Datasheet MT3608 (Aerosemi Technology) - 6

MT3

608
APPLICATION INFORMA TION Setting the Output Voltage Layout Consideration
The internal reference VREF is 0.6V (Typical).The For best performance of the MT3608, the following output voltage is divided by a resistor divider,R1 and guidelines must be strictly followed. R2 to the FB pin. The output voltage is given by  Input and Output capacitors should be placed close to the IC and connected to ground plane R V = V × 1 ( 1 + ) to reduce noise coupling. OUT REF R2  The GND should be connected to a strong ground plane for heat sinking and noise
Inductor Selection
protection. The recommended values of inductor are 4.7 to  Keep the main current traces as possible as 22μH. Small size and better efficiency are the major short and wide. concerns for portable device, such as MT3608 used  SW node of DC-DC converter is with high for mobile phone. The inductor should have low core frequency voltage swing. It should be kept at a loss at 1.2MHz and low DCR for better efficiency. To small area. avoid inductor saturation current rating should be  Place the feedback components as close as considered.

possible to the IC and keep away from the

noisy devices.
Capacitor Selection
Input and output ceramic capacitors of 22μF are recommended for MT3608 applications. For better voltage filtering, ceramic capacitors with low ESR are recommended. X5R and X7R types are suitable because of their wider voltage and temperature ranges.
Diode Selection
Schot ky diode is a good choice for MT3608 because of its low forward voltage drop and fast reverses recovery. Using Schottky diode can get better efficiency. The high speed rectification is also a good characteristic of Schottky diode for high switching frequency. Current rating of the diode must meet the root mean square of the peak current and output average current multiplication as following : I (RMS) ≈ I × I D OUT PEAK The diode’ s reverse breakdown voltage should be larger than the output voltage.
Aerosemi Technology Co., Ltd
6 Document Outline MT3608-P1 MT3608_P2 FUNCTION NAME