1. MCP40D18T-503E/LT Substitution Conclusion The conclusion is that direct substitution is not feasible. The discrepancies lie in the nominal resistance value (50kΩ vs. 10kΩ) and the temperature coefficient (150ppm/°C vs. 45ppm/°C). With a 50kΩ resistance, the current flowing through the potentiometer under the same voltage will drop to one-fifth of that in the original part. This directly impacts the voltage division ratio, signal attenuation level, or bias current setting, causing the circuit's functionality to deviate from the original design. Furthermore, the significantly higher temperature coefficient of 150ppm/°C makes its resistance over three times more sensitive to temperature variations compared to the original part. In applications with a wide operating temperature range, this will introduce greater resistance error, adversely affecting system accuracy and stability.