The 4051 chip can be replaced with 74HC4051 or CD4051.
Because 74HC4051 and CD4051 are programmable analog\/digital multiplexers, similar to the 4051 chip, and have a wider range of applications, higher performance and stability. In addition, if you need higher speed and lower power consumption, you can consider using the CD74HC4051E or 74HC4051D chip. In short, when choosing a replacement device, it is necessary to consider whether its parameters (such as voltage, speed, power consumption, package, etc.) meet the original design requirements, and do the relevant circuit design and testing work.
CD4051 is equivalent to a single-pole eight-throw switch, which switch is connected by the input 3-bit address code ABC to determine.