Passive Filter Design using PSpice

1. Passive Filter Design
All Rights Reserved Copyright (C) Bee Technologies Corporation 2010 1
Design Services

2. Contents
Slide
#
1. Filter Design
Category..............................................................................
2. Passive Filter Design Flow-
Chart.............................................................
3. Passive Low Pass Filter
Design...............................................................
3.1
Specifications : ..................................................................................
3.2
Calculation : ......................................................................................
.
3.3
Verification : ......................................................................................
.
3.4
Optimization : ....................................................................................
3.5 Elements
3
4
5
5
6
7
8-9
10-11
12
13-15
16-20
21-23
2All Rights Reserved Copyright (C) Bee Technologies Corporation 2009

3. 1.Filter Design Category
Available Filter Types
• Low Pass Filter
• High Pass Filter
• Band Pass Filter
• Band Reject Filter
Approximation
• Butterworth
- No ripple
- Smooth roll-off (rate of 20dB/decade for every pole)
• Chebyshev
- Pass-band ripple specification would be required.
- Steeper roll-of
Topology
• Passive
- High frequency range (> 1 MHz)
- Source and load impedance specifications would be required
• Active
- Low frequency range (1 Hz to 1 MHz)
- Unity-Gain Sallen-Key configuration (see Figure 1.0)
Number of Order
• 2nd
-10th
All Rights Reserved Copyright (C) Bee Technologies Corporation 2010 3

4. 2.Passive Filter Design Flow Chart
All Rights Reserved Copyright (C) Bee Technologies Corporation 2010 4
2. Circuit design and calculation2. Circuit design and calculation
3. Verification3. Verification
4. Optimize with standard capacitor value4. Optimize with standard capacitor value
5. Elements test (± 5%)5. Elements test (± 5%)
Meet the spec?Meet the spec?
No
Yes
Satisfy?Satisfy?
Yes
YESYES
Result :
Filter circuit with all element values
Result :
Filter circuit with all element values
Use Active FilterUse Active Filter
1.Customer’s
specification
1.Customer’s
specification
No

5. 3.Passive Low Pass Filter Design (1/5)
3.1 Specifications :
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 5
Fr e que nc y
1 0 0KHz 1. 0MHz 10 MHz
db ( v ( o ut ) )
- 4 0
- 3 0
- 2 0
- 1 0
0
Figure 1 Low-pass filter response and specification
Pass-band Region
Stop-band Region
Pass-band edge frequency = 1 MHz
Pass-band gain = -3 dB
Stop-band edge frequency = 2.5 MHz
Stop-band gain = -30 dB
•Pass-band edge frequency : 1 MHz (fCutoff)
- Pass-band gain : -3 dB
•Stop-band edge frequency : 2.5 MHz
- Stop-band gain : -30 dB
•Load and Source Condition :
- Source Type : Voltage
- Filter Load Impedance : 50 Ω
- Source Impedance : 50 Ω
STEP1.Customer’s
specification
STEP1.Customer’s
specification

6. 3.Passive Low Pass Filter Design (2/5)
3.2 Calculation :
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 6
Figure 2.1 Low-pass filter circuit with calculated element-values
(Butterworth approximation).
Figure 2.2 Low-pass filter circuit with calculated element-values
(Chebyshev approximation).
0
C 2
1 0 . 6 6 n F
R L 2
5 0
L 1
5 . 6 6 5 u H
1 2
R s
5 0
o u t 3
C 1
1 0 . 6 6 n F
V s o u r c e
0
C 1
5 . 8 7 8 n F
R L
5 0
o u t
L 1
6 . 0 8 7 u H
1 2
L 2
1 4 . 7 u H
1 2
V s o u r c e
R s
5 0
C 2
2 . 4 3 5 n F
•L1=6.087uH
•L2=14.7uH
•C1=5.878nF
•C2=2.435nF
•L1=5.665uH
•C1=10.66nF
•C2=10.66nF
STEP2. Circuit
design and
calculation
STEP2. Circuit
design and
calculation

7. 3.Passive Low Pass Filter Design (3/5)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 7
Figure 3 Response and specification of the calculated circuits.
Fr equ en c y
1 00 KHz 1 . 0MHz 1 0MHz
d b( v ( ou t ) ) d b ( v ( o u t 3 ) )
- 4 0
- 3 0
- 2 0
- 1 0
0
Butterworth (1MHz,-3dB)
Chebyshev : (1MHz,-3dB)
(2.5MHz,-34.8dB)
(2.5MHz,-31.8dB)
3.3 Verification :
• Frequency Response Simulation
Pass-band Ripple (-2.81dB)
•Pass-band edge frequencies : 1 MHz
•Pass-band gains : -3 dB 
•Stop-band edge frequencies : 2.5 MHz
•Stop-band gains : < -30 dB 
•Butterworth Approximation
- No ripple 
- Roll-off rate is 80dB/decade 
•Chebyshev Approximation
- Pass-band ripple : -2.81dB 
- Steeper roll-of with less passive
component 
— Butterworth Approximation
— Butterworth Approximation
STEP3.
Verification
STEP3.
Verification

8. 3.Passive Low Pass Filter Design (4/5)
3.4 Optimization :
- Use standard capacitor values (E-12 Capacitor Values)
- Optimize inductor values
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•L1=6.7 uH
•L2=15.4uH
•C1=5.6nF
•C2=2.2nF
•L1=6.06uH
•C1=10nF
•C2=10nF
Figure 4.1 Low-pass filter circuit with optimized element-values (Butterworth approximation).
Figure 4.2 Low-pass filter circuit with calculated element-values (Chebyshev approximation).
0
C 1
5 . 6 n F
R L
5 0
o u t
L 1
6 . 7 u H
1 2
L 2
1 5 . 4 u H
1 2
V s o u r c e
R s
5 0
C 2
2 . 2 n F
0
C 2
1 0 n F
R L
5 0
L 1
6 . 0 6 u H
1 2
R s
5 0
o u t 3
C 1
1 0 n F
V s o u r c e
STEP4. Optimize with
standard capacitor value
(then verify)
STEP4. Optimize with
standard capacitor value
(then verify)

9. Fr e q ue n c y
10 0 KHz 1. 0MHz 1 0MHz
db( v ( ou t ) ) d b( v ( out 3) )
- 4 0
- 3 0
- 2 0
- 1 0
0
3.Passive Low Pass Filter Design (4/5)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 9
Figure 5 Response and specification of the optimized circuits.
Butterworth (1MHz,-3dB)
Chebyshev : (1MHz,-3dB)
(2.5MHz,-34.3dB)
(2.5MHz,-31.8dB)
3.4 Optimization :
• Frequency Response Simulation
Pass-band Ripple (-2.62dB)
•Pass-band edge frequencies : 1 MHz
•Pass-band gains : -3 dB 
•Stop-band edge frequencies : 2.5 MHz
•Stop-band gains : < -30 dB 
•Butterworth Approximation
- No ripple 
- Roll-off rate is 80dB/decade 
•Chebyshev Approximation
- Pass-band ripple : -2.62dB 
- Steeper roll-of with less passive
component — Butterworth Approximation
— Butterworth Approximation

10. 3.Passive Low Pass Filter Design (5/5)
3.5 Elements test :
- ± 5% test for each element value.
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•L1=6.7 uH (± 5%)
•L2=15.4uH (± 5%)
•C1=5.6nF (± 5%)
•C2=2.2nF (± 5%)
•L1=6.06uH (± 5%)
•C1=10nF (± 5%)
•C2=10nF (± 5%)
Figure 6.1 Low-pass filter circuit with ± 5% of the element-values (Butterworth approximation).
Figure 6.1 Low-pass filter circuit with ± 5% of the element-values (Chebyshev approximation).
0
C 1
5 . 6 n F
R L
5 0
o u t
L 1
6 . 7 u H
1 2
L 2
1 5 . 4 u H
1 2
V s o u r c e
R s
5 0
C 2
2 . 2 n F
0
C 2
1 0 n F
R L
5 0
L 1
6 . 0 6 u H
1 2
R s
5 0
o u t 3
C 1
1 0 n F
V s o u r c e
± 5% ± 5%
± 5% ± 5%
± 5%
± 5% ± 5%
STEP5. Elements test
(± 5%)
STEP5. Elements test
(± 5%)

11. Fr eq ue nc y
100 KHz 1. 0 MHz 10 MHz
d b( v ( out 3 ) )
- 4 0
- 2 0
0
Fr eq uenc y
1 00 KHz 1 . 0 MHz 10 MHz
d b( v ( ou t ) )
- 4 0
- 2 0
0
3.Passive Low Pass Filter Design (5/5)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 11
Figure 7 Response and specification when the element values are error with ±5%.
3.5 Elements test :
• Frequency Response Simulation, compare to -5% and +5% of all element values.
Butterworth
— +5%
— standard values
— -5%
Pass-band gain (-3 dB)
Cutoff frequency : 0.9525M, 1M, 1.0527M
Chebyshev
— +5%
— standard values
— -5%
Pass-band gain (-3 dB) Cutoff frequency : 0.9524M, 1M, 1.0526M

12. V s o u r c e
0
C 2
1 0 n F
R L 2
5 0
L 1
6 . 0 6 u H
1 2
R s 2
5 0
o u t
C 1
1 0 n F
0
C 1
5 . 6 n
R L
5 0
o u t
L 1
6 . 7 u
1 2
L 2
1 5 . 4 u
1 2
V s o u r c e
R s
5 0
C 2
2 . 2 n
3.Passive Low Pass Filter Design
3.6 Result :
• Low-pass filter circuit with all element values.
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 12
•L1=6.7 uH (± 5%)
•L2=15.4uH (± 5%)
•C1=5.6nF (± 5%)
•C2=2.2nF (± 5%)
•L1=6.06uH (± 5%)
•C1=10nF (± 5%)
•C2=10nF (± 5%)
Figure 8.1 Low-pass filter circuit with all element-values (Butterworth approximation).
Figure 8.1 Low-pass filter circuit all element-values (Chebyshev approximation).
± 5% ± 5%
± 5% ± 5%
± 5%
± 5% ± 5%
Result : Filter circuit
with all element values
Result : Filter circuit
with all element values

13. Fr equen c y
10KHz 100KHz 1. 0MHz 10MHz 100MHz
db( v ( out ) )
- 80
- 60
- 40
- 20
0
4.Passive High Pass Filter Design (Example)
Specifications :
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 13
Figure 9 High-pass filter response and specification
Pass-band Region
Stop-band Region
Pass-band edge frequency = 1 MHz
Pass-band gain = -3 dB
Stop-band edge frequency = 0.4 MHz
Stop-band gain = -30 dB
•Pass-band edge frequency : 1 MHz (Cutoff frequency)
- Pass-band gain : -3 dB
•Stop-band edge frequency : 0.4 MHz
- Stop-band gain : -30 dB
•Load and Source Condition :
- Source Type : Voltage
- Filter Load Impedance : 50 Ω
- Source Impedance : 50 Ω

14. V s o u r c e
0
C 2
1 n F
R L 2
5 0
L 1
1 0 . 6 u H
1
2
R s 2
5 0
o u t
C 1
1 n F
0
C 1
4 . 7 n F
R L
5 0
o u t
L 1
4 . 3 u H
1
2
L 2
7 . 1 u H
1
2
V s o u r c e
R s
5 0
C 2
1 . 8 n F
4.Passive High Pass Filter Design (Example)
Result :
• High-pass filter circuit with all element values.
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 14
•C1=4.7nF (± 5%)
•C2=1.8nF (± 5%)
•L1=4.3uF (± 5%)
•L2=7.1uH (± 5%)
•L1=6.06uH (± 5%)
•C1=10nF (± 5%)
•C2=10nF (± 5%)
Figure 9.1 High-pass filter circuit with all element-values (Butterworth approximation).
Figure 9.1 High-pass filter circuit all element-values (Chebyshev approximation).
± 5% ± 5%
± 5% ± 5%
± 5%
± 5%
± 5%

15. Fr e quenc y
100KHz 1. 0MHz 10MHz
db( v ( ou t ) )
- 40
- 20
0
Fr eque nc y
100KHz 1 . 0MHz 10MHz
db( v ( out ) )
- 40
- 20
0
4.Passive High Pass Filter Design (Example)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 15
Figure 10 Response and specification when the element values are error with ±5%.
Elements test :
• Frequency Response Simulation, compare to -5% and +5% of all element values.
Butterworth
— +5%
— standard values
— -5%
Pass-band gain (-3 dB)
Cutoff frequency : 0.952M, 1M, 1.052M
Chebyshev
— +5%
— standard values
— -5%
Pass-band gain (-3 dB) Cutoff frequency : 0.9523M, 1M, 1.0526M
Pass-band Ripple (-2.7dB)

16. •Low end pass band frequency : 1 MHz (fC-L)
- Pass-band gain : -3 dB
•Low end stop band frequency : 0.4 MHz
- Stop-band gain : < -25 dB
•High end pass band frequency : 3 MHz (fC-H)
- Pass-band gain : -3 dB
•High end stop band frequency : 5 MHz
- Stop-band gain : < -25 dB
•Load and Source Condition :
- Source Type : Voltage
- Filter Load Impedance : 50 Ω
- Source Impedance : 50 Ω
Fr e qu e nc y
1. 0MHz 10 MHz3 00 KHz
d b( v ( ou t ) )
- 40
- 30
- 20
- 10
0
5.Passive Band Pass Filter Design (Example)
Specifications :
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 16
Figure 11 Band-pass filter response and specification
Pass-band Region
Low end pass band frequency = 1 MHz
Pass-band gain = -3 dB
Low end stop band frequency = 0.6 MHz
Stop-band gain < -25 dB
Stop-band RegionStop-band Region
High end pass band frequency = 3 MHz
High end stop band frequency = 0.6 MHz

17. L 4
7 . 3 u H
1
2
C 4
1 . 2 n
0
R L
5 0
o u t
V s o u r c e
R s
5 0
L 1
3 u H
1 2
C 1
2 . 7 n
L 2
2 . 8 u H
1
2
L 3
7 . 8 u H
1 2
C 2
2 . 7 n
C 3
1 . 2 n
5.Passive Band Pass Filter Design (Example)
Result (Butterworth approximation) :
• High-pass filter circuit with all element values.
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 17
•L1 = 3uH (± 5%)
•L2 = 2.8uH (± 5%)
•L3 = 7.8uH (± 5%)
•L4 = 7.3uH (± 5%)
•C1 = 2.7nH (± 5%)
•C2 = 2.7nF (± 5%)
•C3 = 1.2nF (± 5%)
•C4 = 1.2nF (± 5%)
Figure 12 Band-pass filter circuit with all element-values (Butterworth approximation).
± 5% ± 5%
± 5% ± 5%
± 5% ± 5%
± 5% ± 5%

18. Fr equenc y
1. 0MHz 10MHz300KHz
db( v ( out ) )
- 40
- 30
- 20
- 10
0
5.Passive Band Pass Filter Design (Example)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 18
Figure 13 Response and specification when the element values are error with ±5%.
Elements test (Butterworth approximation) :
• Frequency Response Simulation, compare to -5% and +5% of all element values.
Butterworth
— +5%
— standard values
— -5%
Pass-band gain (-3 dB)
fC-L: 0.95M, 1M, 1.05M
fC-H: 2.876M, 3M, 3.178M

19. 0
R L
5 0
o u t
V s o u r c e
R s
5 0
L 1
1 2 . 3 u
1 2
C 1
6 8 0 p
L 2
7 u
1
2
L 3
1 2 . 3 u
1 2
C 2
1 . 2 n
C 3
6 8 0 p
5.Passive Band Pass Filter Design (Example)
Result (Chebyshev approximation) :
• High-pass filter circuit with all element values.
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 19
•L1 = 12.3uH (± 5%)
•L2 = 7uH (± 5%)
•L3 = 12.3uH (± 5%)
•C1 = 680pF (± 5%)
•C2 = 1.2nF (± 5%)
•C3 = 680pF (± 5%)
Figure 14 Band-pass filter circuit with all element-values (Chebyshev approximation).
± 5% ± 5%
± 5% ± 5%
± 5% ± 5%

20. Fr equenc y
1. 0MHz 10MHz300KHz
db( v ( out ) )
- 40
- 30
- 20
- 10
0
5.Passive Band Pass Filter Design (Example)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 20
Figure 15 Response and specification when the element values are error with ±5%.
Elements test (Chebyshev approximation) :
• Frequency Response Simulation, compare to -5% and +5% of all element values.
Chebyshev
— +5%
— standard values
— -5%
Pass-band gain (-3 dB)
fC-L: 0.952M, 1M, 1.052M
fC-H: 2.8812M, 3M, 3.184M
Pass-band Ripple (-2.63dB)

21. Fr equenc y
1. 0MHz 10MHz300KHz
db( v ( out ) )
- 40
- 30
- 20
- 10
0
•Low end pass band frequency : 1 MHz (fC-L)
- Pass-band gain : -3 dB
•Low end stop band frequency : 1.4 MHz
- Stop-band gain : < -25 dB
•High end pass band frequency : 3 MHz (fC-H)
- Pass-band gain : -3 dB
•High end stop band frequency : 2.2 MHz
- Stop-band gain : < -25 dB
•Load and Source Condition :
- Source Type : Voltage
- Filter Load Impedance : 50 Ω
- Source Impedance : 50 Ω
6.Passive Band Reject Filter Design (Example)
Specifications :
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 21
Figure 16 Band reject filter response and specification
Pass-band Region
Low end pass band frequency = 1 MHz
Pass-band gain = -3 dB
Low end stop band frequency
= 0.6 MHz
Stop-band gain < -25 dB
Stop-band Region
High end pass band frequency = 3 MHz
High end stop band frequency
= 0.6 MHz
Pass-band Region

22. 0
R L
5 0
V s o u r c e
R s
5 0
L 1
3 . 5 5 u
1 2 o u t
C 1
2 n
L 2
2 . 2 u
1
2
C 2
3 . 3 n
L 3
9 u
1 2
C 3
1 . 2 n
6.Passive Band Reject Filter Design (Example)
Result :
• High-pass filter circuit with all element values.
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 22
•L1 = 3.55uH (± 5%)
•L2 = 2.2uH (± 5%)
•L3 = 9uH (± 5%)
•C1 = 2nH (± 5%)
•C2 = 3.3nF (± 5%)
•C3 = 1.2nF (± 5%)
Figure 17 Band-reject filter circuit with all element-values
± 5%
± 5%
± 5%
± 5%
± 5%
± 5%

23. Fr equenc y
1. 0MHz 10MHz300KHz
db( v ( out ) )
- 40
- 30
- 20
- 10
0
6.Passive Band Reject Filter Design (Example)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2009 23
Figure 13 Response and specification when the element values are error with ±5%.
Elements test :
• Frequency Response Simulation, compare to -5% and +5% of all element values.
Butterworth
— +5%
— standard values
— -5%
Pass-band gain (-3 dB)
fC-L: 0.9457M, 1M, 1.0456M fC-H: 2.873M, 3M, 3.175M