1. Rated Current and Forward Voltage Characteristics The rated current of US2AA-TP (2A) is twice that of US1A-E3/61T (1A), and its Vf is specified at 2A, indicating lower conduction loss and better thermal design margin. If substitution is considered, the actual operating current must remain ≤1A with adequate derating margin; otherwise, overheating and failure may occur. 2. Junction Capacitance Difference The junction capacitance of US2AA-TP (28pF) is approximately 87% higher than that of US1A-E3/61T (15pF). In high‑frequency switching applications (e.g., >100kHz), this results in increased switching loss and higher EMI noise, potentially affecting power supply efficiency and signal integrity. 3. Leakage Current and Temperature Range US1A-E3/61T exhibits higher leakage current (10µA), which may slightly impact low‑power circuits. Its lower operating temperature extends to –55°C (compared to –50°C for US2AA‑TP), offering a marginal advantage in extreme low‑temperature environments, though this is negligible in typical applications. 4. Price and Brand Reliability Vishay components command a significantly higher price, generally reflecting tighter control over surge robustness, long‑term reliability, or consistency. Cost must be weighed against the application’s reliability requirements.