ML7345 Family LSIs Hardware Design Manual
10
5. RF matching component values
Table 5.1 shows the measured impedance of the PA_OUT (#20) pin and the LNA_P (#24) pin at operationg
frequency.These impedances are presented as a reference.
Table 5.1 Measured RF impedance.
R + jX [Ω]
TX [PA_OUT(#20)]
RX [LNA_P(#24)]
RF frequency
20dBm
13dBm
10dBm
0dBm
-
ML7345
169MHz
-
3.6 + j16.4
3.6 + j16.4
1.4 + j16.8
627 - j344.7
426MHz
-
60.5 + j25.3
60.5 + j25.3
8.7 + j87.8
264.8 - j414
868MHz
-
22.0 - j69.0
22.0 - j69.0
4.9 - j104.7
92.3 - j190.2
920MHz
-
19.7 - j62.5
19.7 - j62.5
4.6 - j91.2
75.8 - j202
ML7345C
470
～
510MHz
16.9 + j16.7
-
-
-
2.2 - j90.5
ML7345D
868MHz
-
22.0 - j69.0
22.0 - j69.0
4.9 - j104.7
15.1 - j77
920MHz
-
19.7 - j62.5
19.7 - j62.5
4.6 - j91.2
13.7- j72.5
[Note] These component values appropriate for use on the LAPIS Semiconductor’s RF board. It is not
guaranteed to obtain same result on your specific board.
5.1. ANTENNA Tx and Rx direct tie matching circuit
Figure 5.1.1 shows the Antenna maching circuit configuraltions. RF Line layout from LNA_P(24) and PA_OUT(20) to
the Antenna should be the shortest and straight. The REG_PA (#21) pin provides the DC bias to the PA_OUT(#20) pin.
This DC bias should be provided through the inductor (L3). Chebyshev lowpass filter is consist of components L5~L8
and C47~C50,to suppress harmonics.
*Only ML7345D needs to short C41 by 0ohm.
Figure 5.1.1 Transmission matching circuit configurations
C37
C41
L2
L3
C45
C48
L5
C47
L7
C49
Thick line is Zo=50 ohm
C38
L9
ANTENNA
C51
C50
L4
L6
L8
PA_OUT(20)
LNA_P(24)
REG_PA(21)
