TCA9802 Datasheet, PDF (16/36 Pages) Texas Instruments – Level-Translating I2C Bus Buffer/Repeater

TCA9802
SCPS266 – MARCH 2017
10 Application and Implementation
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NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
10.1 Application Information
10.1.1 Device Selection Guide
The TCA980x family has 4 different variants, with different strengths of the internal current source as shown in
Table 5.
Part Number
TCA9800
TCA9801
TCA9802
TCA9803
Table 5. TCA980x Family
I_CS: Current Source Value
0.5 mA
1 mA
2 mA
3 mA
It is acceptable to select the TCA9803 as the default, since it is able to drive 400-pF bus capacitance loads at
400 kHz. For system designers looking to optimize selection, see the Detailed Design Procedure section for
single device for detailed examples of how to select a part number for a specific application.
10.1.2 Special Considerations for the B-side
The TCA980x supports many types of connections between other TCA980x and other buffers/translators. Care
must be taken to ensure that all of the B-side requirements be satisfied. For example, FET/pass-gate based
translators typically cannot be used on the B-side, because they require pull-up resistors on both sides, and
when one side is pulling low, the FET/switch closes, likely causing I_EXT-I to be violated (See the I_EXT-I section for
more information).
The FET or Pass-Gate Translators and Buffered Translators/Level-shifters sections list some use-cases that are
not supported or require special considerations when connected to the B-ports, note that these considerations
only apply to the B-side of the TCA980x family.
10.1.2.1 FET or Pass-Gate Translators
Some translators are based on pass-gates for translation support. In most of the use cases, external pull-up
resistors are required to pull the bus to the voltage rail.
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