10.2 Ethernet Clock

One 25-MHz clock source is required by the SAM9X60D1G-I/LZB Ethernet port. The clock is generated by a Microchip ultra-low-power MEMS oscillator.

The DSC6102HI2B-025.0000 device delivers a controllable 25-MHz clock to the KSZ8081 Ethernet PHY with an ultra-low power consumption of about 3 mA in Active mode.

For more information about the MEMS DSC61xxB, see Reference Documents.

Figure 10-2. 25-MHz MEMS Oscillator Schematic

The 25-MHz clock can be enabled/disabled as required by the application through the 25M_EN signal available on pin 75. Three configurations are possible:

25M_EN pin connected to VDD (VDD_3V3). The clock is enabled.
25M_EN connected to GND. The clock is stopped.
25M_EN connected to a GPIO. The clock is controlled dynamically.