LAN8820 datasheet(66/83 Pages) MICROCHIP

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LAN8820/LAN8820I

DS00001871B-page 66

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5.5.2

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 5-11.

• 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 opera-

tional limits), a power-on reset must be executed once all power supplies reach operational levels. Refer to Sec-

tion 5.5.3, "Power-On Hardware Reset Timing," on page 67 for power-on reset requirements.

• Do not drive input signals without power supplied to the device.

Note:

Violation of these specifications may damage the device.

FIGURE 5-2:

POWER SEQUENCE TIMING

TABLE 5-11:

POWER SEQUENCE TIMING VALUES

Symbol

Description

Min

Typ

Max

Units

tpon

Power supply turn on time

All 3.3V Power

Supply Pins

All 1.2V Power

Supply Pins

tpon

LAN8820 Datasheet(PDF) 66 Page - Microchip Technology