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QUICK START GUIDE

MEASUREMENT CONSIDERATIONS

The EPC9084 development board has been provided with

specially designed high frequency (up to 1 GHz minimum) capable

measurement connections using MMCX connectors located at J9 & J10

with direct access to the gate signals of both the upper and lower FETs.

These nodes can be measured directly using the Tektronix IsoVu probe

shown in figure 4. Figure 5 shows typical gate waveforms measured

using the IsoVu probe.

Figure 4: Tektronix IsoVu measurement setup

This native connection between the high and low side gate-source nodes

to an IsoVu probe tip cable has less than 2 pF common mode loading

and completely eliminates ground loops due to its galvanic isolation.

These MMCX connectors (option not installed) offer a shielded coaxial

environment to the test point which minimizes noise pickup.

EPC – EFFICIENT POWER CONVERSION CORPORATION |

Figure 5: Upper gate and lower gate measurements using the Tektronix IsoVu and

switch-node voltage measurement using the TPP1000 probe

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Please contact EPC for special instructions on using these connections.

To prevent an unterminated transmission line hanging on the gate it

is recommended to remove resistors R21 & R22 when not using this

feature. The maximum impedance loading of these nodes is 2.5 kΩ.

Tektronix is a leading manufacturer of power test solutions for design

validation, characterization, and performance testing. EPC partnered

with Tektronix to define the requirements for accurate measurements

on GaN devices which led to the development of the Tektronix IsoVu

measurement system. IsoVu is a galvanically isolated differential

measurement system with 1 GHz bandwidth, 1 Million to 1 (120 dB)

common mode rejection ratio, 50 V differential, and 2000 V common

mode voltage range. Previously impossible differential measurements

such as the high-side V

are now possible because of IsoVu's high

common mode rejection across bandwidth.

IsoVu allows you to:

• Characterize the time alignment of high side and low side events

• Optimize and tune switching characteristics such as edge rates,

overshoot, ringing and dead time

• See the interactions due to parasitic coupling between the high and

low side transistors

• Make isolated high frequency current measurements using low

impedance sense resistors

• Improve reliability through accurate characterization across all

operating conditions

EPC would like to acknowledge Tektronix

measurement-systems) for their support of this project.

EPC9084

(http://www.tek.com/isolated-

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