Data Sheet

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3. Functional Description
3.3.2. External Clock Requirements
An externally generated clock is available with the frequency ranging from 24 MHz to 52
MHz. The following characteristics are expected to achieve good performance of radio.
3.4. Radio
ESP8266EX radio consists of the following blocks.
• 2.4 GHz receiver
• 2.4 GHz transmitter
•
High speed clock generators and crystal oscillator
• Real time clock
• Bias and regulators
• Power management
3.4.1. Channel Frequencies
The RF transceiver supports the following channels according to IEEE802.11b/g/n
standards.
Table 3-2. High Frequency Clock Specifications
Parameter
Symbol
Min
Max
Unit
Frequency
FXO
24
52
MHz
Loading capacitance
CL
－
32
pF
Motional capacitance
CM
2
5
pF
Series resistance
RS
0
65
Ω
Frequency tolerance
ΔFXO
-15
15
ppm
Frequency vs temperature (-25°C ~ 75°C)
ΔFXO,Temp
-15
15
ppm
Table 3-3. External Clock Reference
Parameter
Symbol
Min
Max
Unit
Clock amplitude
VXO
0.2
1
Vpp
External clock accuracy
ΔFXO,EXT
-15
15
ppm
Phase noise @1kHz offset, 40 MHz clock
－
－
-120
dBc/Hz
Phase noise @10kHz offset, 40 MHz clock
－
－
-130
dBc/Hz
Phase noise @100kHz offset, 40 MHz clock
－
－
-138
dBc/Hz
Espressif
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2017.04