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PAC1934 Evaluation Board (ADM00805) User’s Guide

DS50002673A-page 30

 2017 Microchip Technology Inc.

FIGURE 4-2:

MEASURING THE VOLTAGE AND CURRENT ON THE VIO PIN

WITH CHANNEL 1

Please note that the GUI is not capable of capturing data points as fast as the PAC1934

is capable of producing them. For this reason, the fastest rate that data can be captured

and plotted is approximately one point per 250 samples when sampling at 1024 sam-

ples/second. Therefore, the true period variation of the un-averaged measurements

cannot be accurately seen with this GUI and appears more like noise.

A similar option is available in DEMO mode for measuring the VDD current required by

the PAC1934. The IDD current flows in R19 (10Ω). Move the shunts for J16 and J16 to

the VDD position to connect Channel 4 inputs across R19, and the GUI may be used to

display IDD as ISENSE on channel 4. In Figure 4-3 VDD is displayed as VBUS with chan-

nel 4 and IDD is displayed as Current on Channel 4.

FIGURE 4-3:

MEASURING THE VOLTAGE AND CURRENT ON THE VDD

PIN WITH CHANNEL 4

4.8

ADDITIONAL HARDWARE DETAILS

Directly above and below the PAC1934 are shorted jumpers labeled VIO (J22) and VDD

(J29). These provide a place for removing the short and inserting a current meter if the

user wishes to measure the current in the VDD_IO pin and/or the VDD pin.

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