How to select a buffer for my circuit

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arr_baobao

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Hi all,

i need to add a buffer for SPI bus from MCU to mixer ic.
what are the parameter i should look into it when selecting a buffer?
 

Re: how to select a buffer for my circuit

Use
TMS320x281x
 

Re: how to select a buffer for my circuit

Hi,

i need to add a buffer for SPI bus from MCU to mixer ic.
what are the parameter i should look into it when selecting a buffer?
Click to expand...

You say "I need"....
Why do you need it? --> This are your requirements for the buffer.

Usually one does not need a buffer.
Maybe you are driving a lot of slaves(high capacitive load), then I recommend to divide the bus using a MUX. Maybe with additional drivers...maybe not.
Maybe you are driving long cables, then I recommend to use differential signalling, maybe using RS422/RS485 drivers and receivers.
Maybe you want to drive a high speed, low noise 19" backplane bus, then I recommend differential signalling using LVDS.

Klaus
 
i noticed that all 4 signal buffer came with control signals. can someone recommend one without the control signal. thanks.
 

Hi,

Don't talk in riddles --> give complete informations.

What "all 4 signal buffer" are you talking about?

Klaus
 

i mean quad buffer. they all come with control signal. do u know any without the control signal?
 

Hi,

Come on.
Give good informations ... then you will get good answers.

Klaus
 

Hi,

You didn't respond to my post#3.
This doesn't motivate me or others to give new assistance...

We still don't know why you want to use buffers, therefore we don't know if a '125 is suitable at all.

And I don't see what's the problem with the control signals.
For a prototype it may take a minute to solder 4 pins to GND.
For mass production...it takes 4 seconds to connect them in the schematic to GND.

What's the alternative?
* Ask a manufacturer to build a special 10 pin IC fir you with 4 buffers inside?
* use a 6 buffer IC .... and connect the 2 unused inputs to GND?
* or the same with an 8 bits wide buffer?
Use 4 single_logic buffer ICs and solder 20 pins instead of 14?

Tell us your ideas.

Klaus
 

For example,
i need this kind of buffer but without the control signal/output enable.
Click to expand...
Apart from the unclear requirements, why are you worrying about an unused control signal? If there's no simple non-inverting buffer available in the chosen logic family, you can use tri-state buffer (125), AND, OR, whatever.
 

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