BUTTER07
Contents
Features
- 7th Order Low Pass Butterworth Filter
- Shunt first
- Bourns Inductors, 0603, CS160808 family - inexpensive
- Can mount end launch SMT connectors
- 50 Ohms in/out
Calculator (7 MHz example)
Parts
Cutoff Freq (MHz) | C1/C7 (pF) | C3/C5 (pF) | L2/L6 (uH) | L4 (uH) |
---|---|---|---|---|
4 | 360 | 1500 | 2.4 | 3.9 |
7 | 200 | 820 | 1.5 | 2.2 |
14 | 100 | 390 | 0.68 | 1.1 |
21 | 68 | 270 | 0.47 | 0.75 |
28 | 51 | 200 | 0.36 | 0.56 |
BUTTER07 Design
Values
Cutoff Freq (MHz) | C1/C4 (pF) | C2/C3 (pF) | L1/L3 (uH) | L2 (uH) |
---|---|---|---|---|
4 | 360 | 1500 | 2.4 | 3.9 |
7 | 200 | 820 | 1.5 | 2.2 |
14 | 100 | 390 | 0.68 | 1.1 |
21 | 68 | 270 | 0.47 | 0.75 |
28 | 51 | 200 | 0.36 | 0.56 |
CWAZ Filter
- 2nd-Harmonic-Optimized LPFs by By Ed Wetherhold, W3NQN
- BUTTER07 with extra capacitor for 2nd order harmonic suppression
- L2 and C5 are piggybacked
- Other values are different from the calculator values