Key Digital ES381 - Manual (Page 16)

2.4 Input Control
2.4.1 Input Supply
The USBcount50 supports a programmable input supply via the
slider control.
Supplies from 1.50V to 5.00V are possible, and the slider control
adjusts in 256 steps of 13.67mV per step. This range allows the user
to match against common industry standard logic levels present in
their circuit to be measured
6
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Elan Digital Systems Ltd. 16 USBcount50 USER’S GUIDE Iss1
6 Note that the input switching threshold is not a linear function of the supply voltage, rather the
threshold varies in steps as the supply voltage is increased, corresponding to the Vih specifications for
1.8V, 2.5V, 3.0V, 3.3V and 5.0V logic domains.