User Manual

Revision 1.0 Page 19 of 78
nRF24L01+ Product Specification
5.5 Crystal specifications
Table 11. Crystal specifications
The crystal oscillator startup time is proportional to the crystal equivalent inductance. The trend in crystal
design is to reduce the physical outline. An effect of a small outline is an increase in equivalent serial
inductance Ls, which gives a longer startup time. The maximum crystal oscillator startup time, Tpd2stby =
1.5 ms, is set using a crystal with equivalent serial inductance of maximum 30mH.
An application specific worst case startup time can be calculated as :
Tpd2stby= Ls/30mH *1.5ms if Ls exceeds 30mH.
Note: In some crystal datasheets Ls is called L1 or Lm and Cs is called C1 or Cm.
Figure 3. Equivalent crystal components
Symbol Parameter (condition) Notes Min. Typ. Max. Units
Fxo Crystal Frequency 16 MHz
ΔF Tolerance
a b
a. Frequency accuracy including; tolerance at 25ºC, temperature drift, aging and crystal loading.
b. Frequency regulations in certain regions set tighter requirements for frequency tolerance (For
example, Japan and South Korea specify max. +/- 50ppm).
±60 ppm
C
0
Equivalent parallel capacitance 1.5 7.0 pF
Ls Equivalent serial inductance
c
c. Startup time from power down to standby mode is dependant on the Ls parameter. See Table 16. on
page 24 for details.
30 mH
C
L
Load capacitance 8 12 16 pF
ESR Equivalent Series Resistance 100 Ω
Co
Cs Ls
ESR