Datasheet

1
(2 f Zp
1 C
)
· · ·
C =
1
Z
(2 f
C
2
p )
· ·
L =
1
Z
(2 f
C
1
p )
· ·
L =
2
1
(2 f Zp
2 C
)· · ·
C =
2
AFE031
www.ti.com SBOS531D –AUGUST 2010–REVISED MAY 2012
The following steps can be used to quickly design the passive passband filter. (Note that these steps produce an
approximate result.)
1. Choose the filter characteristic impedance, Z
C
:
– For –6-db passband attenuation: R
1
= R
2
= Z
C
– For 0-db passband attenuation: R
1
= Z
C
, R
2
= 10 ● Z
C
2. Calculate values for C
1
, C
2
, L
1
, and L
2
using the following equations:
Table 4 and Table 5 shows standard values for common applications.
Table 4. Recommended Component Values for Fourth-Order Passive Bandpass Filter (0-db Passband
Attenuation)
FREQUENCY CHARACTERISTIC
RANGE IMPEDANCE R1 R2 C1 C2 L1 L2
FREQUENCY BAND (kHz) (Ω) (Ω) (Ω) (nF) (nF) (μH) (μH)
CENELEC A 35 to 95 1k 1k 10k 4.7 1.5 1500 4700
CENELEC B, C, D 95 to 150 1k 1k 10k 1.7 1 1200 1500
SFSK 63 to 74 1k 1k 10k 2.7 2.2 2200 2200
Table 5. Recommended Component Values for Fourth-Order Passive Bandpass Filter (–6-db Passband
Attenuation)
FREQUENCY CHARACTERISTIC
RANGE IMPEDANCE R1 R2 C1 C2 L1 L2
FREQUENCY BAND (kHz) (Ω) (Ω) (Ω) (nF) (nF) (μH) (μH)
CENELEC A 35 to 95 1k 1k 1k 4.7 1.5 1500 4700
CENELEC B, C, D 95 to 150 1k 1k 1k 1.7 1 1200 1500
SFSK 63 to 74 1k 1k 1k 2.7 2.2 2200 2200
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