Datasheet
Application Note No. 058
Summary
Application Note 11 Rev. 2.1, 2006-10-20
Figure 18 Formula 13
Also worth mentioning is that intermodulation of the reverse biased PIN-diode increases for higher frequencies.
This is in contrast to intermodulation in the on-state of the diode being reduced with increasing frequency.
1.4 Appropriate Diode Selection
In Table 1 intercept-points for forward and reverse bias are summarised for a variety of PIN-diodes. The table
shows that intermodulation robustness in forward-bias might be contrary to the robustness in reverse bias. This is
due to the fact, that
IP
3
in forward-bias decreases with increasing epi-thickness, while IP
3
in reverse-bias
increases. So dependent on the application and system specifications an appropriate choice of the diode is
required.
2 Summary
Reducing inter-modulation distortion in PIN-diode applications requires a careful choice of the appropriate diode
and its operating point. In this note a model has been introduced to estimate third-order distortion in the “on”-state
of the diode from diode parameters given in the data sheet. For the case of a forward biased as well as a reverse
biased diode, maximum power levels are given, which, for reason of moderate inter-modulation, should not be
exceeded.
3 References
• R.Caverly and G. Hiller, “Predict Intercept Points in PIN-Diode Switches”, Microwaves & RF, Dec. 1985
• R. H. Caverly and G. Hiller, “Distortion in Microwave and RF Switches by Reverse Biased PIN-Diodes”,
Proceedings in the IEEE MTTS International Microwave Symposium, Long Beach, Ca, 1989
Table 1 Third-order inter-modulation for a variety of PIN-diodes
1)
1) f = 900 MHz / Input Power 20 dBm
PIN-Diode IP
3
[dBm]
Forward Bias
IP
3
[dBm]
Reverse Bias
τ
L
[µs] r
f
(10 mA) [Ω]
I
F
= 2 mA I
F
= 10 mA V
R
= 15 V
BA592 > 67 > 67 44 0.12 0.4
BAR63-03W 61 > 67 50 0.1 1
BAR65-03W 64 > 67 47 0.08 0.56
BA595 67 > 67 > 73 1.6 4.5
BA885 > 67 > 67 > 73 1.6 0.4
BAR14 63 > 67 > 73 1 8
BAR66 67 > 67 58 0.7 1
BAR64 > 67 > 67 73 1.4 2
AN058_formula_13.vs
d
(13)
0
2
.max,
2Z
V
P
R
rev
=