The only difference in specifications between the probe hardware
(PHX400, PHX401, PHX403) is the target operating voltage range.
| Model | Target Operating Voltage Range |
| PHX400 | 2.0 ～ 5.0V |
| PHX401 | 1.7 ～ 3.3V |
| PHX403 | 1.7 ～ 5.0V |
The probe hardware (PHX40x) uses a mechanism that allows it
to interface with the target using the target power supply voltage
input to the TVcc.
Example:
If a voltage of 3.3V is input to the TVcc, the serial communication
input/output voltage will be 3.3V. (The output voltage of the output
terminals (TTXD, TCK, TAUX, etc.) will be 3.3V.)
*The TVcc input voltage is used to amplify the current using
an operational amplifier, which powers the buffer IC in the
output stage of the PHX40x.
Due to the high input impedance of the TVcc, current
consumption from the target is minimal. (Max 300uA)