TLC5947 Testing Attached LEDs

Lynn Klev

Other Parts Discussed in Thread: TLC5947

We will be doing incircuit test on boards with TLC5947 and LED banks. Can you tell me what the output gate characteristics are when the TLC5947 is powered off? In other words, if the board power is off, but we want to light up one of the LEDs to test it optically, would there be any current leakage into the TLC5947 output?

over 13 years ago

0 Brigitte over 13 years ago

TI__Guru 65340 points

Hello Lynn,

Please check the datasheet on page 4. The output leakage current with BLANK=high and 30V at the output is specified with maximum 0.1uA.

Best regards,
Brigitte

0 Lynn Klev over 13 years ago in reply to Brigitte

Prodigy 30 points

Hi Brigette, but VCC is off.

0 Brigitte over 13 years ago in reply to Lynn Klev

TI__Guru 65340 points

Hello Lynn,

If VCC is off, then it is not specified how much current is flowing into the output. I never tested it on this device, but I know that some parts start to supply themselves through the output if this is the highest voltage in the system. Is there a possibility to apply VCC during this test? Then you can be sure that everything works fine.

Best regards,
Brigitte

0 Lynn Klev over 13 years ago in reply to Brigitte

Prodigy 30 points

Hi Brigitte,

Yes, we'll keep VCC on to ensure we control the outputs. Thanks

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TLC5947 Testing Attached LEDs