1 0 MHz t o 1 0 5 0 MHz In t e g ra t e d
RF Os c illa t o r w it h Bu ffe re d Ou t p u t s
_____________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(Per Typical Operating Circuit, V
= +3.0V, V
= 1.5V, SHDN = V
load at OUT = 50Ω, load at OUT = 50Ω, L1 = coaxial
CC
TUNE
CC,
ceramic resonator: Trans-Tech SR8800LPQ1357BY, C6 = 1pF, T = +25°C, unless otherwise noted.)
A
OUTPUT SPECTRUM
FUNDAMENTAL NORMALIZED TO 0dB
PHASE NOISE vs. TEMPERATURE
SINGLE SIDEBAND PHASE NOISE
-104
-106
-108
-110
-112
-114
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-40
-50
SSB @ ∆f = 25kHz
L1 = 5nH INDUCTOR
C6 = 1.5pF
MAX620
-60
-70
-80
L1 = 5nH INDUCTOR
C6 = 1.5pF
-90
-100
-110
-120
-130
-140
-150
L1 = COAXIAL
CERAMIC RESONATOR
(TRANS-TECH
SR8800LPQ1357BY)
C6 = 1pF
L1 = COAXIAL CERAMIC RESONATOR
(TRANS-TECH SR8800LPQ1357BY)
C6 = 1pF
0
1.3
2.6
3.9
5.2
6.5
-40
-20
0
20
40
60
80
0.1
1
10
100
1000
FREQUENCY (GHz)
TEMPERATURE (°C)
OFFSET FREQUENCY (kHz)
_______________________________________________________________P in De s c rip t io n
PIN
NAME
FUNCTION
Oscillator DC Supply Voltage. Decouple VCC1 with 1000pF capacitor to ground. Use a capacitor with low
series inductance (size 0805 or smaller). Further power-supply decoupling can be achieved by adding a
10Ω resistor in series from VCC1 to the supply. Proper power-supply decoupling is critical to the low noise
and spurious performance of any oscillator.
1
VCC1
2
3
TANK
FDBK
Oscillator Tank Circuit Connection. Refer to the Applications Information section.
Oscillator Feedback Circuit Connection. Connecting capacitors of the appropriate value between FDBK and
TANK and between FDBK and GND tunes the oscillator’s reflection gain (negative resistance) to peak at the
desired oscillation frequency. Refer to the Applications Information section.
Logic-Controlled Input. A low level turns off the entire circuitry such that the IC will draw only leakage current
at its supply pins. This is a high-impedance input.
4
5
SHDN
OUT
Open-Collector Output Buffer (complement). Requires external pull-up to the voltage supply. Pull-up can be
resistor, choke, or inductor (which is part of a matching network). The matching-circuit approach provides
the highest-power output and greatest efficiency. Refer to Table 1 and the Applications Information section.
OUT may be used with OUT in a differential output configuration.
6
7
GND
Ground Connection. Provide a low-inductance connection to the circuit ground plane.
Output Buffer DC Supply Voltage. Decouple VCC2 with a 1000pF capacitor to ground. Use a capacitor with
low series inductance (size 0805 or smaller).
VCC2
Open-Collector Output Buffer. Requires external pull-up to the voltage supply. Pull-up can be resistor,
choke, or inductor (which is part of a matching network). The matching-circuit approach provides the high-
est-power output and greatest efficiency. Refer to Table 1 and the Applications Information section. OUT
may be used with OUT in a differential output configuration.
8
OUT
6
_______________________________________________________________________________________