BUS

MASTER

400 kHz

SDA

SCL

1.65 V

5 k

5 k

EN

SDAA

SCLA

SDAB

SCLB

VCCA VCCB

TCA980x

SDA

SCL

SLAVE

400 kHz

3.3 V

EN

SDAA

SCLA

SDAB

SCLB

VCCA VCCB

TCA980x

1.65 V

BUS A

BUS B

BUS C

Copyright © 2017, Texas Instruments Incorporated

27

TCA9803

www.ti.com

SCPS267B – MARCH 2017 – REVISED FEBRUARY 2020

Product Folder Links: TCA9803

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Copyright © 2017–2020, Texas Instruments Incorporated

NOTE: B-sides of TCA980x devices may never be connected to each other, because the IEXT-I specification limit

is violated. See the IEXT-I for more information.

NOTE: The B-side may not be connected to another translator if it uses a static-voltage offset. The RILC spec is

violated since the static voltage offset adjusts the output resistance to ground to be outside of the RILC spec

requirement, causing the TCA980x to be unable to recognize a low.

Figure 34. Series Use Case

NOTE

Decoupling capacitors are not shown to keep the illustration simple. Decoupling capacitors

(1 µF and 0.1 µF) must be placed close to each power supply pin.

10.2.4.1 Design Requirements

The system designer must first select the correct variant of the TCA980x family for the load. In order to do this,

the information in Table 10 and Table 11 must be known. The setup in Figure 34 is used for these example

design requirements.

Table 10. Design Requirements for Bus B / 1st TCA980x

Parameter

Description

Acceptable Range

Example Value/Target

CL

Load capacitance (bus capacitance) on B-

side

up to 400 pF

300 pF

tr

Rise time

up to 300 ns

≤ 200 ns

VCCA

VCCA supply voltage

0.8 V-3.6 V

1.65 V

VCCB

VCCB supply voltage

1.65 V-3.6 V

3.3 V

fSCL

I2C clock frequency

400 kHz

Table 11. Design Requirements for Bus C / 2nd TCA980x

Parameter

Description

Acceptable Range

Example Value/Target

CL

Load capacitance (bus capacitance) on B-

side

up to 400 pF

100 pF

tr

Rise time

up to 300 ns

≤ 250 ns

VCCA

VCCA supply voltage

0.8 V-3.6 V

3.3 V

VCCB

VCCB supply voltage

1.65 V-3.6 V

1.65 V

fSCL

I2C clock frequency

400 kHz