Yutao Liu
Community Member
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Posts: 76
Guangzhou, China
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Hello, The source switching charge pump post above is attractive due to its less current consumption. I try to design this charge pump. But its switching speed is not so high as current-steering counterpart. In my case, Icp in DC simulation is 300uA, the bias current is 30uA. And the reset pulse from PFD is 2ns. I ran transient simulation with no phase error between clk_ref and clk_fb. The current flowing out from M2's drain did not reach 300uA within 2ns, but about 260uA. But the voltage at M2's source is lift to Vdd as soon as UP is low. The same situation happened to NMOS counterpart. why did it take so long for the current source(M2) to reach its steady value?
Best Regards, Yutao
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