December 13, 2017
GaN is a relatively new semiconductor technology, particularly in commercial applications. Due to GaN’s superior properties over incumbent technologies like LDMOS, it’s being used in more applications every day. Although engineers may assume that GaN is similar to LDMOS, it’s not.
This blog post and our brief tutorial video give you tips for how to bias GaN products for the best results.
GaN HEMTs are depletion mode devices, which means the device is normally on when the gate source voltage is zero. If you’re new to GaN, it's important to realize these two key points:
In contrast, LDMOS is an enhancement mode device and needs a positive, high drain voltage and a lower, positive gate voltage. For LDMOS, the gate voltage may be applied at the same time as drain voltage.
If you have experience with depletion mode FETs, you’ll see that GaN biasing is very similar. For GaN, the correct bias sequences for powering up and down are as follows:
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