TC1765_ds_v12 (TC1765_ds_v12_1202.pdf) - Infineon

Preliminary
Ports Power Supply
TC1765
The TC1765’s port power supply concept is shown in Figure 19. The External Bus Unit
(EBU) I/O lines are in the core and EBU V DD power supply group for 2.5 V nominal
operating voltage. The general purpose input/outputs (GPIOs) provide 3.3 to 5 V nominal
voltage input/output acceptance and drive characteristics.
V DD
(2.5 V)
EBU I/O Lines
(Pads)
&
Schmitt Trigger
Port Logic
Figure 19 Ports Power Supply Concept
V DDP
(3.3 - 5 V)
Ports 0 to 5
(Pads)
&
Schmitt Trigger
MCA05226
Power-up Sequence
During Power-up the reset pin PORST has to be held active until both power supply
voltages have reached at least their minimum values.
During the Power-up time (rising of the supply voltages from 0 to their regular operating
values) it has to be ensured, that the difference between VDDP and VDD never drops
below -0.5 V.
Power Loss
If VDDP is dropping below VDD, external circuitry in the power supply has to ensure, that
VDD is also limited to the same level.
If VDDI is dropping below the operating range, VDDP may stay active.
Powering Down
During powering down (falling of the supply voltages from their regular operating values
to zero), it has to be ensured, that the difference between VDDP and VDD never drops
below -0.5 V.
Data Sheet 54 V1.2, 2002-12
V SS