Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
Datasheet
5.5.2
Power Sequence Timing
This diagram illustrates the device power sequencing requirements. The VDDIO, VDD1A, VDD2A and
magnetics power supplies can turn on in any order provided they all reach operational levels within
the specified time period tpon. Device power supplies can turn off in any order provided they all reach
0 volts within the specified time period poff
.
tpon
tpoff
VDDIO
Magnetics
Power
VDD1A,
VDD2A
Figure 5.2 Power Sequence Timing
Table 5.7 Power Sequence Timing Values
SYMBOL
DESCRIPTION
MIN
TYP
MAX
UNITS
tpon
tpoff
Power supply turn on time
Power supply turn off time
50
mS
mS
500
Note: When the internal regulator is disabled, a power-up sequencing relationship exists between
VDDCR and the 3.3V power supply. For additional information refer to Section 3.7.3,
"REGOFF: Internal +1.2V Regulator Configuration," on page 32.
SMSC LAN8720A/LAN8720Ai
69
Revision 1.4 (08-23-12)
DATASHEET
SMSC [ SMSC CORPORATION ]
