Datasheet

LTC6946
30
6946fa
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone]
●
FAX: [phone]
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2011
LT 1111 REV A • PRINTED IN USA
RELATED PARTS
TYPICAL APPLICATION
PART NUMBER DESCRIPTION COMMENTS
LTC5540/LTC5541
LTC5542/LTC5543
High Dynamic Range Down Mixers 8dB Conversion Gain, 26.4dBm IIP3, 9.6dB NF, 600MHz to 4GHz
LTC5590/LTC5591
LTC5592/LTC5593
High Linearity Dual Mixers 600MHz to 4.5GHz, 8.5dB Gain, 26.2dBm IIP3, 9.9dB NF
LTC5569 Broadband Dual Mixer 300MHz to 4GHz, 26.8dB IIP3, 2dB Gain, 11.7dB NF, 600mW Power
LTC5588-1 Ultrahigh OIP3 I/Q Modulator 200MHz to 6GHz, 31dBm OIP3, –160.6dBm/Hz Noise Floor
LT
®
5575 Direct Conversion I/Q Demodulator 800MHz to 2.7GHz, 22.6dBm IIP3, 60dBm IIP3, 12.7dB NF
LTC6946-2 Driving a Passive Downconverting Mixer
MUTE GND RF
–
RF
+
V
RF
+
BB
REF
+
REF
–
V
REF
+
CP
V
CP
+
GND
V
REFO
+
REFO
STAT
CS
SCLK
SDI
SDO
V
D
+
V
VCO
+
GND
CM
A
CM
B
CM
C
GND
TB
TUNE
LTC6946-2
SPI BUS
3.3V
470pF
51.1Ω
+
15Ω
5V
R
Z
1μF
3.3V
LOOP COMPENSATION
COMPONENT VALUES ARE
APPLICATION SPECIFIC
DEPENDING ON THE LO
FREQUENCY RANGE AND
STEP SIZE AND THE PHASE
NOISE OF THE REFERENCE
C
I
0.01μF
0.1μF
3.3V
3.3V
1μF
0.01μF
0.01μF
2.2μF
C
P
0.01μF
BALUN TDK HHM1525
3.3V
LO2 LO1
LOBIAS
LOSEL
V
CC3
IFBIAS
IFGND
SHDN
GNDGND GND
LTC5541
GND GND
V
CC2
CT
RF
V
CC1
1μF
3.3V
30nH
IF
+
150nH
IF
–
470pF
10MHz
REFERENCE
TOKO
4DFB-1842N-10
22pF
22pF
1μF
3.3V
3.3V
LO = 1842MHz
0.1μF
ADC
150nH
1nF
140MHz
SAW
140MHz
BPF
1.5pF
2.2pF
LNA
IMAGE
BPF
RF IN
1952MHz
TO 2012MHZ
3.3V
22pF
1nF
6946 TA03
RF BLOCKER POWER (dBm)
–20
9
SSB NOISE FIGURE (dB)
10
12
13
14
–10
0
5
18
6946 TA03b
11
–15 –5
15
16
17
RF = 1982MHz
BLOCKER = 2082MHz
LO = LTC6946-2
LO = CLEAN LAB SOURCE
LTC5541 Noise Figure vs Blocker
Power and LO Signal Source
LTC6946-2 Mixer Application
Phase Noise
OFFSET FREQUENCY (Hz)
–130
–140
PHASE NOISE (dBc/Hz)
–110
–90
–150
–120
–100
100 10k 100k 1M 10M
6946 TA03c
–160
1k
RMS NOISE = 0.270°
f
RF
= 1842MHz
f
PFD
= 2MHz
OD = 2
f
STEP
= 1MHz