Datasheet

PRELIMINARY PRODUCT SPECIFICATION
nRF24L01 Single Chip 2.4 GHz Radio Transceiver
Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.2 Page 30 of 39 March 2006
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 15Ω+j88Ω (simulated values) is recommended for
maximum output power (0dBm). Lower load impedance (for instance 50 Ω) can be
obtained by fitting a simple matching network between the load and ANT1 and
ANT2.
Output Power adjustment
SPI RF-SETUP
(RF_PWR)
RF output power DC current
consumption
11 0 dBm 11.3 mA
10 -6 dBm 9.0 mA
01 -12 dBm 7.5 mA
00 -18 dBm 7.0 mA
Conditions: VDD = 3.0V, VSS = 0V, T
A
= 27ºC, Load impedance = 15Ω+j88Ω.
Table 14 RF output power setting for the nRF24L01.
Crystal Specification
Frequency accuracy includes initial accuracy (tolerance) and stability over
temperature and aging.
Frequency C
L
ESR max C
0max
Frequency accuracy
16MHz 8 – 16 pF
100 Ω
7.0pF ±60ppm
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 a lower value of crystal parallel equivalent capacitance, C
0
will also work, but this can increase the price of the crystal itself. Typically C
0
=1.5pF
at a crystal specified for C
0max
=7.0pF.
The crystal load capacitance, CL, is given by:
''
''
21
21
CC
CC
L
C
+
⋅
= , where C
1
’ = C
1
+ C
PCB1
+C
I1
and C
2
’ = C
2
+ C
PCB2
+ C
I2
C1 and C2 are SMD capacitors as shown in the application schematics. CPCB1 and
CPCB2 are the layout parasitic on the circuit board. CI1 and CI2 are the capacitance seen
into the XC1 and XC2 pin respectively; the value is typical 1pF.