Sleep Current Arithmetic behind a Five Year Battery Claim
Five-year battery claims require balancing microampere sleep floors, primary cell passivation derating, and protocol airtimes across 43,800 hours.
CMOS Shoot-through Current
Meaning
Transient conduction occurs in digital logic circuits when both the high-side and low-side transistors are partially turned on at the same time during a state transition. This cmos shoot-through current creates a direct path from the power supply to ground, leading to brief power spikes. Minimizing this effect is necessary to control thermal dissipation in high-frequency designs.
Switching Mechanism
During a logic transition, the input signal moves through the intermediate voltage region where both the p-channel and n-channel transistors conduct. This overlapping conduction causes the cmos shoot-through current to flow, with its magnitude determined by the transition speed of the input signal. Slow rise and fall times prolong the duration of this overlap, resulting in higher average power consumption.
Mitigation Strategy
Introducing a dead-time delay between switching events prevents the simultaneous activation of both transistors. This design step effectively eliminates cmos shoot-through current in driver circuits.
Thermal Consequence
Operational speed increases the frequency of transition events, making transient losses a major contributor to the overall energy budget. In high-frequency systems, cmos shoot-through current occurs millions of times per second, which raises the temperature of the silicon. This thermal load can degrade the long-term reliability of the integrated circuit if the thermal layout is inadequate.