SN74LVC1G123: Make LED Light stay on for a 100ms after trigger rising or falling edge

d_zero

Genius 4775 points

Part Number: SN74LVC1G123

Dear *,

we want to give a LED a fade-out is the SN74LVC1G123 a good choice?

Can we direct drive the led from the output of SN74LVC1G123? or do we need a mosfet?

Is it ok to use 10k and 10uF for 100ms ?

Best Regards,

David.

0 Clemens Ladisch over 4 years ago

Guru 316510 points

LVC outputs can easily drive 20 mA.

Figures 4 and 5 of the datasheet show how to achieve 100 ms.

0 d_zero over 4 years ago in reply to Clemens Ladisch

Genius 4775 points

Dear Clemens,

please can you check the schematic below and tell:

1) is it better to connect the input on CLR or B base don table 1. in DS ?

2) do we need pull-up or pull-down, on the input that are fixed level?

3) do we need pull-down on Q output and on CLR or B input when this input is used for triggering?

Best Regards,

David.

0 Dylan Hubbard over 4 years ago in reply to d_zero

Hey David,

1. I'd recommend using B as the input.

2. Pull-ups/pull-downs aren't needed for those.

3. Q won't need a pull-down. If the input is expected to be floating at any point, then a pull-down should be used.

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