USB5744

DS00001855K-page 36

10.6

AC Specifications

This section details the various AC timing specifications of the device.

10.6.1

POWER SUPPLY AND RESET_N SEQUENCE TIMING

Figure 10-2 illustrates the recommended power supply sequencing and timing for the device. VDD33 should rise after

or at the same rate as VDD12. Similarly, RESET_N and/or VBUS_DET should rise after or at the same rate as VDD33.

VBUS_DET and RESET_N do not have any other timing dependencies.

10.6.2

POWER-ON AND CONFIGURATION STRAP TIMING

Figure 10-3 illustrates the configuration strap valid timing requirements in relation to power-on, for applications where

RESET_N is not used at power-on. In order for valid configuration strap values to be read at power-on, the following

10.2, "Operating Conditions**," on page 32.

Device configuration straps are also latched as a result of RESET_N assertion. Refer to Section 10.6.3, "Reset and Con-

figuration Strap Timing" for additional details.

FIGURE 10-2:

POWER SUPPLY AND RESET_N SEQUENCE TIMING

TABLE 10-5:

POWER SUPPLY AND RESET_N SEQUENCE TIMING

Symbol

Description

Min

Typ

Max

Units

VDD12 to VDD33 rise time

0

ms

VDD33 to RESET_N/VBUS_DET rise time

0

ms

FIGURE 10-3:

POWER-ON CONFIGURATION STRAP VALID TIMING

TABLE 10-6:

POWER-ON CONFIGURATION STRAP LATCHING TIMING

Symbol

Description

Min

Typ

Max

Units

Configuration strap hold after external power supplies at opera-

tional levels

1ms

VDD12

VDD33

RESET_N/

VBUS_DET

All External

Power Supplies

Configuration

Straps