TXB0104ZXUR datasheet(21/43 Pages) TI

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9.2.2 Detailed Design Procedure

To begin the design process, determine the following:

• Input voltage range

- Use the supply voltage of the device that is driving the TXB0104 device to determine the input voltage range.

For a valid logic high, the value must exceed the VIH of the input port. For a valid logic low, the value must be

less than the VIL of the input port.

• Output voltage range

- Use the supply voltage of the device that the device is driving to determine the output voltage range.

- External pullup or pulldown resistors are not recommended. If mandatory, it is recommended that the value

must be larger than 50 kΩ.

• An external pulldown or pullup resistor decreases the output VOH and VOL. Use the below equations to draft

estimate the VOH and VOL as a result of an external pulldown and pullup resistor.

VOH = VCCx × RPD / (RPD + 4.5 kΩ)

VOL = VCCx × 4.5 kΩ / (RPU + 4.5 kΩ)

Where

• VCCx is the output port supply voltage on either VCCA or VCCB

• RPD is the value of the external pull down resistor

• RPU is the value of the external pull up resistor

• 4.5 kΩ is the counting the variation of the serial resistor 4 kΩ in the I/O line.

9.2.3 Application Curves

Figure 9-1. Level-Translation of a 2.5-MHz Signal

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TXB0104

SCES650J – APRIL 2006 – REVISED OCTOBER 2020

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TXB0104ZXUR 数据表(PDF) 21 Page - Texas Instruments