Datasheet
Application Note No. 058
Predicting Distortion in PIN-Diode Switches
Application Note 7 Rev. 2.1, 2006-10-20
Figure 8 Formula (6)
Where r
f
<< Z
0
has been assumed. This gives for the intercept-point
Figure 9 Formula (7)
Equations (6) and (7) show that lower third-order distortion with forward biased PIN-diode can be achieved with
diodes of short intrinsic region, and higher carrier lifetime. Another important relationship is that the
IP
3
can be
improved by increasing the diode operating current.
From a given IP
3
level, the intermodulation power at any level of input power can be determined by
Figure 10 Formula
Figure 11 High-frequency equivalent circuit of a PIN-diode switch
AN058_formula_6.vs
d
(6)
3
0
6
1
4
0
2
3
2
4
3
P
DfI
W
Z
v
P
T
IM
=
πτ
AN058_formula_7.vs
d
(7)
2/3
2
2
0
21
3
4
3
=
W
fDI
Z
v
IP
T
τπ
AN058_formula_8.vs
d
(8)
3log2log3log
03
IPPP
IM
−=
AN058_high_F_circuit.vs
d
Z
0
Z
0
P
0