4 ac characteristics, Ac characteristics – Intel 82540EP User Manual

Page 27

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Networking Silicon — 82540EP

Datasheet

21

4.4

AC Characteristics

Table 9. AC Characteristics: 3.3 V Interfacing

Symbol

Parameter

Min

Typ

Max

Unit

PCICLK

Clock frequency in PCI mode

66

MHz

Table 10. 25 MHz Clock Input Requirements

Symbol

Parameter

a

Min

Typ

Max

Unit

fi_TX_CLK

TX_CLK_IN frequency

25 - 50 ppm

25

25 + 50

ppm

MHz

a. This parameter applies to an oscillator connected to the Crystal One (XTAL1) input. Alternatively, a crystal may be connected

to XTAL1 and XTAL2 as the frequency source for the internal oscillator.

Table 11. Link Interface Clock Requirements

Symbol

Parameter

Min

Typ

Max

Unit

fGTX

a

GTX_CLK frequency

125

MHz

a. GTX_CLK is used externally for test purposes only.

Table 12. EEPROM Interface Clock Requirements

Symbol

Parameter

Min

Typ

Max

Unit

fSK

1

MHz

Table 13. AC Test Loads for General Output Pins

Symbol

Signal Name

Value

Units

CL

TDO

10

pF

CL

PME#, SDP[7:0]

16

pF

CL

EE_DI, EE_SK

18

pF

CL

RX_ACTIVITY, TX_ACTIVITY, LINK_UP

20

pF

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