ML7406 Family LSIs Hardware Design Manual
FEXL7406DG-01
11
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 868MHz. These
impedances were measured at LSI pins without matching circuits. Please adjust matching circuit so that the
impedance at the antenna edge is 50 Ω. These impedances are presented as a reference.
Table 5.1 Measured RF impedance at 868MHz operation
R+jX [Ω]
Tx (PA_OUT pin)
13dBm
19.23 – j43.57
10dBm
T.B.D.
0dBm
14.82 – j53.80
Rx (LNA_P pin)
34.35 – j112.6
[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. Transmission matching circuit
Figure 6.1.1 shows the transmission maching circuit configuraltions. The REG_PA (#28) pin provides the DC
bias to the PA_OUT(#27) pin. This DC bias should be provided through the inductor (L6). The parallel resonant
circuit (L8,C48) and series resonant circuits (L9,C49 and L11,C51) are the trap filter to suppress harmonics.
Figure 5.1.1 Transmission matching circuit configurations
[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.
PA_OUT (#20)
L3
4.1nH
C45
100pF
L6
6.2nH
L5
3.6nH
C47
0.9pF
C48
1.0pF
C44
2.4pF
REG_PA (#21)
C38
100pF
C37
1µF
Blue line is 50
Ω
line
ANTENNA