Atmel ATA3741 Series, Operating

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4899B–RKE–10/06
ATA3741
Figure 3-2. Input Matching Network With SAW Filter
Figure 3-3. Input Matching Network Without SAW Filter
Please note that for all coupling conditions ( Figure 3-2 and Figure 3-3 ), the bond wire inductivity
of the LNA ground is compensated. C3 forms a series resonance circuit together with the bond
wire. L = 25 nH is a feed inductor to establish a DC path. Its value is not critical but must be large
enough not to detune the series resonance circuit. For cost reduction, this inductor can be easily
printed on the PCB. This configuration improves the sensitivity of the receiver by about 1 dB to
2 dB.
IN
IN_GND
OUT
OUT_GND
CASE_GND
B3555
ATA3741
C3
22p
L
25n
C16
100p
C17
8.2p
L3
27n
TOKO LL2012
27NJ
C2
8.2 pF
L2
TOKO LL2012
F33NJ
33n
1
2
3, 4 7, 8
5
6
8
9
RF
IN
f
RF
= 433.92 MHz
LNAGND
LNA_IN
IN
IN_GND
OUT
OUT_GND
CASE_GND
B3551
ATA3741
C3
47p
L
25n
C16
100p
C17
22p
L3
47n
TOKO LL2012
F47NJ
C2
10 pF
L2
TOKO LL2012
F82NJ
82n
1
2
3, 4 7, 8
5
6
8
9
RF
IN
f
RF
= 315 MHz
LNAGND
LNA_IN
ATA3741
15p 25n
3.3p
100p
22n
TOKO LL2012
F22NJ
8
9
RF
IN
f
RF
= 433.92 MHz
LNAGND
LNA_IN
ATA3741
33p 25n
3.3p
100p
39n
TOKO LL2012
F39NJ
8
9
RF
IN
f
RF
= 315 MHz
LNAGND
LNA_IN