Hello
According to the data sheet of LSF0108, The description of data sheet is unclear for me.
Let me have answer for the below questions regarded to usage Pull Up Resister.
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Question 1 : As the Page 13, what is the explain in Red color. Phrase in red is not related to the Figure 6.
Would you explain about the phrase in red?
10.2.1.2.1 Bidirectional Translation
For the bidirectional clamping configuration (higher voltage to lower voltage or lower voltage to higher voltage),
the EN input must be connected to Vref_B and both pins pulled to HIGH side Vpu through a pullup resistor
(typically 200 kΩ). This allows Vref_B to regulate the EN input. A filter capacitor on Vref_B is recommended. The
master output driver can be push-pull or open-drain (pullup resistors may be required) and the slave device
output can be push-pull or open-drain (pullup resistors are required to pull the Bn outputs to Vpu).
However, if either output is push-pull, data must be unidirectional or the outputs must be tri-state and be
controlled by some direction-control mechanism to prevent HIGH-to-LOW contentions in either direction.
If both outputs are open-drain, no direction control is needed.
In Figure 6, the reference supply voltage (Vref_A) is connected to the processor core power supply voltage.
When Vref_B is connected through a 200 kΩ resistor to a 3.3 V Vpu power supply, and Vref_A is set 1.0 V. The
output of A3 and B4 has a maximum output voltage equal to Vref_A, and the bidirectional interface (Ch1/2,
MDIO) has a maximum output voltage equal to Vpu.
Question2 : in 10.2.3 Multiple Voltage Translation in Single Device - Application Schematic on Data sheet
Page 17
what case for GPIO use Pull Up resister?
When does not GPIO need pull Up resistor?
Detail explanations on Case by Case - Data Direction / Push pull / Open Drain
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Thanks and Best Regards