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Mini-Circuits ADTT4-1
The FSA3157 is also tested with the ADTT4-1 as these transformers look very promising from their insertion and return loss plots supplied by minicircuits and from the standalone transformer IP3 measurement.
| FSA3157 + ADTT4-1 + 74AC04 |
Vdd = 7.0V, Vbias = 2.5V |
Best bias |
| Band |
BPF |
mixer |
MDS -dBm |
IF rej |
spur |
mixer IIP3 (dBm) @ 20KHz spacing |
Bias |
IIP3 |
| IL |
CL |
- |
+ |
|
avg |
-6 |
-3 |
0 |
+3 |
+5 |
|
0 |
| -dB |
-dB |
BPF |
BPF |
-dB |
dB |
dBm |
dBm |
dBm |
dBm |
dBm |
V |
dBm |
| 160 |
3,3 |
5,04 |
133 |
129 |
50,0 |
|
|
|
45,9 |
|
|
3,0 |
46,7 |
| 80 |
1,4 |
5,00 |
133 |
131 |
51,2 |
|
45,7 |
47,2 |
48,7 |
48,7 |
46,2 |
2,2 |
48,7 |
| 40 |
2,3 |
5,04 |
133 |
130 |
52,4 |
|
|
|
44,9 |
|
|
2,2 |
44,9 |
| 30 |
3,4 |
5,08 |
133 |
129 |
52,0 |
|
|
|
43,0 |
|
|
2,5 |
43,0 |
| 20 |
3,4 |
5,08 |
133 |
129 |
53,2 |
|
|
|
41,9 |
|
|
2,6 |
41,9 |
| 17 |
3,0 |
5,04 |
133 |
129 |
55,2 |
|
|
|
40,3 |
|
|
2,7 |
40,3 |
| 15 |
3,9 |
5,04 |
133 |
128 |
56,8 |
-3,1 |
|
|
39,4 |
|
|
2,8 |
39,4 |
| 12 |
3,7 |
5,04 |
133 |
129 |
44,0 |
|
|
|
38,3 |
|
|
2,5 |
38,3 |
| 10 |
2,3 |
5,08 |
133 |
130 |
38,0 |
|
|
|
37,3 |
|
|
2,8 |
37,3 |
| 6 |
|
5,32 |
132 |
|
51,2 |
|
|
|
36,0 |
|
|
3,0 |
36,0 |
| 4 |
|
5,80 |
129 |
|
26,8 |
|
|
|
35,1 |
|
|
2,5 |
35,1 |
Conversion loss is similar to the TT4-1A configuration. The ADTT4-1's are the first transformers to do really well on 160M. The standalone IP3 measurement of this transformer already predicted this more or less.
Average spur level with the ADTT4-1 is excellent at -3.1dB. Note that this applies to a mixer adjusted for best RF-IF isolation, so nothing special was done to minimize the spur level. RF-IF isolation is good at -50dB on all bands, if band specific adjustments are made. The levels in the table are for the best isolation on 15M.
With the bias point at 2.5V it could not be improved significantly with band specific bias point adjustments.
On the higher bands the IP3 deteriorates like with the TT4-1A, ruling out an all band > +40dBm mixer with this configuration.
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