1. Saturation Voltage (Vce(sat)): The BC857BMB specifies 400 mV, while the BC857BLP4-7 is rated at 650 mV (both @ 5 mA, 100 mA). Under the same load current, the former offers lower conduction loss and higher efficiency, which is particularly critical in battery-powered or high-current applications. 2. Maximum Power Dissipation (Pmax): The BC857BMB is rated for 150 mW, compared to 250 mW for the BC857BLP4-7. The higher Pmax of the latter allows for either increased operating power or greater thermal design margin, making it suitable for high-ambient-temperature environments or applications subject to transient power surges. 3. Operating Temperature Range: The BC857BLP4-7 is explicitly specified for -55 °C to 150 °C, whereas the BC857BMB only lists a junction temperature of 150 °C. The former provides full industrial/automotive-grade temperature capability, offering superior reliability in low-temperature startup or extreme-environment applications. 4. Package and Process: Although both devices use DFN1006-type packages, the supplier-specific designations differ (DFN1006B-3 vs. X2-DFN1006-3). This suggests possible subtle differences in internal construction or pad layout, which could affect PCB thermal design or reflow soldering process windows. 5. Cost and Manufacturer: The BC857BLP4-7 carries a significantly higher price ($0.51 vs. $0.21). This cost difference stems from Diodes Incorporated’s process approach, test standards, or supply-chain channels, and should be weighed alongside considerations of supply stability.