Power Integrity

RSS

There are many questions about measuring Power Delivery Networks (PDN), but these two are very common ones.  Why do we calibrate the 2-port measurement with a 1Ω shunt resistor and why do I use DC blockers on both ports?  In this article I’ll provide responses to both of these questions.  The measurement setup in Figure 1 is an example where I used both the 1Ω calibration and the inclusion of the DC blockers.

As systems designers work hard to squeeze more and more features into less board space, the power delivery paths are becoming increasingly complex. The current mature VRM designs based on Silicon MOSFETs are hardly meeting present day requirements. One of the promising technologies touted to solve this conundrum of space and performance constraints is GaN HEMT. However, many engineers are hesitant to design very high frequency GaN VRMs from the ground up. This paper evaluates the steps required to modify existing Si-MOSFET designs for use with eGaN HEMT devices. The paper also compares the expected performance of GaN vs. Si in linear and switching regulator topologies and covers some of the measurement challenges as well.