SN74LVC1G125: SN74LVC1G125 comments in the absolute rating table

Zhizhao Niu

Part Number: SN74LVC1G125

Hi Team,

Could you please help to check what does this comment mean:

(2) The input and output negative-voltage rating may be exceeded if the input and output current ratings are observed.

I want to known if this requirement relax is only valid for MIN(-0.5V) which could be even lower than -0.5V if the current is very small, like 0.1mA.
For MAX +6.5V limit, can we use higher voltage Vinput more than 6.5 V connect to component but with very small current, like 0.1mA.

Thanks.

Zhizhao

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 243080 points

LVC inputs have a clamping diode from GND to the pin, but no diode to V_CC. (See [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)?)

When the input voltage is above −0.5 V, not current flows through this diode. When the input voltage is lower, a current flows, and might burn out the diode unless it is limited to less than 50 mA. (Usually, you put a series resistor in front of the input.)

For positive voltages, the problem is not the current (without a diode, no current can flow) but the voltage itself; any voltage above 6.5 V can break down the gate isolation.

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SN74LVC1G125: SN74LVC1G125 comments in the absolute rating table