Low Pass LC Filters:
A lowpass filter provides good transmission at frequencies below the cut-off frequency (Fc) and suppresses transmission at higher frequencies. An abrupt change from the “pass” to “stop” condition is not feasible in real filters. Therefore, a reasonable “guardband” is provided by specifying a stopband frequency Fr where a specific level of rejection Ar is to be achieved and maintained.
More lowpass filters are used than any other type for suppression of harmonic pf spurious outputs from transmitters or other RF signals. Lowpass filters are also used for protection of sensitive receiving equipment from strong signals at higher frequencies.
Lowpass filters can be supplied as lumped, semi-lumped constant construction or distributed elements construction depending on frequency. Good passband quality may be defined as low reflection, low insertion loss and flat time delay. In genera, increasing selectivity results in decreasing passband.
|
OPT |
Freq. |
PassBand |
I.L. |
Ripple |
Rejection Band |
Zin |
VSWR |
Power |
Temperat. |
Package |
|
MHz |
MHz |
dB |
dB |
db |
MHz |
W |
|||||
|
LP9860* |
4.200 |
.200to4.20 |
0.5 |
0.5 |
37 |
5.50to10.0 |
75 |
20 db |
|
0 / + 50 |
47.3X28X12.71 |
|
LP4213* |
43.000 61.500 88.000 |
30.0to43.0 43.0to61.5 61.5to88.0 |
0.6 0.6 0.6 |
0.6 0.6 0.6 |
47 47 47 |
60 86 123 |
50 50 50 |
16.5dB 16.5dB 16.5 db |
70 70 70 |
-55/ +100 -55/ +100 -55/ +100 |
78.2X63.5X18.8 |
|
LP4214 |
43.000 |
30.0to43.0 |
0.6 |
0.6 |
50 |
60 to 800 |
50 |
1.35:1 |
8 |
-55/ +100 |
28X9.2X10.4 |
|
LP4215 |
61.500 |
61.5to88.0 |
0.6 |
0.6 |
50 |
86 to 800 |
50 |
1.35:1 |
8 |
-55/ +100 |
28X9.2X10.4 |
|
LP4216 |
88.000 |
DC to 174 |
0.6 |
0.6 |
50 |
123 to 800 |
50 |
1.35:1 |
8 |
-55/ +100 |
28X9.2X10.4 |
|
LP9568 |
174.000 |
100 to 174 |
0.1 |
0.2 |
60 |
@ 320 to 500 |
50 |
1.4:1 |
|
-20/ +60 |
81X21X30 |
| LP9573 |
174.000 |
5,000 |
0.5 |
0.5 |
30 |
@ 200 to 225 |
50 |
1.4:1 |
200 |
-50/ +100 |
134X25X25SMA |
|
LP9574 |
225.000 |
174 to 225 |
0.5 |
0.5 |
50 |
@ 348 to 390 |
50 |
1.4:1 |
200 |
-50/ +100 |
134X25X25SMA |
|
LP9575 |
4000.000 |
225 to 500 |
0.5 |
0.5 |
30 |
@ 450 to 500 |
50 |
1.4:1 |
200 |
-50/ +100 |
134X25X25SMA |
|
LP9576 |
470.000 |
400 to 470 |
0.5 |
0.5 |
50 |
@ 800 to 900 |
50 |
1.4:1 |
200 |
-50/ +100 |
134X25X25SMA |
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