Hi, JinChi,
Regarding the core clock frequency, it can reach up to 50MHz, but we do not specify the minimum clock frequency, in other words, I think the clock frequency can be any value as you want. We gave the spec of 130uA/MHz, generally, the power consumption is proportional to the clock frequency in a limited range of clock frequency, but for extreme clock frequency for example 1KHz, there is a minimum value, but we do not specify in data sheet.
Hope it can help you
BR
Xiangjun Rong