tr - Rise Time (ns)

0

50

100

150

200

250

300

0

100

200

300

400

D001

VCCB = 2.5 V

TCA9800

TCA9801

TCA9802

TCA9803

24

TCA9803

SCPS267B – MARCH 2017 – REVISED FEBRUARY 2020

www.ti.com

Product Folder Links: TCA9803

Submit Documentation Feedback

Copyright © 2017–2020, Texas Instruments Incorporated

Table 7. Design Requirements (continued)

Parameter

Description

Acceptable Range

Example Value/Target

VCCA

VCCA supply voltage

0.8 V-3.6 V

2.5 V

VCCB

VCCB supply voltage

1.65 V-3.6 V

2.5 V

fSCL

I2C clock frequency

400 kHz

10.2.2.2 Detailed Design Procedure

Selecting the pull-up resistor required for the A-side is well documented already, see the I2C Bus Pullup Resistor

Calculation application report. The rest of this section deals only with selection of a device based on the B-side

design requirements.

Selection process of each device is identical to the procedure described in the Device Selection Guide section,

except that it must be done for each individual TCA980x. This section jumps straight to the selection graphs to

show the selection process. See the Detailed Design Procedure section for single device for detailed information.

As shown in Figure 30, the shaded region is the appropriate region based on design requirements listed in

Table 7. Any line that touches this shaded region is able to meet the design requirements. In this example, the

TCA9803, TCA9802, and TCA9801 are able to satisfy the design requirements, since they all touch the shaded

region. The TCA9800 falls below the shaded region.

Based on the selection graph shown above, the TCA9801 is selected, since it is the lowest-power device which

touches the shaded region (red trace). The TCA9803 or the TCA9802 may also be used without any

consequences.

10.2.2.3 Application Curve

Figure 30. Selection Guide Based On Example Design Requirements

10.2.3 Parallel Device Use Case

The TCA980x family supports multiple TCA980x used in parallel. The A-sides of the TCA980x are allowed to be

connected together.

It is critical to note that there are no external sources of current allowed on the B-side ports, since this can affect

device operation shown in the IEXT-I section.

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 section 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.