MICRF002BM 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
MICRF002BM Datasheet PDF : 16 Pages
| |||
MICRF002/RF022
Additional Applications Information
In addition to the basic operation of the MICRF002 the
following enhancements can be made. In particilar it is
strongly recommended that the antenna impedance is
matched to the input of the IC.
Antenna Impedance Matching
As shown in table 4 the antenna pin input impedance is
frequency dependant.
The ANT pin can be matched to 50 Ohms with an L-type
circuit. That is, a shunt inductor from the RF input to ground
and another in series from the RF input to the antenna pin.
Inductor values may be different from table depending on
PCB material, PCB thickness, ground configuration, and how
long the traces are in the layout. Values shown were charac-
terized 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 MICRF002 (often referred to as
polling) is achieved by turning the MICRF002 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, it must be externally pulled low to enable the
receiver.
LSERIES
LSHUNT
j25
j100
Micrel
Frequency
(MHz)
ZIN( )
Z11
S11
LSHUNT (nH)
LSERIES (nH)
300
12– j166 0.803– j0.529
15
72
305
12– j165 0.800– j0.530
15
72
310
12 – j163 0.796– j0.536
15
72
315
13 – j162 0.791– j0.536
15
72
320
12 – j160 0.789– j0.543
15
68
325
12 – j157 0.782– j0.550
12
68
330
12 - j155 0.778– j0.556
12
68
335
12 – j152 0.770– j0.564
12
68
340
11 - j150 0.767– j0.572
15
56
345
11 – j148 0.762– j0.578
15
56
350
11 – j145 0.753– j0.586
12
56
355
11 – j143 0.748– j0.592
12
56
360
11 – j141 0.742– j0.597
10
56
365
11 – j139 0.735– j0.603
10
56
370
10 – 137 0.732– j0.612
12
47
375
10 – j135 0.725– j0.619
12
47
380
10 – j133 0.718– j0.625
10
47
385
10 – j131 0.711– j0.631
10
47
390
10 – j130 0.707– j0.634
10
43
395
10 – j128 0.700– j0.641
10
43
400
10 – j126 0.692– j0.647
10
43
405
10 – j124 0.684– j0.653
10
39
410
10 – j122 0.675– j0.660
10
39
415
10 – j120 0.667– j0.667
10
39
420
10 – j118 0.658– j0.673
10
36
425
10 – j117 0.653– j0.677
10
36
430
10 – j115 0.643– j0.684
10
33
435
10 – j114 0.638– j0.687
10
33
440
8 – j112 0.635– j0.704
8.2
33
Table 4. Input Impedance Versus Frequency
0
50
∞
–j25
March 2003
–j100
11
MICRF002/RF022
Share Link: 