IoT Semiconductor Ultra-Low Power is semiconductor devices consuming microwatts enabling battery operation for years in wireless sensors and edge devices — power is critical constraint. Energy Harvesting devices powered by ambient energy (solar, RF, vibration, thermal). Reduce battery dependence. Sleep Modes most of time in sleep (microamps). Wake periodically (milliseconds awake). Duty Cycle 0.1-1% duty cycle typical: sleep 99%, active 1%. Power Consumption Hierarchy CPU >> RF >> sensors >> memory. Optimization focuses on heaviest consumers. Processor Selection ARM Cortex-M0+ (ultra-low power), Cortex-M3/M4. MHz-range speeds adequate. RF Module Bluetooth Low Energy (BLE), LoRaWAN, ZigBee. Optimized for low power. Idle current microamps. Sleep Current Leakage semiconductor leakage in sleep; total power (active + sleep). Leakage increasingly important. Wakeup Latency transitioning from sleep to active takes time/energy. Balance wake speed vs. sleep depth. Memory SRAM power critical; FLASH non-volatile but slower. Sensor Power sensors themselves consume power (always-on accelerometer for activity detection vs. sleeping accelerometer). Wireless Protocol shorter packets, less frequent transmission reduce power. Battery Technology alkaline AAs typical; rechargeable (Li-ion) for harsh environments. Battery Voltage decreasing supply voltage (2.7V down from 3.3V); regulators less efficient. Transducer Efficiency data transmission most power-expensive. Compression, filtering reduce. RF Power RF transmit dominates. Higher power for range; lower for local. Network mesh networking extends range via relays. Cloud edge computing: process locally, send only results. Wake Sensors passive infrared (PIR) triggers wake; ultra-low power. Accelerometers MEMS accelerometer detects motion; wakes device. Time-to-Live system lifetime (battery + harvesting) years to decades. Lifetime Prediction Weibull analysis estimates reliability. Product Examples fitness trackers, environmental sensors, door locks, security tags. Emerging millimeter-scale devices (motes). IoT semiconductors enable ubiquitous computing through ultra-low power design.