There is a difference. The power is different
8002A and 8002B and 8002 power amplifier ics are BTL bridged audio power amplifiers. It is capable of delivering less than 10% THD and an average output power of 3W to a 3Ω load at 5V supply voltage. The 8002B and 8002A series 3W Audio amplifier ics are suitable for portable audio products such as multimedia audio and SD card audio.
Personally, I think 8002B is better
The main difference between these two audio amplifiers is the difference in price and power.
The 8002a price is cheap and the power is small, while the 8002b price is more expensive and the power is large.