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2016-01-0001

PT0579

01/27/16

7

PI4GTL2002

2-bit bidirectional low voltage translator

For unidirectional up translation, lower voltage to higher voltage, the reference transistor is connected the same as for a down

translation. A pull-up resistor is required on the higher voltage side (Dn or Sn) to get the full HIGH level, since the GTL-TVC

device will only pass the reference source (SREF) voltage as a HIGH when doing an up translation. The driver on the lower

voltage side only needs pull-up resistors if it is open-drain.

Figure.5 Unidirectional down translation to protect higher voltage processor pins

Pull-up resistors and minimum values

Sizing the pull-up resistor on an open-drain bus is specific to the individual application and

is dependent on the following driver characteristics:

 The driver sink current

 The V

 The V

 The V

 Frequency of operation

The following tables can be used to estimate the pull-up resistor value in different use cases so that the minimum resistance for

the pull-up resistor can be found.

Tables in bellow contain suggested minimum values of pull-up resistors for the PI4GTL2002 with typical voltage translation

levels and drive currents.

The calculated values assume that both drive currents are the same.

resistor chosen in the final application should be equal to or larger than the values shown in the tablew to ensure that the pass

voltage is less than 10 % of the VCC voltage, and the external driver should be able to sink the total current from both pull-up

resistors.