So I am interested in using some non inverting buffers.

Tell me if I am understanding this correct. The truth table of a buffer does nothing essentially. its 1 for 1

What I am interesting is the current source of the buffer. If I want to ensure whatever is driving my buffer , say a microcontroller, is not the thing sourcing the current to a load. a buffer is the answer right?

So my input current to the buffer should hopefully be micro amps? what is the parameter in the data sheet for this? There are so many parameters I'm not sure which is which. So the current coming out of the buffer is sourced from the VCC of the active buffer itself correct?
Also, what is the parameter showing how much current it can source? The names are confusing. If I have like an 8 pack buffer is there a max per chip?

Thanks in advance

 

If I want to ensure whatever is driving my buffer , say a microcontroller, is not the thing sourcing the current to a load. a buffer is the answer right?

Yes. The datasheet parameters yoy want are the 'Output low (sink) current' and the 'Output high (source) current'.

If I have like an 8 pack buffer is there a max per chip?

Yes.
The TI datasheet for CD4049 and CD4050 says:
'The recommended output condition for the CD4049UB application includes specific load currents. Load currents
must be limited so as to not exceed the total power (continuous current through VCC or GND) for the device.
These limits are in the Absolute Maximum Ratings.'

 

Thanks

I was looking at this chip and was confused because I don't see anything called output high source current

https://www.diodes.com/assets/Datasheets/74LV07A.pdf

 

I was looking at this chip and was confused because I don't see anything called output high source current

https://www.diodes.com/assets/Datasheets/74LV07A.pdf

That's because the device has an open drain output-- that is, it cannot source any output current, only sink. That's why the data sheet lists only "Low Level Output Current" and has no entry for "High Level Output Current."

 

That's because the device has an open drain output-- that is, it cannot source any output current, only sink. That's why the data sheet lists only "Low Level Output Current" and has no entry for "High Level Output Current."

Then why do they call it a line driver?

 

Also, with something like this

https://4donline.ihs.com/images/VipMasterIC/IC/QSEM/QSEMS00290/QSEMS00290-1.pdf

Why is the output current negative? It says -50mA max??

 

What kind of loads are you thinking of driving, and what kind of controller are you using. Some controllers have pretty hefty (by my standards) output drive capability.

 

What kind of loads are you thinking of driving, and what kind of controller are you using. Some controllers have pretty hefty (by my standards) output drive capability.

Nothing right now just learning.

I am more curious why the output current is negative

http://www.ti.com/lit/ds/symlink/sn74ac244.pdf

This one seems to be nice at 24mA output. However, Am curious still with the output current is negative.
Also still trying to figure out how to ascertain if all the pins are on, what can the output current be with everything on.
certainly not 24mA each with every pin on

 

Why is the output current negative? It says -50mA max??

The datasheet uses the convention that current into the IC is positive, current out is negative.

 

Then why do they call it a line driver?

I assume because it can sink a lot of current; most likely it's meant to drive lines that are terminated with resistors for impedance matching and good high-frequency performance.

I am more curious why the output current is negative

http://www.ti.com/lit/ds/symlink/sn74ac244.pdf

The usual convention in these data sheets is that sinking current is listed as a positive quantity and sourcing current is listed as a negative quantity.

 

Nothing right now just learning.

I am more curious why the output current is negative

http://www.ti.com/lit/ds/symlink/sn74ac244.pdf

This one seems to be nice at 24mA output. However, Am curious still with the output current is negative.
Also still trying to figure out how to ascertain if all the pins are on, what can the output current be with everything on.
certainly not 24mA each with every pin on

Output current is always negative if it flows out of the device. So if you have a load connected to ground (simplistically a resistor), and the output voltage is positive (say +2.5V), the current flow out of the driver and into the resistor is considered to be negative at the driver. This is a standard that does back to the early days of TTL.

 

Also still trying to figure out how to ascertain if all the pins are on, what can the output current be with everything on.
certainly not 24mA each with every pin on

That's given in the Absolute Maximum Ratings under "Continuous current through Vcc or Gnd" and is spec'd at ± 200 mA.

 

Why is the output current negative? It says -50mA max??

Some datasheets are more explicit about current direction than the one you referenced. If you read it, you can determine which direction is negative.


The line for \(V_{OH}\) says the HIGH output voltage at -24mA will be at least 2.4V. Obviously this has to be current out of the output.

TI has a glossary of terms and their definitions in their TTL databook (1982):

Note the note at the bottom.