MICRF009 データシートの表示（PDF） - Micrel
部品番号
コンポーネント説明
メーカー
MICRF009 Datasheet PDF : 16 Pages
| |||
Micrel
MICRF009
Additional Applications Information
In addition to the basic operation of the MICRF009, the
following enhancements can be made. In particular, it is
strongly recommended that the antenna impedance is
matched to the input of the IC.
Antenna Impedance Matching
As shown in Figure 7, and Table 4, the antenna pin input
impedance is frequency dependent.
The ANT pin can be matched to 50Ω with an L-type circuit
as shown in Figure 3. That is, a shunt inductor from the
antenna input to ground and another in series from the
antenna input to the ANT pin.
Inductor values may be different from Table 4, depending
on PCB material, PCB thickness, ground configuration, and
how long the traces are in the layout. Values shown were
characterized for a 0.031” thickness, FR4 board, solid
ground plane on bottom layer, and very short traces.
MuRata and Coilcraft wire-wound 0603 or 0805 surface
mount inductors were tested, however, any wire-wound
inductor with high SRF (self-resonance frequency) should
do the job.
Shutdown Function
Duty-cycled operation of the MICRF009 (often referred to
as polling) is achieved by turning the MICRF009 on and off
via the SHUT pin. The shutdown function is controlled by a
logic state applied to the SHUT pin. When VSHUT is high,
the device goes into low-power standby mode. This pin is
pulled high internally, and it must be externally pulled low
to enable the receiver.
j25
j100
Frequency
(Mhz)
300
305
310
315
320
325
330
335
340
345
350
355
360
365
370
375
380
385
390
395
400
405
410
415
420
425
430
435
440
S11
Mag, angle
Z11, ohms
0.944,-36.65 14.45-j150
0.940,-37.499 14.84-j145
0.942,-37.579 14.28-j145
0.945, -37.66 13.48-j145
0.943,-38.237 13.58-j143
0.942, -38.814 13.43-j140
0.94, -39.39
13.5-j138
0.938, -39.967 13.59-j136
0.937, -40.544 13.44-j134
0.935, -41.12 13.51-j132
0.933, -41.697 13.57-j130
0.931, -42.274 13.62-j123
0.93, 42.85
13.48-j126
0.928, -43.427 13.52-j124
0.926, -44.004 13.57-j122
0.925, -44.581 13.42-j120
0.923, -45.157 13.46-j118
0.921, -45.734 13.49-j117
0.92, -46.311 13.35-j115
0.917, -46.729 13.6-j114
0.914, -47.148 13.89-j113
0.912, -47.566 14.00-j112
0.909, -47.985 14.25-j110
0.907, -48.403 14.34-j109
0.906, -48.797 14.28-j108
0.909, -49.152 13.63-j107
0.911, -49.507 13.15-j107
0.911, -49.925 12.94-j106
0.904, -50.571 13.66-j104
Table 4
C3, pF L2, nH
2.2
47
2.2
47
2.2
47
2.2
47
2
47
1.8
47
1.8
47
1.8
43
1.8
43
1.8
43
2
39
2.2
36
2.2
36
2
36
1.8
36
2.2
33
2
33
1.8
33
1.8
33
1.8
33
2
30
1.8
30
1.8
30
2.2
27
2
27
2
27
1.8
27
1.8
27
1.8
27
0
50
∞
–j25
–j100
Figure 7
January 18, 2005
12
M9999-011805
(408) 955-1690
Share Link: 