| Part Number | AT28HC256-90PI | AT28HC256-90SI | 
|---|---|---|
| Manufacturer | Microchip Technology | Microchip Technology | 
| Category | Memory | Memory | 
|   |   | |
| Product Status | Obsolete | Obsolete | 
| Memory Type | Non-Volatile | Non-Volatile | 
| Memory Format | EEPROM | EEPROM | 
| Technology | EEPROM | EEPROM | 
| Memory Size | 256Kb (32K x 8) | 256Kb (32K x 8) | 
| Memory Interface | Parallel | Parallel | 
| Clock Frequency | - | - | 
| Write Cycle Time - Word, Page | 10ms | 10ms | 
| Access Time | 90 ns | 90 ns | 
| Voltage - Supply | 4.5V ~ 5.5V | 4.5V ~ 5.5V | 
| Operating Temperature | -40°C ~ 85°C (TC) | -40°C ~ 85°C (TC) | 
| Mounting Type | Through Hole | Surface Mount | 
| Package / Case | 28-DIP (0.600", 15.24mm) | 28-SOIC (0.295", 7.50mm Width) | 
| Supplier Device Package | 28-PDIP | 28-SOIC |