Microchip Technology AT28C64B-15PI

Overview

AT28C64B-15PI from Atmel is a 64 Kbit (8K × 8) parallel EEPROM with JEDEC-standard byte-wide pinout, 150 ns read access time, 10 ms page write cycle (standard), and single 5 V ±10% supply operation. It supports hardware/software data protection, DATA polling, and toggle-bit write completion detection for embedded control and configuration storage in industrial instrumentation.

For engineers reviewing the AT28C64B-15PI datasheet, AT28C64B-15PI pinout, AT28C64B-15PI application, or AT28C64B-15PI equivalent, key selection criteria include industrial temperature range (−40°C to +85°C), 64-byte page write capability, CMOS standby current (100 µA), and compatibility with static RAM-style bus interfacing without external timing components.

Technical Context

The AT28C64B-15PI implements a parallel-access EEPROM architecture with internal 64-byte page latches, enabling up to 64 bytes to be written in a single internal programming period. Address latching occurs on the falling edge of CE or WE, and data latching on the first rising edge - supporting seamless integration into microcontroller address/data buses.

Write completion is verified via dual methods: DATA polling (complement on I/O7 during write, true data after completion) and toggle-bit detection (I/O6 toggles until write ends). Hardware protection includes VCC sense (<3.8 V inhibits writes), 5 ms power-on delay, and noise filtering on WE/CE inputs.

Key Specifications

Pinout & Package

AT28C64B-15PI is supplied in a 28-lead plastic dual inline package (PDIP), 0.600" wide (package code P6), with JEDEC-standard byte-wide pinout and industrial temperature rating (−40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ST M28W640ECB90N1 and Microchip 25LC640-I/P, the AT28C64B-15PI offers native 5 V parallel compatibility, JEDEC pinout, and deterministic 150 ns read timing - making it optimal for retrofitting legacy 8-bit designs where bus timing and footprint are fixed.

Availability

AT28C64B-15PI is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control modules, medical infusion pump configuration storage, and legacy embedded firmware patching requiring stable component supply across extended product lifecycles.

Supply support for AT28C64B-15PI 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 semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs.

The AT28C64B product line delivers parallel EEPROMs optimized for direct replacement of EPROMs and SRAMs in 8-bit embedded systems, emphasizing industrial reliability, pin compatibility, and simplified firmware update workflows.

FAQ

What is the maximum operating temperature range for the AT28C64B-15PI?

The AT28C64B-15PI is rated for industrial temperature operation from −40°C to +85°C. This specification is confirmed in the "DC and AC Operating Range" table of the official datasheet (Rev. 0270I–PEEPR–08/03), and applies specifically to part numbers ending in 'I' such as AT28C64B-15PI. Its packaging and process ensure stable read/write performance across this full range without derating.

Does the AT28C64B-15PI support page write operations, and what is the maximum page size?

Yes, the AT28C64B-15PI supports page write operations with a maximum page size of 64 bytes. As documented in the "Features" and "Device Operation" sections, the internal 64-byte page register allows sequential loading of 1–64 bytes within 150 µs intervals, followed by automatic internal programming. The page boundary is defined by address bits A6–A12, and all bytes in a single page write must reside on the same page.

How does hardware data protection work on the AT28C64B-15PI?

Hardware data protection on the AT28C64B-15PI operates through four mechanisms: (1) VCC sense - write inhibited if supply drops below ~3.8 V; (2) 5 ms power-on delay before write enable; (3) write inhibit when OE is low, CE is high, or WE is high; and (4) 15 ns noise filter on WE/CE inputs. These features are intrinsic to the AT28C64B-15PI silicon and require no software configuration.

Can the AT28C64B-15PI be used as a direct replacement for the AT28C64B-15PC in an existing design?

Yes, the AT28C64B-15PI can replace the AT28C64B-15PC in most cases because both share identical electrical specifications, pinout, and timing - differing only in temperature grade (industrial vs. commercial) and package (PDIP for both). The AT28C64B-15PI's −40°C to +85°C rating extends operational margin, and no PCB or firmware changes are needed unless the original design relied exclusively on commercial-grade validation.

What methods are available to detect write completion on the AT28C64B-15PI?

The AT28C64B-15PI provides two independent, hardware-supported methods: DATA polling (monitor complement on I/O7 until true data appears) and toggle-bit detection (observe toggling on I/O6 until it stabilizes). Both methods are functional during any write cycle - byte or page - and require no additional hardware. The AT28C64B-15PI datasheet confirms these are implemented in silicon and do not rely on external timing assumptions.