The MC12148 requires an external parallel tank circuit consisting of the inductor (L) and capacitor (C). A varactor diode may be incorporated into the tank circuit to provide a voltage variable input for the oscillator (VCO). This device may also be used in many other applications requiring a fixed frequency clock.

The ECL output circuitry of the MC12148 is not a traditional open emitter output structure and instead has an on–chip termination resistor with a nominal value of 500 ohms. This facilitates direct ac–coupling of the output signal into a transmission line. Because of this output configuration, an external pull–down resistor is not required to provide the output with a dc current path. This output is intended to drive one ECL load. If the user

needs to fanout the signal, an ECL buffer such as the MC10EL16 Line Receiver/Driver should be used. NOTE: The MC12148 is NOT useable as a crystal oscillator.

• Typical Operating Frequency Up to 1100 MHz

• Low–Power 20 mA at 5.0 Vdc Power Supply

• 8–Pin SOIC Package

• Phase Noise –90 dBc/Hz at 25 kHz Typical