NOTE: The MC12149 is NOT suitable as a crystal oscillator.
Operates Up to 1.3GHz
Space–Efficient 8–Pin SOIC Package
Low Power 15mA Typical @ 3.0V Operation
Supply Voltage of 2.7 to 5.5V
Typical 900MHz Performance
– Phase Noise –105dBc/Hz @ 100KHz Offset
– Tuning Voltage Sensitivity of 20MHz/V
Output Amplitude Adjustment Capability
Two High Drive Outputs With a Typical Range from –8dBm to –2dBm
One Low–Drive Output for Interfacing to a Prescaler
The device has three high frequency outputs which make it attractive
for transceiver applications which require both a transmit and receive
local oscillator (LO) signal as well as a lower amplitude signal to drive the prescaler input of the frequency synthesizer. The
outputs Q and QB are available for servicing the receiver IF and transmitter up–converter single–ended. In receiver applications,
the outputs can be used together if it is necessary to generate a differential signal for the receiver IF. Because the Q and QB
outputs are open collector, terminations to the V CC supply are required for proper operation. Since the outputs are
complementary, BOTH outputs must be terminated even if only one is needed. The Q and QB outputs have a nominal drive level
of –8dBm to conserve power. If addition signal amplitude is needed, a level adjustment pin (CNTL) is available, which when tied
to ground, boosts the nominal output levels to –2dBm.
A low power VCO output (Q2) is also provided to drive the prescaler input
of the PLL. The amplitude of this signal is nominally 500mV which is suitable for most prescalers.
External components required for the MC12149 are: (1) tank circuit (LC network); (2) Inductor/capacitor to provide the
termination for the open collector outputs; and (3) adequate supply voltage bypassing. The tank circuit consists of a high–Q
inductor and varactor components. The preferred tank configuration allows the user to tune the VCO across the full supply range.
VCO performance such as center frequency, tuning voltage sensitivity, and noise characteristics are dependent on the particular
components and configuration of the VCO tank circuit.