SN74AXC8T245: How to deal with the unused Pin

Hao Wang14

Part Number: SN74AXC8T245

Hi Team,

We designed a circuit shown in the picture:

1. The maximum data rate from B1 and B2 is 125MHz, can it have such high data rate?

2. What should we do with the unused pins? Should they be left float or grounded? If grounded, should they connect with ground directly or through a resistor?

Thanks

Hao

over 7 years ago

0 Karan Kotadia over 7 years ago

TI__Genius 16735 points

Hello Hao,

1. B1 and B2 can support this data rate. They are spec'd for a data rate of 190 MHz so 125Mhz should not be a problem.

2. All unused data inputs of the device must be held at VCCI or GND to ensure proper device operation. They can be tied directly to GND. See the Implications of Slow or Floating CMOS Inputs application report to learn more. www.ti.com/.../scba004d.pdf

Thanks!
- Karan

0 Hao Wang14 over 7 years ago in reply to Karan Kotadia

TI__Expert 4415 points

Hi Karan,

Thanks! Can we tie the unused pins to ground through a 0 ohms resistor? Will there be any bad effect with 0 ohms resistor?

Best Regards,
Hao

0 Karan Kotadia over 7 years ago in reply to Hao Wang14

TI__Genius 16735 points

Hello Hao,

You can ground the unused pins through a 0 Ohms resistor. There will be no adverse effects.

Thanks!
- Karan

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SN74AXC8T245: How to deal with the unused Pin