| Part Number | AT89LS51-16AU | AT89LS51-16PU | 
|---|---|---|
| Manufacturer | Microchip Technology | Microchip Technology | 
| Category | Embedded - Microcontrollers | Embedded - Microcontrollers | 
|   |   | |
| Product Status | Active | Active | 
| Core Processor | 8051 | 8051 | 
| Core Size | 8-Bit | 8-Bit | 
| Speed | 16MHz | 16MHz | 
| Connectivity | UART/USART | UART/USART | 
| Peripherals | WDT | WDT | 
| Number of I/O | 32 | 32 | 
| Program Memory Size | 4KB (4K x 8) | 4KB (4K x 8) | 
| Program Memory Type | Flash | Flash | 
| EEPROM Size | - | - | 
| RAM Size | 128 x 8 | 128 x 8 | 
| Voltage - Supply (Vcc/Vdd) | 2.7V ~ 4V | 2.7V ~ 4V | 
| Data Converters | - | - | 
| Oscillator Type | Internal | Internal | 
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) | 
| Mounting Type | Surface Mount | Through Hole | 
| Package / Case | 44-TQFP | 40-DIP (0.600", 15.24mm) | 
| Supplier Device Package | 44-TQFP (10x10) | 40-PDIP |