The sp1602 chip and the 3842 chip are both switching power supply chips, but their functions and performance parameters are not exactly the same, so they cannot be directly replaced. If you need to replace the sp1602 chip, you need to consider the functions, performance parameters, and package type of the chip, and select and adjust the chip based on the actual situation.
You are advised to consult relevant technical documents and materials, or consult professional technical personnel for more detailed information and guidance.