ATtiny13

The high-performance, low-power Microchip 8-bit AVR® RISC-based microcontroller combines 1 KB ISP Flash memory, 64B SRAM, 64B EEPROM, a 32B register file, and a 4-channel 10-bit A/D converter. The device supports a throughput of 20 MIPS at 20 MHz and operates between 2.7-5.5 volts. By executing powerful instructions in a single clock cycle, the device achieves throughputs approaching one MIPS per MHz, balancing power consumption and processing speed.

Also, see the picoPower® version: ATtiny13A.