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Pullup and pulldwon resistors in DS90C387A schematic

Other Parts Discussed in Thread: DS90C387

I found the pull-up and pull-down resistors at such as R_FB,BAL pins are 10ohm in the AN<LDI demonsrtation Kit user muanula (LDI3V8BT-112)>. Please confirm whether is10ohm resistors ok? In general, the pull-up and pull-down resistor are larger.

  • You are correct, the input resistor used is very small. The input current to the device is very small, so I would also use a bigger resistor, with the typical 4.7K value.

  • Hi Ted,

    The schematic referenced in the user manual is for the DS90C387/388 evaluation board. The R_FB and BAL pins on the EVM are intended to be configured through the headers/jumpers. The 10ohm series resistor for each pin was a pad option to allow users to populate different values as needed. A higher pullup/pulldown value can be used to set the logic High/Low state of the pins.

    Dac Tran

    SVA / APPS