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Shar , 12-31-2024, 11:59 AM

H ow do we decide when we have to use buffers in our hardware design...I was referring to some reference designs and saw for some signals from one IC to another... buffers are used.....
One what basis it is decided beforehand for hardware design.......

And suppose I am using a buffer IC....and it's supply is Vcc...is it necessary that the input signal logic level has to be lower than Vcc...? If not ...then what is the reason....

Just a doubt from a fresh graduate beginning career in hardware design....

Sanam , 12-31-2024, 01:01 PM

Buffers are used when the drive strength of the driver is low, that is it can only provide low current. If you draw more current from it, then its voltage will also drop. So a 5V signal may become 4.75V or lower to accomodate this higher current. Microcontroller pins have a rated current source and sink limit mentioned. If you want to go higher then that, then you use a buffer.

The buffer IC you use should mention the voltage levels it can support and needs in the datasheet. Usually buffers also have the same voltage swing as that of the source and load IC.

Hope that clears your doubt.

Robert Feranec , 01-02-2025, 09:34 AM

there are number of reasons why buffers are used. as @Sanam mentioned, one reason may be current requirements, but you can have voltage translators (e.g. if you need to connect circuits with different voltages), sometimes you may need to change the type eg. push pull to open drain, sometimes you would like to make the signal stronger before it goes out of your board or use it as a protection (e.g. some buffers may have better ESD) or you need hysteresys (schmitt) or you may need HighZ output .... many different posibilities