
308MHz/315MHz/418MHz/433.92MHz
Low-Power, FSK Superheterodyne Receiver
Typical Operating Characteristics (continued)
(Typical Application Circuit, V DD = 3.0V, f RF = 433.92MHz, IF BW = 280kHz, data rate = 4kbps Manchester encoded, frequency
deviation = ±50kHz, BER = 0.2%, T A = +25°C, unless otherwise noted.)
INPUT IMPEDANCE
S11 SMITH PLOT OF R FIN
70
vs. INDUCTIVE DEGENERATION
MAX7042 toc20
-150
f RF = 315MHz
60
50
-160
-170
433.92MHz
40
30
REAL IMPEDANCE
IMAGINARY
-180
-190
IMPEDANCE
20
-200
INPUT IMPEDANCE
vs. INDUCTIVE DEGENERATION
1
10
INDUCTIVE DEGENERATION (nH)
PHASE NOISE
vs. OFFSET FREQUENCY
100
90
f RF = 433.92MHz
MAX7042 toc21
-100
-70
f RF = 315MHz
80
-80
70
IMAGINARY
-110
-90
f RF = 433.92MHz
60
IMPEDANCE
50
-120
-100
40
30
20
REAL IMPEDANCE
-130
-140
-110
-120
-130
1
10
100
100
1k
10k
100k
1M
10M
INDUCTIVE DEGENERATION (nH)
OFFSET FREQUENCY (Hz)
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