DS90UB925Q-Q1: IDx resistor divider

Scott Taylor21

Part Number: DS90UB925Q-Q1

Page 5 of the datasheet says this for the IDx pin, "External pull-up to VDD33 is required under all conditions" and refers to figure 19. Figure 19 on page 26 shows R1 as a pull-up and R2 as a pull-down. Table 5 just below figure 19 for address 1 shows R1 as open, i.e., no pull-up. Which of these is correct?

over 6 years ago

0 Steven(Shenzhen) Shi over 6 years ago

TI__Mastermind 30515 points

Hi, Taylor,
I think here it has little missed message.
1. IDX address is set by external pullup and pulldown resistor, differentiated by this divided voltage.
2. if you need pullup resistor option, the pullup voltage must be VDD33's voltage.

I2C Serial Control Bus Device ID Address Select
External pull-up to VDD33 is required under all conditions, DO NOT FLOAT.
Connect to external pull-up and pull-down resistor to create a voltage divider. See Figure 19.

best regards,
Steven

0 Scott Taylor21 over 6 years ago in reply to Steven(Shenzhen) Shi

Prodigy 230 points

There are two statements, one that there MUST be a pullup. The other that says leave the pullup off for address 0. They can't both be correct.

0 Casey McCrea over 6 years ago in reply to Scott Taylor21

TI__Guru** 103215 points

Scott,

The page 5 statement should be clarified to say "External pull up or pull down is required under all conditions". The point is that the pin should not be floated.

Best Regards,
Casey

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DS90UB925Q-Q1: IDx resistor divider