SAW Components
Data Sheet B3576
2
May 09, 2001
SAW Components
B3576
315,00 MHz
Low Loss Filter
Data Sheet
Features
q
RF low-loss filter for remote control receivers
q
Package for Surface Mounted Technology
(SMT)
q
Balanced and unbalanced operation possible
Terminals
q
Ni, gold plated
Pin configuration
1
Input
2
Input Ground or balanced input
5
Output
6
Output Ground or balanced output
7
External coupling coil
4,8
Case-Ground
3
to be grounded
Electrostactic Sensitive Device (ESD)
Type
Ordering code
Marking and package ac-
cording too
Packing
according to
B3576
B39321-B3576-U310
C61157A7A56
F61074V8070Z000
Maximum ratings
Operable temperature range
T
A
45/+ 95
C
Storage temperature range
T
stg
45/+ 95
C
DC voltage
V
DC
0
V
Source power
P
S
10
dBm
typ. dimensions in mm, approx. weight 0,1 g
Ceramic package QCC8C
3
May 09, 2001
SAW Components
B3576
315,00 MHz
Low Loss Filter
Data Sheet
Characteristics
Reference temperature:
T
A
= -45 ... 95 C
Terminating source impedance:
Z
S
= 50
and matching network
Terminating load impedance:
Z
L
= 50
and matching network
1)
Temperature dependance of
f
C
:
f
C
(
T
A
) =
f
C
(
T
0
) (1 +
TC
f
(
T
A
-
T
0
)
2
)
2)
Impedance for passband matching bases on an ideal, perfect matching of the SAW filter to
source- and to load impedance (here 50 Ohm). After the SAW filter is removed and input imped-
ance into the input matching / output matching network is calculated.
The conjugate complex value of these characteristic impedances are the input and output imped-
ances for flat passband. For more details, we refer to EPCOS application note #4.
min.
typ.
max.
Center frequency
f
C
--
315,00
--
MHz
(center frequency between 3 dB points)
Minimum insertion attenuation
min
314,90 ... 315,10 MHz
--
3,3
4,8
dB
(including loss in matching coils)
Amplitude ripple (p-p)
314,92 ... 315,08 MHz
--
0,7
2,0
dB
314,90 ... 315,10 MHz
--
1,0
3,0
dB
Relative attenuation (relative to
min
)
rel
10,00 ... 230,00 MHz
65
70
--
dB
230,00 ... 290,00 MHz
40
45
--
dB
290,00 ... 310,00 MHz
50
55
--
dB
310,00 ... 314,10 MHz
42
47
--
dB
315,90 ... 317,00 MHz
21
26
--
dB
317,00 ... 322,00 MHz
38
43
--
dB
322,00 ...1000,00 MHz
55
60
--
dB
Impedance for pass band matching
2)
Input:
Z
IN
=
R
IN
||
C
IN
--
470 || 2,0
--
|| pF
Output:
Z
OUT
=
R
OUT
||
C
OUT
--
470 || 2,0
--
|| pF
Temperature coefficient of frequency
1)
TC
f
--
-0,03
--
ppm/K
2
Frequency inversion point
T
0
10
--
40
C
4
May 09, 2001
SAW Components
B3576
315,00 MHz
Low Loss Filter
Data Sheet
Matching network to 50
(element values depend on pcb layout and equivalent circuit)
C
p1
= 1,2 pF
L
s2
= 82 nH
L
s3
= 82 nH
C
p4
= 1,2 pF
L
k
= 56 nH
Minimising the crosstalk
For a good ultimate rejection a low crosstalk is necessary. Low crosstalk can be realised with
a good RF layout. The major crosstalk mechanism is caused by the "ground-loop" problem.
Grounding loops are created if input-and output transducer GND are connected on the top-side
of the PCB and fed to the system grounding plane by a common via hole. To avoid the common
ground path, the ground pin of the input- and output transducer are fed to the system ground
plane (bottom PCB plane) by their own via hole. The transducers' grounding pins should be
isolated from the upper grounding plane.
A common GND inductivity of 0.5nH degrades the ultimate rejection (crosstalk) by 20dB.
The optimised PCB layout, including matching network for transformation to 50 Ohm, is shown
here. In this PCB layout the grounding loops are minimised to realise good ultimate rejection.
Optimised PCB layout for SAW filters in QCC8C package, pinning 1,5 (top side, scale 1:1)
The bottom side is a copper plane (system ground area). The input and output grounding pins
are isolated and connected to the common ground by separated via holes.
For good contact of the upper grounding area with the lower side it is necessary to place
enough via holes.
5
May 09, 2001
SAW Components
B3576
315,00 MHz
Low Loss Filter
Data Sheet
Normalized frequency response
Normalized frequency response (wideband)
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