totowo
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Posts: 13
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The current limit of inductor is quite right. But the answer to jxbvt's primary puzzle, i think, is not this.
The inductor of output match is offchip because of its High Q. For example, if the on-chip inductor has a 3dB loss, that means half of the power is wasted. at input port, the input power is, e.g. 0dBm=1 mW, so the loss is only 0.5mW. It's receivability. while at output port, the output power is, e.g. 20dBm=100mW, so the loss on inductor is 50mW!!! It degrades the efficiency too much! Although the loss is 3dB too. Let's think in another way, the parasitic series res is, e.g. 100Ohm, when the current on inductor is 1mA, the loss is 0.1mW; while when the current on ind is 100mA, the loss is 1W!!!
In fact , the current limit of inductor is not the primary reason, for we can parallel several inductor to share the big current.
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