Espressif Systems ESP8266 Series Hardware Design Manuallines page 11

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1.4.1.2. Analog Power Supply
ESP8266EX has five analog pins for power supply, including Pin1, Pin3, Pin4 that are the
power supply for internal PA and LNA; and Pin29, Pin30 for the internal PLL. The operating
voltage for analog power supply pins is 2.5V ~ 3.6V.
Note that the power supply channel might be damaged due to the sudden increase of
current when ESP8266EX is transmitting analog signals. Therefore, an additional 10 μF
capacitor with a 0603 or 0805 package is needed to match the 0.1 μF capacitor.
�� Note:
• ESP8266EX's EMC is in conformity with FCC and CE requirements. There is no need to add ferrite
beads in the analog power-supply circuit.
• When using a single power supply, the recommended output current is 500 mA.
It is suggested that users add an ESD tube at the power entrance.
•
Espressif
CHIP_EN
XPD_DCDC
ESP8266EX
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Figure 1-4. ESP8266EX Digital Power Supply Pins
VDD33
VDD33
C5 C3
10uF 0.1uF
GND
GND
ANT1
C4
1 WIFI_ANT
2
L1
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Figure 1-5. ESP8266EX AVDD
SD_DATA_2
17
VDDPST
U2
C6
1uF 1uF(NC)
GND
L3 4.3nH
GND
C7
TBD(NC)
GND
2.2nH
L2
7 " /30
1. ESP8266EX
VDD33
10pF
GND
C8
R1
12K±1%
GND
1
VDDA
2
LNA
3
VDD3P3
4
VDD3P3
5
VDD_RTC
2018.12