LAN8710A Datasheet, PDF(77/82 Page) SMSC Corporation – Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR Technology

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LAN8710A Datasheet, PDF (77/82 Pages) SMSC Corporation – Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR Technology

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5.6

Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWRÂ® Technology

Datasheet

Clock Circuit

The device can accept either a 25MHz crystal or a 25MHz single-ended clock oscillator (Â±50ppm)

input. If the single-ended clock oscillator method is implemented, XTAL2 should be left unconnected

and XTAL1/CLKIN should be driven with a nominal 0-3.3V clock signal. See Table 5.13 for the

recommended crystal specifications.

PARAMETER

Crystal Cut

Crystal Oscillation Mode

Crystal Calibration Mode

Frequency

Frequency Tolerance @ 25oC

Frequency Stability Over Temp

Frequency Deviation Over Time

Total Allowable PPM Budget

Shunt Capacitance

Load Capacitance

Drive Level

Equivalent Series Resistance

Operating Temperature Range

XTAL1/CLKIN Pin Capacitance

XTAL2 Pin Capacitance

Table 5.13 Crystal Specifications

SYMBOL

Ffund

Ftol

Ftemp

Fage

MIN

NOM

MAX

AT, typ

Fundamental Mode

Parallel Resonant Mode

25.000

Â±50

+/-3 to 5

Â±50

7 typ

20 typ

300

Note 5.23

+85

3 typ

UNITS NOTES

MHz

PPM

Ohm

Note 5.20

Note 5.21

Note 5.22

Note 5.24

Note 5.20

The maximum allowable values for Frequency Tolerance and Frequency Stability are

application dependant. Since any particular application must meet the IEEE Â±50 PPM Total

PPM Budget, the combination of these two values must be approximately Â±45 PPM

(allowing for aging).

Note 5.21 Frequency Deviation Over Time is also referred to as Aging.

Note 5.22 The total deviation for the Transmitter Clock Frequency is specified by IEEE 802.3u as

Â±100 PPM.

Note 5.23 0oC for extended commercial version, -40oC for industrial version.

Note 5.24

This number includes the pad, the bond wire and the lead frame. PCB capacitance is not

included in this value. The XTAL1/CLKIN pin, XTAL2 pin and PCB capacitance values are

required to accurately calculate the value of the two external load capacitors. The total load

capacitance must be equivalent to what the crystal expects to see in the circuit so that the

crystal oscillator will operate at 25.000 MHz.

SMSC LAN8710A/LAN8710Ai

DATASHEET

Revision 1.4 (08-23-12)

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