Datasheet

Hi-Speed USB 2.0 to 10/100/1000 Ethernet Controller
Datasheet
Revision 1.0 (11-01-10) 48 SMSC LAN7500/LAN7500i
DATASHEET
7.5.2 Power Sequence Timing
Power supplies must adhere to the following rules:
 All power supplies of the same voltage must be powered up/down together.
 There is no power-up sequencing requirement, however all power supplies must reach operational
levels within the time periods specified in Tabl e 7. 15 .
 There is no power-down sequencing or timing requirement, however the device must not be
powered for an extended period of time without all supplies at operational levels.
 Following initial power-on, or if a power supply brownout occurs (i.e., one or more supplies drops
below operational limits), a power-on reset must be executed once all power supplies reach
operational levels. Refer to Section 7.5.3, "Power-On Reset Timing," on page 49 for power-on reset
requirements.
 With the exception of VBUS_DET, do not drive input signals without power supplied to the device.
Note: Violation of these specifications may damage the device.
Note: The VDDVARIO power supply can be run at 2.5V or 3.3V.
Note: The magnetics power supply can be run at 2.5V or 3.3V.
Figure 7.2 Power Sequence Timing
Table 7.15 Power Sequence Timing Values
SYMBOL DESCRIPTION MIN TYP MAX UNITS
t
pon
Power supply turn on time 0 25 mS
All 3.3V Power
Supply Pins
All 2.5V Power
Supply Pins
All 1.2V Power
Supply Pins
t
pon