1. Current & Power Handling: The 2SC5824T100R offers an Ic of 3A and Pd of 2W, which are three times and twice those of the BCX5516TA, respectively. In applications operating near the original part’s limits (1A or 1W), the substitute provides greater margin. Nevertheless, the PCB thermal design must be checked to ensure it can handle the higher power dissipation potential. 2. DC Current Gain (hFE): The minimum hFE of the 2SC5824T100R (180) is notably higher than that of the BCX5516TA (100). For the same base current, this may result in a higher collector current. If the original circuit relies on specific gain linearity (e.g., in analog amplification), bias recalibration is necessary. For switching applications, the higher hFE is generally advantageous. 3. Frequency Response: The transition frequency is 200 MHz versus 150 MHz. While the difference is modest, the 2SC5824T100R may offer a slight edge in high‑frequency amplification (>100 MHz) or fast‑switching circuits. 4. Cut‑off Current (ICBO): The ICBO of the 2SC5824T100R (1 µA) is ten times higher than that of the BCX5516TA (100 nA). This may introduce minor leakage error in high‑temperature or high‑sensitivity low‑power circuits. 5. Temperature Range: The 2SC5824T100R does not specify a minimum operating temperature (only TJmax = 150°C), whereas the BCX5516TA is explicitly rated down to –65°C. For extreme low‑temperature environments, characterization of the substitute is advised. 6. Saturation Voltage Test Conditions: Both devices specify Vce(sat) = 500 mV. However, the 2SC5824T100R is tested under more demanding conditions (2 A / 200 mA) compared to the BCX5516TA (500 mA / 50 mA), indicating superior conduction characteristics at higher currents.