TUSB6250: Pullup Resistor on IORDY Pin

Shinichi Yokota

Part Number: TUSB6250

Hello,

The data sheet says in the section 13.4.3, "IORDY 1-kΩ pullup resistor should be implemented on the ATA/ATAPI host connector (TUSB6250 side)," while the schematic on "TUSB6250 Demonstration Board User's Guide" (SLLU045B) uses a 4.7-kΩ resistor (R94). Which is correct?

Best regards,
Shinichi Yokota

over 2 years ago

0 Nicholaus_Malone over 2 years ago

TI__Mastermind 27925 points

Hi Shinichi Yokota,

The datasheet should reflect the values given in the specification. "...it is recommended to implement pullup and pulldown resistors at the board level with the value defined by the ATA/ATAPI-5 specification."

I see the recommended value is 1Kohm in ATA/ATPI-5 specification. I am looking into why the 4.7-kohm resistor was chosen for the EVM and I will follow-up.

Regards,

Nicholaus

0 Nicholaus_Malone over 2 years ago in reply to Nicholaus_Malone

TI__Mastermind 27925 points

Hello,

Please use the 1K resistor value.

Regards,

Nicholaus

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TUSB6250: Pullup Resistor on IORDY Pin