-90 | Same density and 90 ns speed, but requires 12.5 V VPP and has higher ICC (25 mA); no integrated ID code. | Requires modified programmer voltage setup and lacks auto-ID verification; may increase production test time. | Acceptable for cost-sensitive builds where ID code and Rapid™ programming are non-critical; validate VPP regulation stability. |
Compared with AT27C520-90SC, AT27C512-90PC offers identical functionality but demands PCB redesign due to 28-pin DIP footprint, while MX27C512AP-90 introduces higher programming voltage complexity and removes ID-based auto-detection-both trade off production efficiency for marginal cost savings.
Availability
AT27C520-90SC is available at Aetrix Electronics and suitable for industrial control systems, legacy MCU boot applications, and embedded instrumentation requiring stable component supply and long-term obsolescence management.
Supply support for AT27C520-90SC 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 company specializing in microcontrollers, non-volatile memory, and programmable logic, later acquired by Microchip Technology in 2016.
The AT27C520 belongs to Atmel's 27C-series OTP EPROM product line, designed specifically for reliable, low-cost firmware storage in 8-bit microprocessor systems where reprogrammability is unnecessary and data permanence is critical.
FAQ
What is the maximum operating frequency supported by the AT27C520-90SC?
The AT27C520-90SC does not operate at a clock frequency-it is a static memory device. Its 90 ns access time (tACC) supports reliable read operation with microprocessors running up to approximately 11 MHz (e.g., Z80) or 12 MHz (e.g., 8051) without WAIT states. Timing is governed by address setup/hold and OE delay specifications, not a system clock input.
Can the AT27C520-90SC be programmed in-circuit?
No, the AT27C520-90SC requires external EPROM programmers capable of delivering 13.0 V ±0.25 V to the OE/VPP pin and 6.5 V ±0.25 V to VCC during programming. In-circuit programming is not supported due to lack of on-chip charge pumps and strict voltage sequencing requirements defined in the AC Programming Characteristics table.
Does the AT27C520-90SC support both commercial and industrial temperature ranges?
Yes-the "C" suffix in AT27C520-90SC denotes the commercial temperature range (0°C to +70°C). For industrial operation (-40°C to +85°C), the correct ordering code is AT27C520-90SI. Both share identical electrical specifications except for temperature qualification and screening.
What decoupling capacitors are required for stable AT27C520-90SC operation?
The AT27C520-90SC requires a 0.1 µF ceramic capacitor placed between VCC and GND, mounted as close as possible to the device pins. For systems with multiple EPROMs, a 4.7 µF bulk electrolytic capacitor should also be added near the power entry point to suppress low-frequency supply ripple and maintain stable read timing.
How is the Integrated Product Identification Code read from the AT27C520-90SC?
The AT27C520-90SC ID code is read by holding A10–A15 low, setting A9 to 12.0 V (VH), and toggling A8 between low (to read Manufacturer ID 0x1E) and high (to read Device ID 0x9D), with OE/VPP and ALE held low. This mode is supported only during programming-voltage conditions and requires compatible programmer hardware.
AT27C520-90SC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EPROM
- Technology:
- EPROM - OTP
- Memory Size:
- 512Kbit
- Memory Organization:
- 64K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- -
- Access Time:
- 90 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
AT27C520-90SC FAQ
1.How can I place an order for AT27C520-90SC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT27C520-90SC 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 AT27C520-90SC reliable?
The price and inventory of AT27C520-90SC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT27C520-90SC is usually 5 days.
3.What payment methods are accepted for AT27C520-90SC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT27C520-90SC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT27C520-90SC?
AT27C520-90SC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT27C520-90SC 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 AT27C520-90SC?
For technical support, including AT27C520-90SC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT27C520-90SC requirements.
6.How does Aetrix verify that AT27C520-90SC is sourced from the original manufacturer or authorized distributors?
All AT27C520-90SC 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 AT27C520-90SC meets industry standards.
7.What is the process for return or replacement of AT27C520-90SC?
All AT27C520-90SC units undergo pre-shipment inspection (PSI). If there is an issue with AT27C520-90SC, 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 AT27C520-90SC part is unused and in its original packaging.
Return procedure for AT27C520-90SC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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