LAN9730 Datasheet, PDF (49/61 Pages) SMSC Corporation – High-Speed Inter-Chip (HSIC) USB 2.0

High-Speed Inter-Chip (HSIC) USB 2.0 to 10/100 Ethernet Controller
Datasheet
6.5.2
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 Table 6.14.
 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.
 Do not drive input signals without power supplied to the device.
 It is acceptable for the 3.3 V supplies to remain powered up while the 1.2 V supplies are at zero
volts for a period not to exceed 750 ms. In this case, nRESET must be asserted while 1.2 V is off,
and must remain asserted for a minimum of 50 ms after the 1.2 V supplies reach operational level.
Configuration straps must meet the requirements specified in Section 6.5.4, "Reset and
Configuration Strap Timing," on page 51.
Note: When operating with an external 1.2 V power source, the 1.2 V input must not exceed the 3.3 V
source by more than 0.4 V.
Note: Violation of these specifications may damage the device.
Note: A Power-On Reset (POR) occurs whenever power is initially applied to the device, or if power
is removed and reapplied to the device. A timer within the device will assert the internal reset
for approximately 22 ms.
t_pon
All 3.3 V Power
Supply Pins
All 1.2 V Power
Supply Pins
Figure 6.2 Power Sequence Timing
SYMBOL
t_pon
Table 6.14 Power Sequence Timing Values
DESCRIPTION
MIN
Power supply turn on time
0
TYP
MAX UNITS
750
ms
SMSC LAN9730/LAN9730i
49
DATASHEET
Revision 1.1 (05-13-13)