SN74LVC1G07: Use SN74LVC1G07 as driver, but no output from device

Oliver Lin

Part Number: SN74LVC1G07
Other Parts Discussed in Thread: CSD16301Q2, SN74LVC1T45

Hi team,

My customer is using SN74LVC1G07 for level shifter and external pull to drive an MOSFET CSD16301Q2. Does this circuit have any problem or not? Customer input 20MHz signal into the device, but no output is found

Thanks,

Oliver

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 243910 points

Assuming that the gate is a 300 pF capacitor, charging it through a 10 kΩ resistor would be done with a time constant of 3 µs. This is much too slow for 20 MHz.

You would need a device with a push/pull output, e.g., SN74LVC1T45. And then the charge/discharge current would likely exceed the absolute maximum rating, so you would need a series resistor (5 V / 50 mA = 100 Ω).

And why 20 MHz and not 200 kHz?

0 Oliver Lin over 3 years ago in reply to Clemens Ladisch

TI__Intellectual 2945 points

Hi Clemens,

Thank you for your suggestion, 20MHz is coming from customer spec.

May I know the series resistor shall be placed in series between what components?

0 Dylan Hubbard over 3 years ago in reply to Oliver Lin

TI__Mastermind 42640 points

Hey Oliver,

If they switch to a device with a push pull output like the one Clemens suggested, then they would need to add the series resistor at the output of that device.

Logic

Logic forum

SN74LVC1G07: Use SN74LVC1G07 as driver, but no output from device