Articles by Eric Bogatin

Life at the Low End

We usually associate problems with the power distribution network (PDN) as from excess VRM noise, or from transient current draw from the core or I/O drivers. But that’s not the only source of PDN noise. Some failures can arise from dull, boring, mundane problems at DC.


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Why On-Die Power-Rail Measurements are Important

For this project, we will use an Atmel 328 microcontroller demo board, prepared with firmware to control it explicitly for our purposes, and with coaxial cables connected between the I/O pins and the input to the active probes of the scope. This interconnect provides a high bandwidth transmission line path for the signals.


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Bandwidth, Current Load and Power-Rail Measurements

How do you achieve high bandwidth in your measurements while minimizing current load on your DUT? Given that your DUT is a power rail, you really don't want to draw too much current from it., or your measurement system will distort the rail. But these two measurement criteria are at loggerheads with each other. It's a quandary, and it has to do with the fundamental nature of signals on interconnects.


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Mitigate RF Pickup In Power Rails

Measuring the noise on a power rail seems to be a straightforward task. However, there are some basic pitfalls that can cause incorrect, or even downright strange, results. Let's look at one of these challenges: RF pickup. We'll demonstrate the effect of RF pickup on a power-rail measurement, and then we'll show you an effective means of mitigating that effect.


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Validating IBIS Models with Measurements

At the University of Colorado, Eric Bogatin and students Thomas Rutkowski and Huy Nguyen look for a way to validate IBIS models, bringing measured data from a scope into a simulation environment. This article includes an explanation of how the team compared predicted results of the IBIS model supplied by the vendor, the results from a generic model, and measured results from a randomly selected part.


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A Design Rule Check List

No matter how well you understand the design principles, and no matter how much experience you have in designing boards, it’s easy for some problems to slip through the cracks because you just forgot to check that feature, or your design is just too big to manually check. This is where a design rule checker comes in.


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