Tell me about the input tolerant function.
Input/output equivalent circuit and specifications of input/output allowable voltage are shown below:
The input tolerant function is a function to prevent current from input to the power supply when the input is set higher than the power supply voltage or when power supply VCC = 0V.
The specification of the allowable input voltage is described in the input voltage of recommended operating conditions. When input/output specification is 0 - VCC, voltage that exceeds VCC cannot be applied because the circuit has a diode.
The input voltage of VHC/LCX is 0 - 5.5V (with input tolerant function), so voltage up to 5.5V can be applied to input regardless of the power supply voltage. When the power supply voltage VCC = 3.3V, level conversion from 5V to 3.3V is available.
The input voltage of VCX is 0 - 3.6V (with input tolerant function), so voltage up to 3.6V can be applied to input regardless of the power supply voltage. When the power supply voltage VCC = 1.8V, level conversion from 3.3V to 1.8V is available.
| tolerant function | Both input/output | input only | Neither input/output | |
|---|---|---|---|---|
| series | VHCT，LCX，VCX | VHC，LVX | AC/ACT，HC/HCT | |
input/output equivalent circuit |
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| allowable input voltage | operating | 0 - 5.5V (VCX 3.6V) | 0 - 5.5V (VCX 3.6V) | 0 - VCC |
| Power down | 0 - 5.5V (VCX 3.6V) | 0 - 5.5V (VCX 3.6V) | 0V (voltage cannot be supplied) | |
| allowable output voltage | output enable | 0 - VCC | 0 - VCC | 0 - VCC |
| output disable | 0 - 5.5V (VCX 3.6V) | 0 - VCC | 0 - VCC | |
| Power down | 0 - 5.5V (VCX 3.6V) | 0V (voltage cannot be supplied) | 0V (voltage cannot be supplied) | |
| Item | Symbol (Unit) |
Rating | Remarks | ||
|---|---|---|---|---|---|
| TC74VHC | TC74LCX | TC74VCX | |||
| Power supply voltage | VCC (V) |
2 - 5.5 | 2 - 3.6 | 1.65 - 3.6 | |
| Input voltage | VIN (V) |
0 - 5.5 | 0 - 5.5 | 0 - 3.6 | With input tolerant function |
| Output voltage | VOUT (V) |
0 - VCC | 0 - 5.5 (Note 1) |
0 - 3.6 (Note 1) |
LCX and VCX: with output tolerant function |
| 0 - VCCA (Note 2) |
0 - VCCA (Note 2) |
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- Note 1: output HZ
- Note 2: output "H" or "L"
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