Overview

The MT3608 is a 6-pin SOT23-6 constant frequency, 6-terminal step-up (boost) DC-DC converter manufactured by Aerosemi. Operating at a high switching frequency of 1.2 MHz, it allows the use of tiny external inductors and capacitors while achieving up to 97% power efficiency.

Most commonly sold as a tiny 36 mm×17 mm36\text{ mm} \times 17\text{ mm} blue breakout module featuring a 25-turn precision trimmer potentiometer, it takes input voltages from 2.0V2.0\text{V} to 24.0V24.0\text{V} (such as single LiPo cells, 5V USB power, or AA batteries) and steps them up to an adjustable output voltage of up to 28.0V28.0\text{V}.

Quick reference

Input Voltage (VIN)2.0 V to 24.0 V DC
Output Voltage (VOUT)Adjustable from VINVIN up to 28.0 V DC
Max Peak Switch Current2.0 A
Switching Frequency1.2 MHz fixed
Max EfficiencyUp to 97%
Feedback Reference Voltage0.6 V (±2%\pm 2\%)
PackageSOT23-6 IC / Breakout Module

Pinout & Module Terminals

SOT23-6 Package IC

text
         ┌───┴───┐
     SW 1│       │6 NC
    GND 2│       │5 IN
     FB 3│       │4 EN
         └───────┘
PinNameDescription
1SWPower switch node. Connected to inductor and Schottky diode
2GNDPower ground
3FBFeedback pin. Connected to output resistor divider (Reference = 0.6V)
4ENEnable pin. High = Active, Low = Shutdown (<1µA current draw)
5INPower supply input pin (2.0V to 24V)
6NCNot connected

Module Terminals

TerminalFunctionDescription
VIN+Positive InputConnect positive voltage supply (e.g. 3.7V LiPo or 5V USB)
VIN-Negative InputConnect ground (GND)
VOUT+Positive OutputStepped-up DC output voltage
VOUT-Negative OutputCommon ground

Specifications

ParameterSymbolMinTypMaxUnitConditions
Input VoltageVINV_{IN}2.0—24.0VDC input
Output Voltage RangeVOUTV_{OUT}VINV_{IN}—28.0VAdjustable via FB resistor network
Feedback VoltageVFBV_{FB}0.5880.6000.612VVIN=5VV_{IN} = 5\text{V}
Switch Current LimitISW_LIMI_{SW\_LIM}—2.0—APeak inductor current limit
Switching FrequencyfSWf_{SW}1.01.21.4MHzOperating frequency
Shutdown CurrentISDI_{SD}—0.11.0µAVEN=0VV_{EN} = 0\text{V}
Efficiencyη\eta909397%VIN=5V,VOUT=12V,IOUT=0.2AV_{IN}=5\text{V}, V_{OUT}=12\text{V}, I_{OUT}=0.2\text{A}

Basic Circuit Diagram (Standalone IC)

text
        Inductor L1 (2.2µH - 10µH)
  VIN ────┬───────███████───────┬───────►|─────┬─────────── VOUT
          │                     │     Schottky │
       [C_IN 22µF]         [Pin 1: SW]  Diode [C_OUT 22µF]
          │                     │              │
         GND               MT3608 IC          R1
                                │              │
                           [Pin 3: FB] ────────┴────[R2]─── GND

Formula for Output Voltage:VOUT=0.6V×(1+R1R2)\text{Formula for Output Voltage:} \quad V_{OUT} = 0.6\text{V} \times \left(1 + \frac{R_1}{R_2}\right)

Wiring (Breakout Module)

MT3608 Module→Source / LoadNotes
VIN+3.7V LiPo / 5V USB PowerInput DC source
VIN-GNDInput Ground
VOUT+12V / 24V DC LoadStepped-up output
VOUT-GNDOutput Ground

Common mistakes

  • Potentiometer requires multiple turns out of the box: Fresh MT3608 modules often arrive with the multi-turn potentiometer set to its maximum resistance. When first powered, VOUTV_{OUT} will appear identical to VINV_{IN}. Rotate the potentiometer brass screw 10 to 20 full counter-clockwise turns until the output voltage begins to rise.
  • Attempting to step DOWN voltage: MT3608 is strictly a boost converter. VOUTV_{OUT} cannot be set lower than VINV_{IN}. If VINV_{IN} rises above the set VOUTV_{OUT}, current flows straight through the inductor and Schottky diode to the output.
  • Exceeding 2A peak switch current: The 2A limit applies to peak current through the internal MOSFET switch, not continuous output load current. Since PIN≈POUTP_{IN} \approx P_{OUT}, output current is limited by: IOUT(max)≈IIN(max)×VINVOUT×EfficiencyI_{OUT(max)} \approx I_{IN(max)} \times \frac{V_{IN}}{V_{OUT}} \times \text{Efficiency} For example, boosting 3.7V to 12V yields a maximum output current of around 500 mA500\text{ mA}.

Notes

  • MT3608 vs LM2596 / XL6009: MT3608 operates at 1.2MHz (far higher than LM2596's 150kHz or XL6009's 400kHz), making it much smaller and ideal for battery-powered projects.

Assets & downloads