CC2520_11 Datasheet, PDF (19/133 Pages) Texas Instruments – 2.4 GHZ IEEE 802.15.4/ZIGBEE RF TRANSCEIVER

CC2520 DATASHEET
2.4 GHZ IEEE 802.15.4/ZIGBEE® RF TRANSCEIVER
SWRS068 – DECEMBER 2007
5.10 Low-Current Mode RX
Applications that spend more time waiting for an input
signal than actually receiving it, might benefit from using
the special low-current RX mode. This mode draws less
current at the expense of sensitivity.
Note that when using this mode, neither RSSI nor CCA
is valid. This means that these settings can not be used
in conjunction with STXONCCA, for instance. Also note
that the interferer rejection will drop at stronger input
signal levels compared to when using the regular
recommended settings.
INTERFERER REJECTION (802.15.4 INTERFERER) VS
CARRIER LEVEL WHEN USING RX_LOCUR
60
40
20
0
-87
-78
-69
-60
-51
CARRIER LEVEL (dBm)
Important: The low-current RX mode is only valid from -40 to 85ºC !
5.10.1 Low-Current RX Mode Parameters
T_A =25°C, VDD=3.0 V, f_c=2440 MHz if nothing else stated. All parameters measured on Texas Instruments’ CC2520 EM 2.1 reference design with 50 Ω load.
PARAMETER
CONDITIONS
MIN TYP MAX UNIT
RX current
Wait for sync
18.8
mA
Sensitivity
Interferer Rejection
[2] requires -85 dBm
Wanted signal 3 dB above the sensitivity level, 802.15.4 modulated
interferer at 802.15.4 channels:
±5 MHz from wanted signal. [2] requires 0 dB
±10 MHz from wanted signal. [2] requires 30 dB
-90
dBm
52
dB
54
dB
±20MHz or above.
55
dB
Table 1: Low-current RX mode. Use in addition to regular recommended settings.
Register
RXCTRL
FSCTRL
AGCCTRL2
Setting (hex)
33
12
EB
Comment
Reduces sensitivity and current consumption
Reduces current consumption and valid temperature range
Reduces sensitivity and current consumption
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