Texas Instruments TCA39306, Руководство пользователя, Страница: 2 / 15

1 Introduction
The TCA39306 EVM allows the user's to test the device under different loading conditions using selectable
pull-up resistors and loading capacitance. The EVM comes with U1 (DCU package) populated, but supports the
use of the DDF and DTM package. Performance should be similar to DCU package, but the user may want to
test different packages over temperature due to different temperature coefficents.
2 Concept
2.1 EVM Features
• Adjustable pull-up resistors
• Adjustable load capacitance
• Footprint available for DDF and DTM packages
2.2 Adjustable pull-up resistors
TCA39306EVM comes with adjustable pull-up resistors which allows for the user to select from a 4.7 k and 820
Ω resistor. The board itself has a 10 k pull-up resistor on the I2C bus when no resistors are selected from the
adjustable pull up bank. When 4.7 k is selected, the effective pull up resistance is 3.2 kΩ. When only the 820
Ω pull-up is selected, the effective pull up resistance is about 750 Ω. When both adjustable pull-up resistors are
selected the effective resistance is about 650 Ω. The pull-up resistor selectors are shown in
Figure 2-1 .
Table 2-1. Effective pull-up resistor values table
Pull-up resistor (Ω) Equivalent pull-up resistance (Ω)
10k || 4.7 k 3.2 k
10k || 820 ~750
10k || 4.7 k || 820 ~650
Figure 2-1. Adjustable pull-up resistors
Introduction www.ti.com
2 TCA39306 EVM User's Guide SCPU045 – JUNE 2021
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