Microchip Technology AT28C64-12PC

Overview

AT28C64-12PC from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with 120 ns read access time, self-timed byte write cycle, and JEDEC-standard 28-pin PDIP package. It operates at 5V ±10%, supports CMOS/TTL I/O compatibility, and delivers 30 mA active current and 100 µA standby current for embedded microcontroller systems requiring nonvolatile storage with direct bus interfacing.

For engineers reviewing the AT28C64-12PC datasheet, AT28C64-12PC pinout, AT28C64-12PC application, or AT28C64-12PC equivalent, key selection criteria include its 120 ns read timing, 1 ms standard byte write, RDY/BUSY and DATA polling write completion detection, 10⁴ write endurance, and industrial-grade temperature range support in PDIP packaging.

Technical Context

The AT28C64-12PC functions as a drop-in parallel memory replacement for SRAM in microprocessor systems, using CE/OE/WE control logic identical to static RAM. Its internal address and data latches free the bus during self-timed writes, while the RDY/BUSY open-drain output and I/O7 data polling provide deterministic write-cycle termination signaling.

It implements VCC sense (write inhibit below 3.8 V), 5 ms power-on delay, and triple-level write inhibition (OE high, CE high, or WE high) for robust inadvertent-write protection. The device includes 32 bytes of dedicated identification EEPROM accessible via A9 = 12 V and addresses 1FE0H–1FFFH.

Key Specifications

Pinout & Package

AT28C64-12PC uses a 28-lead, 0.600" wide plastic DIP (PDIP) package per JEDEC MS-011 AB, with pin 1 designated as RDY/BUSY (open-drain) and pins 15–17 assigned to I/O0–I/O2.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar parallel EEPROM applications.

Compared with AT28C64-12PC, AT28C64B-12PC offers superior data retention and tighter timing guarantees for mission-critical storage, while MX28LV640C-12PC provides second-source availability at the cost of added 12 V circuitry and loss of hardware-ready signaling.

Availability

AT28C64-12PC is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and test equipment requiring stable component supply with long-lifecycle support and traceable sourcing.

Supply support for AT28C64-12PC 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) is a fabless semiconductor company specializing in microcontrollers, nonvolatile memory, and secure authentication ICs.

The AT28C64 product line was designed to replace UV-erasable EPROMs and battery-backed SRAM in 8-bit embedded systems, delivering electrically erasable, byte-alterable storage with SRAM-like interface simplicity.

FAQ

What is the maximum operating temperature range for the AT28C64-12PC?

The AT28C64-12PC is rated for commercial temperature operation from 0°C to +70°C. This range is explicitly defined in the ordering information table for the "-12PC" suffix, where "C" denotes Commercial grade. Industrial variants (e.g., AT28C64-12PI) extend to –40°C to +85°C, but the -12PC variant does not support that extended range.

Does the AT28C64-12PC require a 12 V supply for normal operation?

No, the AT28C64-12PC operates solely from a 5 V ±10% supply (VCC). A 12 V supply is required only for two special operations: Chip Erase (applied to OE) and Device Identification (applied to A9). These are infrequent, factory or service-level functions-not part of routine read/write cycles. Normal read and byte write use only 5 V.

How does write completion detection work on the AT28C64-12PC?

The AT28C64-12PC supports two independent write completion detection methods: (1) RDY/BUSY pin (pin 1), an open-drain output pulled low during write and released high upon completion; and (2) DATA polling, where reading I/O7 returns the complement of the written data until completion, then returns true data. Both methods are fully supported on the AT28C64-12PC.

Is the AT28C64-12PC pin-compatible with standard 2764 EPROMs?

Yes-the AT28C64-12PC uses the JEDEC-approved byte-wide pinout identical to the 2764 EPROM (28-pin DIP), including matching A0–A12, I/O0–I/O7, CE, OE, and WE assignments. Pin 1 (RDY/BUSY) replaces the 2764's NC, but remains unused in EPROM-mode operation, enabling direct socket replacement without PCB modification.

What is the endurance rating of the AT28C64-12PC, and how is it verified?

The AT28C64-12PC is rated for 10,000 write/erase cycles (10⁴), as stated in the Features section and confirmed in the Absolute Maximum Ratings table. This endurance level is validated through accelerated life testing per JEDEC standards and applies across the full commercial temperature range. The "E" variant (e.g., AT28C64E) offers 100,000 cycles, but the standard AT28C64-12PC delivers 10⁴ cycles.