# AT28HC64B: 64K EEPROM

## Product Overview
* 64K (8K x 8) EEPROM
* High-speed parallel interface
* Page Write and Software Data Protection features
* Industrial Temperature Range

## Features
* **Fast Read Access Time:** 70 ns
* **Automatic Page Write:** Internal address and data latches for 64 bytes.
* **Page Write Cycle Time:** 10 ms (Standard), 2 ms (Option).
Up to 64 bytes written simultaneously.
* **Low Power Consumption:** 40 mA Active, 100 µA CMOS Standby.
* **Data Protection:** Hardware and software mechanisms against inadvertent writes.
* **End of Write Detection:** DATA Polling and Toggle Bit.
* **High Reliability:** 100,000 Cycles Endurance, 10 Years Data Retention
* **Supply Voltage:** Single 5 V ±10%
* **Compatibility:** CMOS and TTL compatible inputs and outputs
* **Pinout:** JEDEC approved byte-wide
* **Device Identification:** Extra 64 bytes for user identification

## Operation
* **AC Read Characteristics:** See AC Read Waveforms (AT28HC64B-70, -90, -120 variations exist).
* **Data Polling:** I/O7 presents the complement of the last written data during the write cycle.
* **Toggle Bit:** I/O6 toggles during write cycles, stops toggling when complete.
* **Software Data Protection (SDP):** Enabled/disabled by a 3-byte command sequence.
Protects against inadvertent writes.
* **Device Identification:** Addresses 1FC0H to 1FFFH for user-defined data.

## Package Options
* Refer to datasheet for available package types.