8.3 Initialization Set Up

The general power-up sequence for the TUSB320 device (EN_N tied to ground) is as follows:

1. System is powered off (device has no VDD). The TUSB320 device is configured internally in UFP mode with

Rds on CC pins (dead battery).

2. VDD ramps – POR circuit. VDD must ramp within 25 ms or less. IO pull-up power rail (for example, pull up on

ID, INT, SCL, SDA, ADDR, and PORT) must ramp with VDD or lag after VDD.

3. I2C supply ramps up.

4. The TUSB320 device enters unattached mode and determines the voltage level from the PORT pin. This

determines the mode in which the TUSB320 device operates (DFP, UFP, and DRP).

5. The TUSB320 device monitors the CC pins as a DFP and VBUS for attach as an UFP.

6. The TUSB320 device enters active mode when attach has been successfully detected.

9 Power Supply Recommendations

The TUSB320 device has a wide power supply range from 2.7 to 5 V, and can be powered by a battery system.

10 Layout

10.1 Layout Guidelines

1. An extra trace (or stub) is created when connecting between more than two points. A trace connecting pin

A6 to pin B6 will create a stub because the trace also has to go to the USB Host. Ensure that:

• A stub created by short on pin A6 (DP) and pin B6 (DP) at Type-C receptacle does not exceed 3.5 mm.

• A stub created by short on pin A7 (DM) and pin B7 (DM) at Type-C receptacle does not exceed 3.5 mm.

2. A 100-nF capacitor should be placed as close as possible to the TUSB320 VDD pin.

10.2 Layout Example

Figure 10-1. TUSB320 Layout

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TUSB320, TUSB320I

SLLSEN9F – MAY 2015 – REVISED MARCH 2022

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Product Folder Links: TUSB320 TUSB320I