74hc595 current cappabilty

[thannara123]

how much current can be drawn from it ?
can i drive 8x8 LED matrix directly without ULN (or LED drivers )
please help me how can i calculate the values for driving the 8x8 LED matrix
thanking you

 

[shamikrudra]

it can drive 70mA. check the data sheet. without uln or led driver you can drive these 8x8. I have used it with 74 series IC working great.

 

[alexan_e]

it can drive 70mA. check the data sheet. without uln or led driver you can drive these 8x8. I have used it with 74 series IC working great.

No it can't.
70mA is the MAX (total) supply current.
For the outputs there is a MAX specification of +-35mA (Qn) but the operating specification give a voltage drop in the output of about 1v with just 5mA so if you intend to use more than that you have to use an additional driver device.

Alex

 

[thannara123]

please tell me the available drivers for driving LED matrix /

 

[alexan_e]

ULN2003 for cathodes
ULN2981 for anodes.

or you can use discrete transistors

Alex

 

[thannara123]

how can i correctly calculate 8x8 led matrix current ?
how much current will draw each LED ?
i don't know how calculate it ?
10MA x 8 Led = 80MA
if so
then how the voltage ? or what is the voltage comes from the 74hc595 ?

 

[FvM]

There's a huge number of previous threads discussing suitable LED matrix circuits and their calculation.
See e.g. https://www.edaboard.com/threads/218991/ Much more refrences can be found when searching the board intensively.

The required current capability of row and column drivers is different by a factor of eight, which is usually considered when selecting the hardware.