dp83840a National Semiconductor Corporation, dp83840a Datasheet - Page 25

• Manufacturer Part Number: dp83840a
• Description: 10/100 Mb/s Ethernet Physical Layer
• Manufacturer: National Semiconductor Corporation

Version A
3.0 Functional Description
* NOTE:
20 MHz
50 MHz
50ppm
50ppm
* 33 pF
* 33 pF
OSC
OSC
REFER TO CRYSTAL MANUFACTURE FOR RECOMMENDED CRYSTAL LOAD CAPACITANCE
50 MHz
50ppm
OSC
20 MHZ
0.005%
FIGURE 8. 50 MHz Reference and 20 MHz Crystal
(Continued)
FIGURE 7. 50 MHz and 20 MHz References
CLK25M
TX_CLK
OSCIN
REFIN
X2
X1
CLK25M
TX_CLK
OSCIN
REFIN
X2
X1
25
SELECT
SPEED
MUX
SELECT
SPEED
MUX
DIV 2.0
DIV 2.0
20 MHz TO 10 Mb/s SECTION
25 MHz TO 100 Mb/s SECTION
25 MHz FROM 100 Mb/s SECTION
2.5 MHz (OR 10 MHz) FROM 10 Mb/s SECTION
National Semiconductor
20 MHz TO 10 Mb/s SECTION
25 MHz TO 100 Mb/s SECTION
25 MHz FROM 100 Mb/s SECTION
2.5 MHz (OR 10 MHz) FROM 10 Mb/s SECTION