AN10714_1
© NXP B.V. 2010. All rights reserved.
Application note
Rev. 01 — 26 January 2010
14 of 21
NXP Semiconductors
AN10714
Using the BLF574 in the 88 MHz to 108 MHz FM band
5.
Input and output impedance
The BLF574 input and output impedances are given in
. These are generated from
a first order equivalent circuit of the device and can be used to get the first-pass matching
circuits.
The convention for these impedances is shown in
. They indicate the
impedances looking into half the device.
Table 3.
Input and output impedance per section
Frequency (MHz)
Input (Z
i
)
Output (Z
o
)
25
2.020
−
j26.216
4.987
−
j0.241
50
2.020
−
j13.087
4.947
−
j0.477
75
2.020
−
j8.701
4.882
−
j0.705
100
2.020
−
j6.500
4.794
−
j0.922
125
2.021
−
j5.175
4.685
−
j1.125
150
2.021
−
j4.286
4.559
−
j1.310
175
2.022
−
j3.647
4.418
−
j1.478
200
2.023
−
j3.164
4.266
−
j1.626
225
2.023
−
j2.768
4.106
−
j1.755
250
2.024
−
j2.480
3.941
−
j1.864
275
2.025
−
j2.227
3.773
−
j1.955
300
2.026
−
j2.014
3.605
−
j2.028
325
2.028
−
j1.832
3.439
−
j2.084
350
2.029
−
j1.673
3.275
−
j2.126
375
2.030
−
j1.534
3.116
−
j2.154
400
2.032
−
j1.410
2.962
−
j2.170
425
2.033
−
j1.299
2.814
−
j2.176
450
2.035
−
j1.199
2.673
−
j2.172
475
2.037
−
j1.108
2.538
−
j2.159
500
2.039
−
j1.025
2.410
−
j2.140
Fig 10. Device impedance convention
001aak541
Z
o
Z
i
