SAW Components
SAW RF filter
Short range devices
Series/type:
Ordering code:
Date:
Version:
B3575
B39431B3575U310
April 01, 2008
2.0
©
EPCOS AG 2008. Reproduction, publication and dissemination of this data sheet, enclosures
hereto and the information contained therein without EPCOS’ prior express consent is prohibited.
SAW Components
SAW RF filter
Data sheet
Application
s
Low-loss RF filter for remote control receivers
s
Balanced and unbalanced operation possible
B3575
433.92 MHz
Features
s
s
s
s
s
s
s
s
s
s
Package size 5.0 x 5.0 x 1.35 mm
3
Package code QCC8C
RoHS compatible
Approximate weight 0.1 g
Package for
Surface Mount Technology
(SMT)
Ni, gold-plated terminals
Lead free soldering compatible with J - STD20C
Passivation layer Protec
AEC-Q200 qualified component family
Electrostactic Sensitive Device
(ESD)
Pin configuration
s
s
s
s
s
s
s
1
2
5
6
7
4, 8
3
Input
Input ground or balabced input
Output
Output ground or balanced output
External coupling coil
Case-Ground
to be grounded
Please read
cautions and warnings and
important notes
at the end of this document.
2
April 01, 2008
SAW Components
SAW RF filter
Data sheet
Characteristics
Temperature range for specification:
Terminating source impedance:
Terminating load impedance:
T = –40 ˚C to +95 ˚C
Z
S
=
50
Ω
and matching network
Z
L
=
50
Ω
and matching network
min.
Center frequency
(center frequency between 3 dB pionts)
f
C
—
typ.
@ 25 ˚C
433.92
max.
—
B3575
433.92 MHz
MHz
Minimum insertion attenuation
α
min
433.83 ... 434.01 MHz
(incl. loss in matching elements)
Amplitude ripple
(p-p)
433.83 ... 434.01 MHz
433.81 ... 434.03 MHz
α
rel
Relative attenuation
(relative to
α
min
)
10.00 ... 300.00 MHz
300.00 ... 400.00 MHz
400.00 ... 424.00 MHz
424.00 ... 430.00 MHz
430.00 ... 433.02 MHz
434.92 ... 439.00 MHz
439.00 ... 1000.00 MHz
Impedance
for pass band matching
1)
Input: Z
IN
= R
IN
|| C
IN
Output: Z
OUT
= R
OUT
|| C
OUT
Temperature coefficient of frequency
2)
TC
f
T
0
Frequency inversion point
1)
—
3.4
4.7
dB
—
—
0.5
0.7
2.0
3.0
dB
dB
60
50
60
55
40
30
58
70
55
65
60
45
35
63
—
—
—
—
—
—
—
dB
dB
dB
dB
dB
dB
dB
—
—
—
10
360 || 2.0
360 || 2.1
–0,03
—
—
—
—
40
Ω
|| pF
Ω
|| pF
ppm/K
2
°C
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 removal of the SAW filter the input impedance of the input and output match-
ing network is calculated. The conjugate complex value of these characteristic impedances are the input and
output impedances for flat passband. For more details we refer to EPCOS application note #4.
Temperature dependance of f
C
: f
C
(T
A
) = f
C
(T
0
) (1 + TC
f
(T
A
- T
0
)
2
)
Maximum ratings
Operable temperature range
Storage temperature range
DC voltage
Source power
Source power
T
A
T
stg
V
DC
P
S
P
S
–45/+125
–45/+125
6
10
12
3
˚C
˚C
V
dBm
dBm
source impedance 50
Ω
duty cycle 1:10
Please read
cautions and warnings and
important notes
at the end of this document.
April 01, 2008
SAW Components
SAW RF filter
Data sheet
Matching network to 50
Ω
(element values depend on pcb layout and equivalent circuit)
C
p1
= 3.3 pF
L
s2
= 47 nH
L
s3
= 47 nH
C
p4
= 3.3 pF
L
k
= 33 nH
B3575
433.92 MHz
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.
Please read
cautions and warnings and
important notes
at the end of this document.
4
April 01, 2008
SAW Components
SAW RF filter
Data sheet
ESD protection of SAW filters
B3575
433.92 MHz
SAW filters are
Electro Static Discharge
sensitive devices. To reduce the probability of damages
caused by ESD, special matching topologies have to be applied.
In general, “ESD matching” has to be ensured at that filter port, where electrostatic discharge is
expected.
Electrostatic discharges predominantly appear at the antenna input of RF receivers. Therefore
only the input matching of the SAW filter has to be designed to short circuit or to block the ESD
pulse.
Below two figures show recommended “ESD matching” topologies.
Depending on the input impedance of the SAW filter and the source impedance, the needed
component values have to be determined from case to case.
Ls3
MLC1
Ls3
to output
matching
to output
matching
Lp2
Dp1
Lp2
Fig. 1 MLC varistor plus ESD matching
Fig. 2 Suppressor diode plus ESD matching
In cases where minor ESD occur, following simplified “ESD matching” topologies can be used
alternatively.
Ls2
to output
matching
Cs1
to output
matching
Lp1
Lp2
Fig. 3 shunt L – series L matching
Fig. 4 series C – shunt L matching
Effectiveness of the applied ESD protection has to be checked according to relevant industry
standards or customer specific requirements.
For further information, please refer to EPCOS Application report:
“ESD
protection for SAW filters”.
This report can be found under www.epcos.com/rke. Click on
“data sheets” and then “Applications” under category “Further information”.
Please read
cautions and warnings and
important notes
at the end of this document.
5
April 01, 2008
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