My Inquiry
My Account
Microchip Technology AT28C256-15UM/883
- Part No.:
- AT28C256-15UM/883
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-BCPGA
- Datasheet:
-
AT28C256-15UM/883.pdf
- Description:
- IC EEPROM 256KBIT PAR 28CPGA
- Quantity:
- Payment:
- Shipping:
Inventory:2,083
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AT28C256-15UM/883 from Microchip Technology is a military-grade 256-Kbit paged parallel EEPROM organized as 32,768 × 8, featuring 150 ns read access time, 10 ms maximum page write cycle time, and single 5V ±10% supply operation. It supports hardware and software data protection, DATA polling for write completion detection, and operates across –55°C to +125°C for avionics and defense subsystems requiring nonvolatile configuration storage.
For engineers reviewing the AT28C256-15UM/883 datasheet, AT28C256-15UM/883 pinout, AT28C256-15UM/883 application, or AT28C256-15UM/883 equivalent, this device serves as a drop-in replacement for legacy byte-wide EEPROMs in MIL-STD-883-compliant systems where endurance (10,000 cycles), 10-year data retention, and JEDEC-standard pinout are mandatory.
Technical Context
The AT28C256-15UM/883 implements a paged write architecture with a 64-byte internal latch, enabling simultaneous programming of 1–64 bytes per cycle while freeing the address/data bus during internal timing. Its dual-line chip enable (CE) and output enable (OE) control allows precise bus contention management in multiprocessor memory maps.
It integrates VCC sense circuitry that inhibits writes below 3.8 V, a 5 ms power-on delay timer, noise filtering on WE/CE inputs (<15 ns pulse rejection), and optional software data protection (SDP) activated via a three-byte command sequence at addresses 5555H/2AAAH/5555H - all verified under MIL-PRF-38535 Class B screening.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8) - provides full 16-bit address space for firmware parameter tables and calibration data storage |
| Read Access Time | 150 ns max - enables direct interface with 5 MHz Z80, 80C86, or MIL-STD-1553B host processors without wait states |
| Page Write Cycle | ≤10 ms - reduces system-level write latency versus byte-by-byte programming; supports burst configuration updates |
| Endurance | 10,000 write/erase cycles - validated per MIL-STD-883 Method 1032 for mission-critical reprogramming in field-deployed systems |
| Data Retention | 10 years at +125°C - meets long-term storage requirements for sealed avionics modules with no maintenance access |
| Supply Voltage | 5 V ±10% - compatible with standard military DC-DC converters and eliminates need for auxiliary voltage rails |
| Operating Temp | –55°C to +125°C - qualified per MIL-STD-883 Condition A for extended-range operation in airborne and space environments |
Pinout & Package
AT28C256-15UM/883 is supplied in a 30-pin ceramic Pin Grid Array (PGA) package compliant with MIL-STD-1835 U-28 configuration, with 2.54 mm pin pitch and hermetically sealed construction. Pin 1 is indexed at top-left corner; pins 1 and 17 are designated "Don't Connect" per datasheet DS20006344A-page 4.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word addressing; A6–A14 define page boundaries for 64-byte write operations |
| I/O0–I/O7 | Bidirectional Data Bus | CMOS/TTL-compatible 8-bit data path; I/O7 used for DATA polling, I/O6 for toggle-bit write status indication |
| CE | Chip Enable | Active-low chip select; must be stable before address setup; controls device selection in multi-chip memory arrays |
| OE | Output Enable | Active-low output gate; decouples data bus during standby or write cycles to prevent contention |
| WE | Write Enable | Active-low write strobe; falling edge latches data; combined with CE determines write initiation mode (WE- or CE-controlled) |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and memory array; includes internal VCC sense for write inhibition |
| GND | Ground Reference | Signal and power ground return; requires low-inductance connection to minimize noise coupling during page writes |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC Byte-Wide Pinout | Direct compatibility with legacy 27C256/27C512 socket layouts and PCB footprints - no layout redesign required |
| Hardware Data Protection | VCC sense + 5 ms power-on delay + WE/CE noise filtering prevents spurious writes during brown-out or EMI events |
| Software Data Protection (SDP) | User-configurable lock via 3-byte command sequence; remains active through power cycles and protects entire array |
| DATA Polling & Toggle Bit | Real-time write status feedback on I/O7 (complement-to-data) and I/O6 (toggling) - eliminates need for fixed delay timers |
| 64-Byte Page Register | Enables burst loading of configuration blocks; reduces host CPU overhead by >90% vs. sequential byte writes |
Applications
| Avionics Flight Control | Military Radio Calibration |
|---|---|
Use Scenario: Storing real-time trim coefficients and sensor bias offsets in fly-by-wire flight computers operating at –55°C to +125°C. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing immediate read access at power-up and secure page-write capability during in-flight recalibration. Use Value: 150 ns read time ensures deterministic response within 200 ns interrupt latency budgets; 10,000-cycle endurance supports 10+ years of scheduled maintenance updates. |
Use Scenario: Holding RF front-end calibration constants in SDR transceivers deployed in electronic warfare platforms. IC Role / Device Role / Timing Role: Secure parameter store with SDP enabled to prevent accidental overwrites during hot-swap module replacement. Use Value: Software data protection prevents corruption during field upgrades; 10-year data retention eliminates need for battery-backed SRAM or periodic reflash. |
| Tactical Vehicle Telematics | Spacecraft Onboard Computer |
Use Scenario: Logging vehicle health metrics and mission logs in armored ground vehicles exposed to shock/vibration and wide thermal swings. IC Role / Device Role / Timing Role: Ruggedized nonvolatile memory for event-driven logging with guaranteed write completion via DATA polling. Use Value: Page write mode enables efficient storage of 64-byte CAN message buffers; MIL-STD-883 qualification ensures survivability under 30g shock profiles. |
Use Scenario: Storing boot firmware patches and radiation-hardened configuration tables in LEO satellite OBCs. IC Role / Device Role / Timing Role: Radiation-tolerant (not rad-hard, but screened) EEPROM for critical startup parameters with zero write failures due to SEU-induced glitches. Use Value: Hardware write inhibit (VCC sense + noise filter) prevents bit flips from TID-induced supply droop; hermetic PGA package resists outgassing in vacuum. |
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 | Same die, 32-lead CERDIP package instead of 30-pin PGA; identical AC/DC specs and MIL-STD-883 screening | Requires PCB footprint change; preferred for through-hole assembly or legacy board reuse where PGA sockets unavailable | Select when mechanical mounting constraints favor DIP-style packages or existing tooling supports CERDIP insertion |
| DS2502-E48+ | 1-Wire serial EEPROM (48-bit ID + 1024-bit user memory); no parallel bus, no page write, 5 ms write time, industrial temp only | Lacks JEDEC pinout and parallel interface; suitable only for low-pin-count microcontroller peripherals, not MPU bus interfacing | Choose only for ultra-low-pin-count designs where bus sharing and minimal I/O usage outweigh speed and capacity trade-offs |
Compared with AT28C256-15UM/883, the AT28C256-15JM/883 offers identical functionality in a different package form factor, while the DS2502-E48+ sacrifices parallel bandwidth and military temperature range for extreme integration simplicity - making the former a true drop-in alternative and the latter a functionally divergent option for non-bus-critical roles.
Availability
AT28C256-15UM/883 is available at Aetrix Electronics and suitable for avionics flight control, military radio calibration, tactical vehicle telematics, and spacecraft onboard computer applications requiring stable component supply under extended temperature and radiation-aware conditions.
Supply support for AT28C256-15UM/883 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 is a global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions, with ISO 9001-certified manufacturing and MIL-PRF-38535-qualified wafer fabrication.
The AT28C256 product line was developed for high-reliability embedded systems requiring radiation-tolerant, temperature-stable, and long-life nonvolatile storage - specifically targeting defense, aerospace, and industrial control markets where data integrity cannot be compromised.
FAQ
What is the maximum page write size supported by the AT28C256-15UM/883?
The AT28C256-15UM/883 supports up to 64 bytes per page write operation, with all bytes required to reside on the same page defined by address bits A6–A14. Each successive byte must be loaded within 150 µs of the prior one; exceeding this interval triggers automatic internal programming. This capability is confirmed in Section 6.8 and Table 6-4 of datasheet DS20006344A.
Does the AT28C256-15UM/883 require external high-voltage programming circuitry?
No, the AT28C256-15UM/883 operates from a single 5V ±10% supply and does not require external 12V programming voltages for normal page or byte writes. Only the optional chip erase mode (Section 6.10) uses 12.0 V ±0.5 V on OE, which is not needed for routine operation. All standard write functions use standard logic-level signals.
How is write completion detected on the AT28C256-15UM/883 without using a fixed delay?
Write completion on the AT28C256-15UM/883 is detected via DATA polling on I/O7 (complement-to-data behavior) or toggle-bit monitoring on I/O6 (repeated toggling until write ends). Both methods are fully characterized and do not rely on worst-case timing margins - enabling deterministic, latency-optimized firmware design per Sections 6.14 and 6.16.
Is the AT28C256-15UM/883 pin-compatible with the commercial-grade AT28C256-15PU?
Yes, the AT28C256-15UM/883 shares identical pinout, signal definitions, and timing specifications with the commercial AT28C256-15PU, as both conform to JEDEC-standard byte-wide EEPROM pin assignments. However, the UM/883 variant adds MIL-STD-883 screening, extended temperature range (–55°C to +125°C), and hermetic PGA packaging - requiring validation of thermal and mechanical interfaces in the target system.
What endurance rating applies to the AT28C256-15UM/883 under military temperature conditions?
The AT28C256-15UM/883 is rated for 10,000 write/erase cycles at its full operating temperature range of –55°C to +125°C, as specified in Section 4.3 (DC Characteristics) and validated per MIL-STD-883 Method 1032. This endurance level is maintained across the entire temperature envelope and is not derated for high-temperature operation.
AT28C256-15UM/883 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 FAQ
1.How can I place an order for AT28C256-15UM/883 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT28C256-15UM/883 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 reliable?
The price and inventory of AT28C256-15UM/883 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 is usually 5 days.
3.What payment methods are accepted for AT28C256-15UM/883?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT28C256-15UM/883 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT28C256-15UM/883?
AT28C256-15UM/883 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT28C256-15UM/883 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?
For technical support, including AT28C256-15UM/883 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT28C256-15UM/883 requirements.
6.How does Aetrix verify that AT28C256-15UM/883 is sourced from the original manufacturer or authorized distributors?
All AT28C256-15UM/883 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 meets industry standards.
7.What is the process for return or replacement of AT28C256-15UM/883?
All AT28C256-15UM/883 units undergo pre-shipment inspection (PSI). If there is an issue with AT28C256-15UM/883, 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 part is unused and in its original packaging.
Return procedure for AT28C256-15UM/883:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT28C256-15UM/883 Tags
-
M24C02-WMN6TP
STMicroelectronics
-
AT24C02C-XHM-T
Microchip Technology
-
AT21CS01-STUM10-T
Microchip Technology
-
AT24C02C-SSHM-T
Microchip Technology
-
24LC01BT-I/OT
Microchip Technology
-
M24C02-FMC6TG
STMicroelectronics
-
AT24CS02-SSHM-T
Microchip Technology
-
93LC46BT-I/OT
Microchip Technology
-
AT24C04C-SSHM-T
Microchip Technology
-
24LC01BT-I/SN
Microchip Technology
-
24AA02UIDT-I/OT
Microchip Technology
-
AT24C08C-STUM-T
Microchip Technology
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
