nRF24LE1 Nordic VLSI, nRF24LE1 Datasheet - Page 116

• Manufacturer Part Number: nRF24LE1
• Manufacturer: Nordic VLSI

nRF24LE1 Preliminary Product Specification
13.3
13.3.1
The 16MHz crystal oscillator (XOSC16M) is designed to be used with an AT-cut quartz crystal in parallel
resonant mode. To achieve correct oscillation frequency it is very important that the load capacitance
matches the specification in the crystal datasheet. The load capacitance is the total capacitance seen by
the crystal across its terminals:
C
C
the nRF24LE1 (typically 1pF). C
To ensure a functional radio link the frequency accuracy must be ± 60 ppm or better. The initial tolerance of
the crystal, drift over temperature, aging and frequency pulling due to incorrect load capacitance must all
be taken into account. For reliable operation the crystal load capacitance, shunt capacitance, equivalent
series resistance (ESR) and drive level must comply with the specifications in
recommended to use a crystal with lower than maximum ESR if the load capacitance and/or shunt capaci-
tance is high. This will give faster start-up and lower current consumption.
Revision 1.1
1
PCB2
and C
are stray capacitances on the PCB, while C
2
are ceramic SMD capacitors connected between each crystal terminal and VSS, C
Functional description
16MHz crystal oscillator
Figure 53. Block diagram of 32kHz crystal oscillator
1
and C
C
C
2
2
'
1
P0.1
'
should be of the same value, or as close as possible.
C
C
=
=
LOAD
1
C
C
1
2
116 of 191
+
+
Amplitude
regulator
=
C
C
PIN
Crystal
C
PCB
PCB
C
1
'
1
is the input capacitance on the XC1 and XC2 pins of
'
1
+
2
⋅
C
+
C
+
2
'
C
2
C
'
PIN
PIN
P0.0
C
2
Table 111. on page
PCB1
177. It is
and