This document describes a high-performance, low-power AVR® 8-bit microcontroller with advanced RISC architecture and various special features, including timers/counters, watchdog timer, analog comparator, ADC, universal serial interface, etc. The microcontroller also has programmable program and data memories, as well as various low-power modes and security features. This product is suitable for a wide range of applications.
The ATtiny43U is a low‑power CMOS 8‑bit microcontroller based on Atmel's enhanced AVR RISC architecture. It offers 4 KB of in‑system programmable flash, 64 bytes EEPROM, 256 bytes SRAM, 32 general‑purpose working registers, two 8‑bit timer/counters with PWM, a 10‑bit ADC, and a built‑in boost converter that supplies 3 V from low input voltages.
The device is available in 20‑pin SOIC and QFN/MLF packages with 16 I/O lines. It supports multiple power‑saving modes, including idle, power‑down (150 nA at 3 V) and ADC noise‑reduction. Programming is performed via SPI using In‑System Programming, and the part includes debugWIRE on‑chip debugging.
The datasheet details the CPU core, ALU, status register, interrupt architecture, and peripheral characteristics, as well as packaging, ordering, and errata information.
| Flash Memory | 4 KB |
|---|---|
| EEPROM | 64 bytes |
| SRAM | 256 bytes |
| General‑purpose Registers | 32 × 8‑bit |
| Timer/Counters | 2 × 8‑bit with PWM |
| ADC | 10‑bit, 4 single‑ended channels |
| Operating Voltage (Boost) | 0.7 V – 1.8 V |
| Operating Voltage (No Boost) | 1.8 V – 5.5 V |
| Maximum Clock Frequency | 0‑4 MHz @1.8‑5.5 V, 0‑8 MHz @2.7‑5.5 V |
| Active‑Mode Current (1 MHz) | 400 pA @3 V |
| Power‑Down Current | 150 nA @3 V |
| Write/Erase Cycles | 10,000 Flash / 100,000 EEPROM |
| Data Retention | 20 years at 85 °C, 100 years at 25 °C |
The ATtiny43U operates from 0.7 V to 1.8 V using the on‑chip boost converter, or from 1.8 V to 5.5 V when the boost converter is bypassed.
It provides 4 KB of in‑system programmable flash memory.
In power‑down mode the device draws 150 nA at 3 V.