PRELIMINARY PRODUCT SPECIFICATION
nRF24L01 Single Chip 2.4 GHz Radio Transceiver
PERIPHERAL RF INFORMATION
Antenna output
The ANT1 & ANT2 output pins provide a balanced RF output to the antenna. The
pins must have a DC path to VDD, either via a RF choke or via the center point in a
dipole antenna. A load of 100Ω+j175Ω is recommended for maximum output power
(0dBm). Lower load impedance (for instance 50 Ω) can be obtained by fitting a
simple matching network.
Output Power adjustment
SPI RF_SETUP
RF output power
DC current
(RF_PWR)
consumption
11.3 mA
9.0 mA
11
10
01
00
0 dBm
-6 dBm
-12 dBm
-18 dBm
7.5 mA
7.0 mA
Conditions: VDD = 3.0V, VSS = 0V, TA = 27ºC, Load impedance = 100Ω+j175Ω.
Table 14 RF output power setting for the nRF24L01.
Crystal Specification
Frequency accuracy includes initial accuracy (tolerance) and stability over
temperature and aging.
Frequency
CL
ESR max C0max
Frequency accuracy
16MHz
12pF
7.0pF
±60ppm
100 Ω
Table 15 Crystal specification of the nRF24L01
To achieve a crystal oscillator solution with low power consumption and fast start-up
time, it is recommended to specify the crystal with a low value of crystal load
capacitance. Specifying CL=12pF is OK, but it is possible to use up to 16pF.
Specifying a lower value of crystal parallel equivalent capacitance, C0 will also work,
but this can increase the price of the crystal itself. Typically C0=1.5pF at a crystal
specified for C0max=7.0pF.
nRF24L01 sharing crystal with a micro controller.
When using a micro controller to drive the crystal reference input XC1 of the
nRF24L01 transceiver some rules must be followed.
Crystal parameters:
When the micro controller drives the nRF24L01 clock input, the requirement of load
capacitance CL is set by the micro controller only. The frequency accuracy of ±60
ppm is still required to get a functional radio link. The nRF24L01 will load the crystal
by 0.5pF at XC1 in addition to the PBC routing.
Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway
Revision: 1.1
-
Phone +4772898900
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Fax +4772898989
November 2005
Page 29 of 38
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