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Wi-Fi&Bluetooth Module Series
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3.4.2. Buck Circuit Pins Introduction
The following table describes the pin definition of the internal buck circuit of the module:
Table 6: Definition of Buck Circuit Pins
VIN_LDO_OUT/VIN_LDO is the output and input pins of the buck circuit inside the module, and pin 20 is
the dedicated GND pin of the buck circuit. Because the buck circuit is prone to high-frequency noise,
special attention shall be paid to it. It is recommended to use 2.2
μH inductors such as
TFM201610ALM-2R2MTAA (TDK) and 4.7
μF capacitors to ensure that the traces are as short as
possible and the trace width shall not be less than 0.4mm. At the same time, it is recommended to route
the wires away from sensitive signals.
The following is the buck circuit reference circuit and inductance parameter recommendation table:
Figure 4: Recommended Reference Design Circuit
Table 7: Recommended Inductance Parameters
Pin Name
Pin No.
Description
Min.
Typ.
Max.
VIN_LDO_OUT
21
Internal buck output for the module
-
-
-
VIN_LDO
23
Internal buck input for the module
-
1.35
-
GND
20
Buck circuit dedicated GND pin
Parameter
Recommend
Unit
Inductance
2.2
μH
Tolerance
±20 %
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