Datasheet

LTC6945
26
6945f
LTC6945 Wideband Frequency Hopping Local Oscillator
TYPICAL APPLICATIONS
Frequency Hopping
LO
OUT
Frequency,
LO1 = 450MHz, LO2 = 700MHz
TIME (μs)
–0.6
LO
OUT
FREQUENCY (MHz)
MUTE
VOLTAGES (V)
3
450
0
0.4
6945 TA02b
2
1
0
–0.4 –0.2 0.2
550
650
750
0.6
MUTE1 MUTE2
Frequency Hopping
LO
OUT
Power,
LO1 = 450MHz, LO2 = 700MHz
Frequency Hopping
LO
OUT
Spectrum,
LO1 = 450MHz Muted,
LO2 = 700MHz
FREQUENCY (MHz)
400
POWER (dBm)
–80
–20
–10
0
500
600
650
6945 TA02d
–100
–40
–60
–90
–30
–110
–50
–70
450
550
700
750
f
PFD
= 1MHz
OD = 2
–95dBc
V
VCO
+
GND
GND
GND
GND
GND
VCO
+
VCO
–
V
REFO
+
REFO
STAT
CS
SCLK
SDI
SDO
V
D
+
MUTE GND RF
–
GND
LTC6945
O_DIV = 2
RF
+
V
RF
+
BB
REF
–
3.3V
0.1μF
100MHz
REF
REF
+
V
REF
+
CP V
CP
+
GND
+
0.01μF
100pF
700MHz TO 1400MHz
1.0μF
22nF
LT1678IS8
274Ω
4.99k
4.99k
267nF
470pF
0.1μF
0.1μF
47μF
470pF
3.3V
3.3V
SPI BUS
MUTE1
0.1μF
0.01μF
180nH180nH
3.3V
3.3V
3.3V
0V
3.3V
MUTE1
MUTE2
0V
3.3V
270pF
50Ω
270pF
13.3nF
12V
RFMD
UMS-1400-A16-G
100pF
5V
0.1μF
0.1μF
LOOP BANDWIDTH = ~7.6kHz
14V
5V
3.3V
100Ω
V
TUNE
+
–
V
VCO
+
GND
GND
GND
GND
GND
VCO
+
VCO
–
V
REFO
+
REFO
STAT
CS
SCLK
SDI
SDO
V
D
+
MUTE GND RF
–
GND
LTC6945
O_DIV = 2
RF
+
V
RF
+
BB
REF
–
3.3V
0.1μF
51.1Ω
REF
+
V
REF
+
CP V
CP
+
GND
+
0.01μF
100pF
700MHz TO 1400MHz
1.0μF
22nF
LT1678IS8
274Ω
4.99k
4.99k
267nF
470pF
0.1μF
0.1μF
47μF
470pF
3.3V
3.3V
SPI BUS
MUTE2
0.1μF
0.01μF
180nH180nH
3.3V
3.3V
POWER
COMBINER
3.3V
100ns
270pF
50Ω
270pF
1
2
S LO OUT
6945 TA02a
LO2 = 350MHz TO 700MHz
LO1 = 350MHz TO 700MHz
13.3nF
12V
RFMD
UMS-1400-A16-G
100pF
5V
0.1μF
0.1μF
LOOP BANDWIDTH = ~7.6kHz
14V
5V
3.3V
100Ω
V
TUNE
+
–
TIME (μs)
–0.6
LO
OUT
POWER (MHz)MUTE VOLTAGES (V)
3
–5.0
0
0.4
6945 TA02c
2
1
0
–0.4 –0.2 0.2
–4.5
–4.0
–3.5
0.6
MUTE1 MUTE2