TUSB564: 4-State CMOS Inputs Specification

Anderson2

Expert 1035 points

Part Number: TUSB564

Hi,

When a 4-State CMOS Input pin is open, its voltage is 0V not between 1.65V and 2.7V.

Is it correct working?

Would you tell me the internal equivalent circuit?

over 6 years ago

0 David (ASIC) Liu over 6 years ago

TI__Guru**** 177171 points

These 4-level inputs utilize a resistor divider to help set the 4 valid levels and provide a wider range of control settings. There is an internal 35 kΩ pullup and a 95 kΩ pull-down. These resistors, together with the external resistor connection combine to achieve the desired voltage level.

What is the VCC voltage? Can I take a look at the schematic?

Thanks
David

0 Undrea Fields over 6 years ago in reply to David (ASIC) Liu

TI__Genius 11000 points

In addition, these inputs are latched at power-up, after the inputs are latched, the internal pull-ups and pull-downs are isolated to conserve power.

0 Anderson2 over 6 years ago in reply to Undrea Fields

Expert 1035 points

Dear David, Undrea
Thank you.
In our schematic, The VCC and EN are 3.3V.
These inputs are always Low at steady state even if float, right?
If I 'd like to change the setting(ex. EQ, SSEQ or DPEQ), is it need to turn off the VCC and on?

0 David (ASIC) Liu over 6 years ago in reply to Anderson2

TI__Guru**** 177171 points

After you change the settings, besides toggling VCC, you can also toggle EN pin to sample these 4-level inputs.

Thanks
David

0 Anderson2 over 6 years ago in reply to David (ASIC) Liu

Expert 1035 points

Hi David
I could confirm 4-level inputs, Thank you.

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TUSB564: 4-State CMOS Inputs Specification