EVAL-ADF7021DBZ5 Datasheet, PDF (20/64 Pages) Analog Devices – High Performance Narrow-Band Transceiver IC

ADF7021
90
80
70
60
50
40
30
20
10
0
–10
–22 –18 –14 –10 –6
RF FREQ = 868MHz
WANTED SIGNAL
(10dB ABOVE SENSITIVITY
POINT) = 2FSK,
f_DEV = 4kHz,
DATA RATE = 9.8kbps
BLOCKER = 2FSK,
f_DEV = 4kHz,
DATA RATE = 9.8kbps
V_DD = 3.0V
TEMPERATURE = 25°C
–2 0 2 6 10 14 18 22
FREQUENCY OFFSET (MHz)
Figure 23. Wideband Interference Rejection
–20
RSSI
READBACK LEVEL
–40
–60
–80
–100
–120
ACTUAL RF INPUT LEVEL
–140
–122.5 –112.5 –102.5 –92.5 –82.5 –72.5 –62.5 –52.5 –42.5
RF INPUT (dBm)
Figure 24. Digital RSSI Readback Linearity
70
CALIBRATED RF FREQ = 430MHz
EXTERNAL VCO INDUCTOR
60
DATA RATE = 9.6kbps
TEMPERATURE = 25°C, V_DD = 3.0V
50
40
30
UNCALIBRATED
20
10
0
–10
429.80 429.85 429.90 429.95 430.00 430.05 430.10 430.15 430.20
RF FREQUENCY (MHz)
Figure 25. Image Rejection, Uncalibrated vs. Calibrated
Data Sheet
–100
–102
–104
–106
RF FREQ = 860MHz
2FSK MODULATION
DATA RATE = 9.6kbps
IF BW = 25kHz
V_DD = 3.0V
TEMPERATURE = 25°C
–108
–110
–112
DISCRIMINATOR BANDWIDTH =
2× FSK FREQUENCY DEVIATION
–114
–116 _{DISCRIMINATOR BANDWIDTH =}
1× FSK FREQUENCY DEVIATION
–118
0
0.2
0.4
0.6
0.8
1.0
1.2
MODULATION INDEX
Figure 26. 2FSK Sensitivity vs. Modulation Index vs. Correlator
Discriminator Bandwidth
0
–1
THRESHOLD DETECTION
–2
VITERBI DETECTION
–3
–4
–5 _{3FSK MODULATION}
V_DD = 3.0V, TEMP = 25°C
DATA RATE = 9.6kbps
–6 _{fDEV = 2.4kHz}
RF FREQ = 868MHz
IF BW = 18.75kHz
–7
–120 –118 –116 –114 –112
TYPICALLY
3dB
–110 –108
–106
–104
–102
–100
INPUT POWER (dBm)
Figure 27. 3FSK Receiver Sensitivity Using Viterbi Detection and
Threshold Detection
+3
+1
0
–1
–3
RF I/P LEVEL = –70dBm
DATA RATE = 9.7kbps
f_DEV (inner) = 1.2kHz
22452 ACQS
IF BW = 25kHz
POST DEMOD BW = 12.4kHz
M 50µs
Figure 28. 4FSK Receiver Eye Diagram Measure Using the Test DAC Output
Rev. B | Page 20 of 64