Espressif Systems ESP8266EX, Руководство пользователя по оборудованию, Страница: 14 / 48

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Espressif Systems
ESP8266EX
Hardware User Guide
a package size of 0603 or 0805 is needed in circuit design. This capacitor can be used in 0.1uF in
match with capacitor with 0.1uF capacitor with 0402 package.
(Notes: There is no need to add magnetic beads in the design of analog power-supply circuit, for
ESP8266EX’s EMC is in conformity with FCC and CE requirements, and has been approved. )
Figure 5 ESP8266EX AVDD
2.2.2. Power-on Sequence and Power Reset
Power-on sequence
The voltage of the chipset’s WiFi power supply systems is 3.3V, therefore only one rule should be
abide by when you power on the device: Pin7 CH_EN, the power enable pin, should be powered on
at the same time when or after the power supply system is powered on.
Note: If the power management IC is connected with the power-on enable pin CHIP_EN, it can control the
power on-and-off of ESP8266EX by output high and low voltage through its GPIOs. However, pulsed current
might be produced at the same time. In order to delay the transmission of pulsed signal and avoid unstable
current of CHIP_EN, a RC time-delay circuit (R=1k Ω , C=100nF) is needed. There is an internal pull-up in the
CHIP_EN pin, so no external pull-up is needed.
Espressif Systems / Jun 1, 2015 14 48