LAN89730 datasheet(200/218 Pages) MICROCHIP

200 / 218 page

LAN89730

DS60001348A-page 200

 2013-2015 Microchip Technology Inc.

7.6.2

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 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.

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

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.

Note:

While the internal power-on reset circuit may assert during brown-out conditions, this is not guaranteed.

For proper operation in applications where brown-outs may occur, use of an external reset circuit is recom-

mended.

FIGURE 7-2:

POWER SEQUENCE TIMING

TABLE 7-15:

POWER SEQUENCE TIMING VALUES

Symbol

Description

Min.

Typ.

Max.

Unit

tpon

Power supply turn on time

All 3.3 V Power

Supply Pins

All 1.2 V Power

Supply Pins

tpon

LAN89730 Datasheet(PDF) 200 Page - Microchip Technology