lt5560 Linear Technology Corporation, lt5560 Datasheet - Page 22

• Manufacturer Part Number: lt5560
• Description: 0.01mhz To 4ghz Low Power Active Mixer
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
LT5560
Application Examples
The LT5560 may be used as an upconverting or
downconverting mixer in a wide variety of applications,
in addition to those identifi ed in the datasheet. The fol-
lowing examples illustrate the versatility of the LT5560.
(The component values for each case can be found in
Tables 3, 5 and 7).
Figure 16 demonstrates gain, IIP3 and IIP2 performance
versus RF Output Frequency for the LT5560 when used
as a 240MHz upconverting mixer. The input frequency
is 10MHz, with an LO frequency of 250MHz. The circuit
uses the topology shown in Figure 1.
The performance in a 140MHz downconverting mixer
application is plotted in Figure 17. In this case the gain,
IIP3 and NF are shown as a function of LO power with an
IF output frequency of 10MHz. The circuit topology for
this case is shown in Figure 3.
22
Figure 16. LT5560 Performance in 240MHz
Upconverting Mixer Application
14
12
10
8
6
4
0
2
170
f
f
IF
LO
= 10MHz
190
= f
RF
OUTPUT FREQUENCY (MHz)
+ f
210
U
IF
230
GAIN
U
250
IIP3
IIP2
270
W
290
5560 F16
310
58
56
54
52
50
48
46
44
U
The LT5560 operation at higher frequencies is demon-
strated in Figure 18, where the performance of a 3600MHz
downconverting mixer is shown. The conversion gain, IIP3
and DSB NF are plotted for an RF input frequency range
of 3300 to 3800MHz and an IF frequency of 450MHz. The
circuit is the same topology as shown in Figure 2.
11
Figure 17. LT5560 Performance in 140MHz
Downconverting Mixer Application
9
7
5
1
3
–10
11
10
9
8
7
6
5
4
3
2
1
3300
Figure 18. LT5560 Performance as a
3600MHz Downconverting Mixer
f
f
f
RF
IF
LO
= 10MHz
= 140MHz
= 150MHz
–8
3400
LO INPUT POWER (dBm)
RF INPUT FREQUENCY (MHz)
–6
3500
GAIN
DSB NF
–4
GAIN
IIP3
3600
SSB NF
–2
IIP3
3700
0
5560 F17
2
5560 F18
3800
14
12
10
8
6
4
5560f