SAW Components
SAW filter
Short range devices
Series/type:
Ordering code:
Date:
Version:
B3782
B39431B3782Z810
December 20, 2012
2.3
©
EPCOS AG 2012. 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 filter
Data sheet
Application
s
Low-loss RF filter for remote control receivers
s
Balanced and unbalanced operation possible
B3782
433.92 MHz
Features
s
s
s
s
s
s
s
s
s
s
Package size 3.8 x 3.8 x 1.5 mm
3
Package code QCC8B
RoHS compatible
Approximate weight 0.07 g
Package for
Surface Mount Technology
(SMT)
Ni, gold-plated terminals
Lead free soldering compatible with J - STD20C
Passivation layer Elpas
AEC-Q200 qualified component family
Electrostatic Sensitive Device
(ESD)
Pin configuration
1)
s
s
s
s
s
s
1
2
5
6
4,8
3,7
Input ground (recommended) or input
Input (recommended) or input ground
Output (recommended) or output ground
Output ground (recommended) or output
Case - ground
To be grounded
1) The recommended pin configuration usually offers best
suppression of electrical crosstalk. The filter characteris-
tics refer to this configuration.
Please read
cautions and warnings and
important notes
at the end of this document.
2
December 20, 2012
SAW Components
SAW filter
Data sheet
Characteristics
Temperature range for specification:
Terminating source impedance:
Terminating load impedance:
T = –40 ˚C to +105 ˚C
Z
S
=
50
Ω
and matching network
Z
L
=
50
Ω
and matching network
min.
Center frequency
Minimum insertion attenuation
incl. loss in matching elements (Q
L
= 46)
excl. loss in matching elements
Pass band (relative to
α
min
)
433.385 ... 434.455 MHz
1)
433.370... 434.470 MHz
2)
Relative attenuation (relative to
α
min
)
α
rel
10.00 ... 390.00 MHz
390.00 ... 425.00 MHz
425.00 ... 430.00 MHz
430.00 ... 432.80 MHz
432.80 ... 433.00 MHz
435.00 ... 435.40 MHz
435.40 ... 441.50 MHz
441.50 ... 450.00 MHz
450.00 ... 550.00 MHz
550.00 ... 1000.00 MHz
1000.00 ... 2500.00 MHz
Impedance
for pass band matching
3)
Input: Z
IN
= R
IN
|| C
IN
Output: Z
OUT
= R
OUT
|| C
OUT
1)
2)
3)
B3782
433.92 MHz
f
C
α
min
—
typ.
@ 25 ˚C
433.92
max.
—
MHz
—
—
2.2
1.3
2.9
2.0
dB
dB
—
—
1.3
1.4
2.5
3.0
dB
dB
50
45
29
18
7
8
15
35
48
55
45
55
50
33
23
14
12
19
40
53
60
50
—
—
—
—
—
—
—
—
—
—
—
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
—
—
400 || 2.6
400 || 2.6
—
—
Ω
|| pF
Ω
|| pF
433.385 ... 434.400 MHz for extended temperature range –40 ˚C to +125 ˚C.
433.370 ... 434.415 MHz for extended temperature range –40 ˚C to +125 ˚C.
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.
Maximum ratings
Operable temperature range T
Storage temperature range T
stg
DC voltage
Source power
V
DC
P
S
–45/+125 ˚C
–45/+125 ˚C
6
10
3
V
dBm
source impedance 50
Ω
Please read
cautions and warnings and
important notes
at the end of this document.
December 20, 2012
SAW Components
SAW filter
Data sheet
Matching network to 50
Ω
(element values depend on pcb layout and equivalent circuit)
C
p1
=
L
s2
L
s3
=
=
4.7 pF
47 nH
47 nH
4.7 pF
B3782
433.92 MHz
C
p4
=
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 QCC8B package, pinning 2,5 (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
December 20, 2012
SAW Components
SAW filter
Data sheet
ESD protection of SAW filters
B3782
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
December 20, 2012
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