LT5578_15 Datasheet, PDF (14/16 Pages) Linear Technology – 0.4GHz to 2.7GHz High Linearity Upconverting Mixer

LT5578
TYPICAL APPLICATIONS
The measured room temperature performance is plotted
in Figure 10 for both low side and high side LO drive. At
2600MHz, the gain is approximately –2.8dB with a noise
figure of 11.2dB and OIP3 of about 22.2dBm. Low side
LO yields slightly better overall performance than high
side LO.
700 to 950 MHz Output Matching
The application shown on page 1 has a wider bandwidth
than the 740MHz and 900MHz configurations. Using two
additional components at the RF output allows the band-
12
32
10
SSB NF
8
6
OIP3
4
30
28
LS LO
HS LO
26
24
2
22
0
20
GAIN
–2
18
–4
2200
2300 2400 2500 2600
RF OUTPUT FREQUENCY (MHz)
16
2700
5578 F09
Figure 10. Gain, Noise Figure and OIP3 vs RF Frequency
for the 2600MHz Application
width to be extended to cover the range from 700MHz to
950MHz. Figure 11 compares the broadband return loss
to the typical 740MHz and 900MHz return loss perfor-
mance.
The swept gain, noise figure and OIP3 results are plotted
on page 1 for an IF of 140MHz and a low side LO. The
conversion gain is greater than 0.7dB across the band with
OIP3 better than 25.5dBm. The single side-band noise
figure is less than 8.8dB across the band.
0
–5
–10
c
–15
–20
a
b
–25
600
700 800 900 1000 1100
FREQUENCY (MHz)
5578 F11
Figure 11. Return Loss Comparison: 740MHz (a),
900MHz (b) and 700MHz to 950MHz (c)
Figure 12. LT5578 Evaluation Board (DC1545A)
5578f
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