LTC6948-3 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC6948-3
Linear Technology
'LTC6948-3' PDF : 36 Pages View PDF
LTC6948
Typical Applications
Driving a Modulator LO for High Image Rejection and Low Noise Floor
1.8nF
0.1µF 3.3V
1µF
66.5Ω 10µH
5V
15Ω
2.2nF
1µF
68nF
66.5Ω
0.01µF
0.01µF
1µF
61.44MHz
51.1Ω
SPI BUS
0.1µF
3.3V
3.3V
REF+
STAT
CS
SCLK
SDI
SDO
LDO
VD+
LTC6948-3
BVCO
GND
CMA
CMB
CMC
GND
TB
TUNE
1µF
2.2µF
R = 1, fPFD = 61.44MHz
N = 73.24 TO 84.64
LBW = 180kHz
O=2
0.1µF
3.3V 68nH
0.1µF
68nH 100pF
UNUSED OUTPUT
AVAILABLE FOR
OTHER USE
50Ω
3.3V
1µF
0.01µF
10nH
100pF
AVAGO
VMMK-2503
100pF
LPF
5V
3.3V
0.1µF
1Ω
4.7µF
1nF
MINI-CIRCUITS
LFCN-2600+
BASEBAND
I-CHANNEL
fLO = 1500MHz TO 2600MHz IN 117.2Hz STEPS
PLO = 13.5dBm, ~ <–40dBc ODD HARMONIC CONTENT
~ <–30dBc EVEN HARMONIC CONTENT
50Ω 1nF
1nF
100nF
EN
GND
LOP
VCC2
LOM
GNDRF
GND
NC
LINOPT
LTC5588-1
RF
NC
GNDRF
NC
3.3V
1.3Ω
4.7µF
1nF
6.8pF RF OUTPUT, 1500MHz TO 2600MHz CARRIER
0.2pF
34
Measured Image Rejection and LO
Leakage Ratio vs Output Frequency
–20
BASEBAND = 100kHz AT 500mVPK
–30
LO LEAKAGE RATIO
–40
–50
–60
–70
UNADJUSTED
IMAGE REJECTION
–80
1500 1700 1900 2100
2300
OUTPUT FREQUENCY (MHz)
2500
6948 TA02b
BASEBAND
Q-CHANNEL
Measured Noise Floor at 70MHz
Offset vs RF Output Power
–148
fLO = 2100MHz
BASEBAND = 2kHz SINE
–150
–152
–154
–156
–158
–160
–162
–20
–15 –10 –5
0
5
OUTPUT POWER (dBm)
6948 TA02c
For more information www.linear.com/LTC6948
6948 TA02a
6948f
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