LAN8740A Datasheet, PDF (126/136 Pages) Microchip Technology – Small Footprint MII/RMII 10/100 Energy Efficient Ethernet Transceiver with HP Auto-MDIX and flexPWR® Technology

LAN8740A/LAN8740Ai
Note 1: The maximum allowable values for frequency tolerance and frequency stability are application dependent.
Since any particular application must meet the IEEE ±50 ppm Total PPM Budget, the combination of these
two values must be approximately ±45 ppm (allowing for aging).
2: Frequency Deviation Over Time is also referred to as Aging.
3: The total deviation for the Transmitter Clock Frequency is specified by IEEE 802.3u as
±50 ppm.
4: The crystal must support 100 µW operation to utilize this circuit.
5: 0°C for commercial version, -40°C for industrial version
6: +70°C for commercial version, +85°C for industrial version
7: 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 (C₁ and C₂ in Figure 5-9). The external load capacitors, C₁ and
C₂, determine the accuracy of the 25.000 MHz frequency.
DS00001987A-page 126
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