SEMICONDUCTOR
TECHNICAL DATA
LOW POWER
VOLTAGE CONTROLLED
OSCILLATOR BUFFER
Order this document by MC12149/D
8
1
Q2
VCC
7
2
Q
CNTL
6
3
GND
TANK
5
4
QB
VREF
Device
Operating
Temperature Range
Package
ORDERING INFORMATION
MC12149D
TA = –40 to 85
°
C
SO–8
D SUFFIX
PLASTIC PACKAGE
CASE 751
(SO–8)
8
1
(Top View)
PIN CONNECTIONS
1
MOTOROLA RF/IF DEVICE DATA
The MC12149 is intended for applications requiring high frequency signal
generation up to 1300 MHz. An external tank circuit is used to determine the
desired frequency of operation. The VCO is realized using an
emitter–coupled pair topology. The MC12149 can be used with an integrated
PLL IC such as the MC12202 1.1 GHz Frequency Synthesizer to realize a
complete PLL sub–system. The device is specified to operate over a voltage
supply range of 2.7 to 5.5 V. It has a typical current consumption of 15 mA at
3.0 V which makes it attractive for battery operated handheld systems.
NOTE: The MC12149 is NOT suitable as a crystal oscillator.
Operates Up to 1.3 GHz
Space–Efficient 8–Pin SOIC or SSOP Package
Low Power 15 mA Typical @ 3.0 V Operation
Supply Voltage of 2.7 to 5.5 V
Typical 900 MHz Performance
– Phase Noise –105 dBc/Hz @ 100 kHz Offset
– Tuning Voltage Sensitivity of 20 MHz/V
Output Amplitude Adjustment Capability
Two High Drive Outputs With a Typical Range from –8.0 to –2.0 dBm
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 VCC 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 –2.0 dBm. A low
power VCO output (Q2) is also provided to drive the prescaler input of the
PLL. The amplitude of this signal is nominally 500 mV 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.
Motorola, Inc. 1998
Rev 4