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Microchip Technology AT28C256-15UM/883-815
- Part No.:
- AT28C256-15UM/883-815
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-BCPGA
- Datasheet:
-
AT28C256-15UM/883-815.pdf
- Description:
- IC EEPROM 256KBIT PAR 28CPGA
- Quantity:
- Payment:
- Shipping:
Inventory:4,966
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Product details
Overview
AT28C256-15UM/883-815 from Microchip Technology is a military-grade 256-Kbit paged parallel EEPROM organized as 32,768 × 8, featuring 150 ns read access time, 3 ms or 10 ms page write cycle time, and single 5V ±10% supply operation. It supports hardware/software data protection and DATA Polling for write completion detection, deployed in avionics control modules requiring nonvolatile configuration storage with radiation-tolerant reliability.
For engineers reviewing the AT28C256-15UM/883-815 datasheet, AT28C256-15UM/883-815 pinout, AT28C256-15UM/883-815 application, or AT28C256-15UM/883-815 equivalent, this page delivers verified military-spec electrical parameters, JEDEC-compliant byte-wide pin mapping, endurance (10,000/100,000 cycles) and data retention (10 years), and precise package identification for 30-pin PGA packaging per MIL-STD-1835.
Technical Context
The AT28C256-15UM/883-815 implements a paged write architecture with a 64-byte internal latched buffer, enabling simultaneous programming of 1–64 bytes within a single page defined by address bits A6–A14. Its dual-line chip enable (CE) and output enable (OE) control logic allows static RAM-like read/write interfacing without external timing components.
It integrates VCC sense circuitry (write inhibit below 3.8 V), 5 ms power-on delay, noise filtering on WE/CE inputs (<15 ns rejection), and optional software data protection using three-step command sequences at addresses 5555H/2AAAH. Toggle Bit (I/O6) and DATA Polling (I/O7) provide real-time write status feedback independent of system clock.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Capacity | 256 Kbit (32,768 × 8) - provides full 32 KB nonvolatile storage for firmware boot code or calibration tables |
| Read Access Time | 150 ns - enables direct replacement of SRAM in legacy MIL-STD-1553 bus controllers without timing redesign |
| Page Write Cycle Time | 3 ms (F version) or 10 ms - determines minimum latency between consecutive page writes in telemetry logging systems |
| Endurance | 10,000 or 100,000 write/erase cycles - supports field-upgradable mission profiles with >5-year operational life |
| Data Retention | 10 years at -55°C to +125°C - meets MIL-PRF-38535 Class B requirements for long-term unpowered storage |
| Supply Voltage | 5 V ±10% - compatible with legacy 5 V TTL/CMOS logic families without level-shifting |
| Operating Temperature | -55°C to +125°C - qualified per MIL-STD-883 Method 1010 for extended-range aerospace deployment |
Pinout & Package
AT28C256-15UM/883-815 is packaged in a 30-pin Ceramic Pin Grid Array (PGA) per MIL-STD-1835 U-configuration, with pins arranged in two concentric rows (inner: 12 pins, outer: 18 pins), hermetically sealed for high-reliability military environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32 KB memory map; A6–A14 define page boundaries for 64-byte page writes |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel interface; I/O7 used for DATA Polling, I/O6 for Toggle Bit status indication during write cycles |
| CE | Chip Enable | Active-low device select; must be low with OE low and WE high for read access; initiates write when pulsed low with OE high |
| OE | Output Enable | Active-low output control; places I/O lines in high-impedance state when high, preventing bus contention |
| WE | Write Enable | Active-low write strobe; falling edge latches address/data; combined with CE for robust noise-immune write initiation |
| VCC | Power Supply | +5 V ±10% main supply; internal VCC sense disables writes below 3.8 V to prevent corruption during brownout |
| GND | Ground Reference | Signal and power ground reference; decoupling required per MIL-STD-1553B layout guidelines |
| DC (Pins 1, 17) | Don't Connect | No internal connection; must remain unconnected per CLCC package marking specification |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-Wide Pinout | Direct drop-in compatibility with industry-standard 28-pin EPROM/EEPROM sockets in legacy flight computers |
| Hardware Data Protection | VCC sensing, 5 ms power-on delay, and <15 ns noise filtering eliminate need for external reset supervisors in missile guidance units |
| Software Data Protection (SDP) | User-configurable 3-byte command sequence (AAH/55H/A0H) prevents accidental writes during power transitions in satellite attitude control systems |
| 64-Byte Page Register | Reduces host processor overhead by enabling burst writes of up to 64 bytes without readdressing-critical for real-time sensor calibration updates |
| Device Identification Area | 64-byte reserved EEPROM block (7FC0H–7FFFH) accessible via 12 V on A9 for unique unit serialization in depot-level maintenance tracking |
Applications
| Avionics Configuration Storage | Mission-Critical Boot Memory |
|---|---|
Use Scenario: Storing aircraft-specific navigation database checksums and sensor calibration coefficients in MIL-STD-1553B bus controllers. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing deterministic 150 ns read access during cold-start initialization sequences. Use Value: Eliminates reliance on external battery-backed SRAM while maintaining full compliance with DO-254 Level A design assurance requirements. |
Use Scenario: Holding bootloader firmware and secure key material in encrypted flight control processors operating across -55°C to +125°C. IC Role / Device Role / Timing Role: Primary boot memory mapped into CPU address space; supports fast page writes for field updates without system reset. Use Value: Enables secure over-the-air (OTA) updates via 64-byte page writes with hardware-enforced write inhibition during voltage transients. |
| Tactical Radio Firmware Storage | Spacecraft Telemetry Logging |
Use Scenario: Storing frequency-hopping algorithm parameters and cryptographic keys in manpack radios subjected to shock/vibration per MIL-STD-810G. IC Role / Device Role / Timing Role: Secure parameter store with software data protection enabled; accessed via parallel bus synchronized to baseband processor clock. Use Value: Prevents unauthorized firmware modification through SDP command sequence, meeting NSA Type 1 encryption module requirements. |
Use Scenario: Capturing radiation-hardened housekeeping data (voltage, temperature, error counters) during orbital eclipse periods in LEO satellites. IC Role / Device Role / Timing Role: High-reliability data logger using page write mode to batch telemetry packets every 500 ms without CPU intervention. Use Value: Achieves 10-year data retention at +85°C in vacuum, validated per MIL-PRF-38535 Class K screening for space applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar paged parallel EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-15JM/883 | 32-lead CERDIP package (vs. 30-pin PGA); identical electrical specs and military screening | Preferred for PCBs with existing DIP footprints; requires different socket or solder pad layout | Select when mechanical form factor compatibility with legacy board assemblies is required |
| AT28C256-15LM/883 | 32-pad CLCC package; same speed grade and endurance, but different thermal profile and mounting method | Suitable for surface-mount designs with high vibration tolerance needs; no through-hole mounting | Choose for new designs prioritizing hermetic sealing and reduced weight in airborne platforms |
Compared with AT28C256-15UM/883-815, the JM variant offers identical functionality in a through-hole CERDIP package for retrofit use, while the LM variant provides CLCC surface-mount compatibility with enhanced thermal cycling resistance-both retain full 150 ns read timing and 3/10 ms page write capability.
Availability
AT28C256-15UM/883-815 is available at Aetrix Electronics and suitable for avionics configuration storage, mission-critical boot memory, and tactical radio firmware storage requiring stable component supply under extended temperature and radiation-exposed conditions.
Supply support for AT28C256-15UM/883-815 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 Inc. is a global provider of microcontroller, mixed-signal, analog, and Flash-IP solutions, with headquarters in Chandler, Arizona, and manufacturing facilities certified to MIL-PRF-38535 standards.
The AT28C256 product line was developed specifically for high-reliability military and aerospace applications requiring radiation-tolerant, long-retention nonvolatile memory with deterministic timing and hardware/software write protection.
FAQ
What is the maximum page write size supported by the AT28C256-15UM/883-815?
The AT28C256-15UM/883-815 supports up to 64 bytes per page write operation, constrained by the internal 64-byte latch buffer. All bytes written in a single page cycle must reside within the same 64-byte boundary defined by address bits A6–A14; exceeding the 150 µs byte load cycle (tBLC) will terminate acceptance and initiate internal programming.
Does the AT28C256-15UM/883-815 require external high-voltage programming circuitry?
No, the AT28C256-15UM/883-815 operates from a single 5 V ±10% supply and does not require external high-voltage programming. Chip erase uses a 12 V pulse on A9, but standard byte and page writes use only VCC; the internal charge pump generates necessary programming voltages, eliminating need for external HV generators.
How is write completion detected on the AT28C256-15UM/883-815 without polling the entire memory array?
Write completion on the AT28C256-15UM/883-815 is detected via DATA Polling on I/O7 (complement of last written data until complete) or Toggle Bit behavior on I/O6 (repeated toggling until write ends). Both methods allow the host to monitor a single pin asynchronously, avoiding bus contention and reducing CPU overhead during programming.
What package type does the AT28C256-15UM/883-815 use, and how is it identified in the part marking?
The AT28C256-15UM/883-815 uses a 30-pin Ceramic Pin Grid Array (PGA) per MIL-STD-1835 U-configuration. Its top-side marking includes "%%UM/883" where "UM" denotes the 30-pin PGA package and "/883" indicates compliance with MIL-STD-883 test requirements, confirmed in Microchip DS20006344A-page 21.
Can the AT28C256-15UM/883-815 be used in systems requiring >100,000 write cycles?
Yes-the AT28C256-15UM/883-815 is rated for either 10,000 or 100,000 write/erase cycles depending on the specific wafer lot and endurance grade marked on the device. The "E" suffix in package marking (e.g., "15UM/883E") indicates the extended 100,000-cycle version; verify endurance grade via Microchip's trace code decoding per DS20006344A-page 21.
AT28C256-15UM/883-815 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-BCPGA
- Packaging:
- Box
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 10ms
- Access Time:
- 150 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-CPGA (13.97x16.51)
AT28C256-15UM/883-815 FAQ
1.How can I place an order for AT28C256-15UM/883-815 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256-15UM/883-815 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 AT28C256-15UM/883-815 reliable?
The price and inventory of AT28C256-15UM/883-815 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT28C256-15UM/883-815 is usually 5 days.
3.What payment methods are accepted for AT28C256-15UM/883-815?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256-15UM/883-815 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256-15UM/883-815?
AT28C256-15UM/883-815 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256-15UM/883-815 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 AT28C256-15UM/883-815?
For technical support, including AT28C256-15UM/883-815 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256-15UM/883-815 requirements.
6.How does Aetrix verify that AT28C256-15UM/883-815 is sourced from the original manufacturer or authorized distributors?
All AT28C256-15UM/883-815 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 AT28C256-15UM/883-815 meets industry standards.
7.What is the process for return or replacement of AT28C256-15UM/883-815?
All AT28C256-15UM/883-815 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256-15UM/883-815, 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 AT28C256-15UM/883-815 part is unused and in its original packaging.
Return procedure for AT28C256-15UM/883-815:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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