Neoway W30 Hardware User's Manual

Neoway W30 Hardware User's Manual Manual pdf 18 page image

W30 Hardware User GuideCopyright © Neoway Technology Co., Ltd 112.3 Power Supply PinsSignal Pin I/O Function RemarksVDD_3V3_WLAN 38 P Main power supply of WLAN The maximum current can be atleast 800 mA.VDDIO_1V8_WLAN 39 P WLAN I/O interface powersupplyThe maximum current can be atleast 300 mA.VDD_XO_1V8 40 P Power supply for WLAN crystaloscillator to pull upPower supply for the crystaloscillator clock to pull upVDD_3V3_AUDIO 35 P 3.3 V power supply of AUDIO The maximum current can be atleast 300 mA.VDD_1V8_AUDIO 34 P Power supply for AUDIO I/Ointerface 1.8 V power supply of audio2.3.1 Design of WLAN Power SupplyVDD_3V3_WLAN is the main power supply input pin for the Wi-Fi function of the module. Its inputvoltage ranges from 3.14 V to 3.46 V and the typical value is 3.3 V. It is recommended that the maximuminput current of the external power supply chipset should be at least 800 mA, which can fulfill therequirements for current in all kinds of work modes. The power supply is a critical path to module'sperformance and stability. The reference design of the WLAN power supply is shown as below:Figure 2-2 Reference design of 3.3 V WLAN power supplyENINNCOUTFBGNDWLAN_3V3_ENVMAINVDD_3V3_WLAND1 C1C2 C3 C4 C5L1R1R22.2uH47uF47uF 10uF 1uF 0.1uF135KΩ30KΩC6100pFBL9309In Figure 2-2, use TVS at D1 to enhance the performance of the module during a burst. SMF5.0AG isrecommended. A large bypass tantalum capacitor (47 μF) is expected at C2 to reduce voltage drops duringbursts together with C3 (10 μF ceramics capacitor). In addition, add 0.1 μF and 100 pF filter capacitors toenhance the stability of the power supply.VDDIO_1V8_WLAN and VDD_XO_1V8 are respectively the internal I/O power supply of the moduleand the pullup power supply of the WLAN crystal oscillator. The level of VDDIO must be same as the I/Olevel of the host, and the maximum work current should be at least 300 mA.Figure 2-3 shows the power on/off sequence of the WLAN.