questions about the current ability of the pin of TMS570LS31737

Jiaming Sun

Other Parts Discussed in Thread: TMS570LS3137

Hi,all

I use some pins of TMS570LS3137 to light the LED ,but from datasheet ,some pins only can sustain 2mA or 4mA current? If I use this small current ,the LED is not light enough. Can these pins bear larger current?

over 11 years ago

0 Praveen Kumar Ravichandran over 11 years ago

TI__Expert 4610 points

Hi,

Thanks for using E2E forum. We have recieved your query, we shall get back to you at the earliest possible.

Regards,
Praveen

0 Praveen Kumar Ravichandran over 11 years ago in reply to Praveen Kumar Ravichandran

TI__Expert 4610 points

Hi,

As given in the spns162b, table 3-2 shows the output drive strength of each pin. It cannot drive more than that. As you can see, some signals have selectable 2/8mA current.

Regards,
Praveen

0 Jiaming Sun over 11 years ago in reply to Praveen Kumar Ravichandran

Expert 1300 points

If I connect the pin of TMS570LS3137 to the LED ,and the other end of LED connect to VCC , can the pin sustain more current than the output driver ability?

0 Harshit Jain84300 over 11 years ago in reply to Jiaming Sun

TI__Prodigy 80 points

Jiaming,

If you connect TMS570LS3137 I/O pin to one end of an led and other to VCC, please put a current limiting resistor in between(value of resistor depends on the forward voltage drop of the LED chosen). Also, LED will not sustain more current in the sink(input) state.

Still if you want more brightness, then use a transistor to sink in more current through the LED, attaching the picture. Here the gate/base of the transistor is driven by the microcontroller I/O to control the LED on/off. Hope this helps.

Regards,

Harshit

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questions about the current ability of the pin of TMS570LS31737