MT3608 boost converter: specs and pinout
A step-up (boost) DC-DC converter built on the MT3608 chip: it raises a lower DC voltage to a higher one, with the output set by a resistor divider on the chip's feedback pin. This page covers the MT3608 chip; the module board is not covered by an official document.
Specs
| Spec | Value | Source |
|---|---|---|
| Input voltage | 2 V to 24 V (operating); IN and EN pins absolute maximum -0.3 V to 26 V | source Features (p.1); Absolute Maximum Ratings (p.2); Electrical Characteristics (p.3) |
| Output voltage | Adjustable, up to 28 V | source Features (p.1) |
| Feedback reference | 0.6 V typ (0.588-0.612 V); Vout = 0.6 V x (1 + R1/R2) | source Electrical Characteristics (p.3); Application Information (p.6) |
| Switch current limit | 4 A min (VIN 5 V, 50% duty) | source Electrical Characteristics (p.3) |
| Switching frequency | 1.2 MHz fixed | source Features (p.1) |
| Maximum duty cycle | 90% min (VFB = 0 V) | source Electrical Characteristics (p.3) |
| Quiescent current | 100 uA typ in PFM (no switching); 1.6 mA typ in PWM; 0.1 uA typ in shutdown | source Electrical Characteristics (p.3) |
| Enable input | EN high (1.5 V min) turns on, low (0.4 V max) turns off; connect EN to IN for automatic start | source Pin Description (p.2); Electrical Characteristics (p.3) |
| Recommended inductor | 4.7 uH to 22 uH | source Application Information (p.6) |
| Operating temperature | -40 C to +85 C | source Absolute Maximum Ratings (p.2) |
| Switch limits and thermal shutdown | Peak SW sink/source current 4 A absolute maximum; SW current limit 4 A min (VIN 5 V, 50% duty); SW on-resistance 80 mohm typ, 150 mohm max; thermal shutdown 155 C; junction temperature 160 C absolute maximum | source Absolute Maximum Ratings (p.2); Electrical Characteristics (p.3) |
Power
| Value | Source | |
|---|---|---|
| Supply | VIN 2 V to 24 V | source Electrical Characteristics (p.3) |
| Current | 1.6 mA typ quiescent in PWM mode (load current not included) | source Electrical Characteristics (p.3) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
Rows are the MT3608 chip's SOT23-6 pins. The module board (terminal labels, inductor and diode values, how the output is trimmed, any input protection) is not covered by an official document, so check the printed labels and set the output with a meter.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| SW | Power switch output (drain of the internal MOSFET); inductor and rectifier connect here | Swings between GND and 28 V | SOT23-6 pin 1 | source Pin Description (p.2) |
| GND | Ground | SOT23-6 pin 2 | source Pin Description (p.2) | |
| FB | Feedback input; the FB voltage is 0.6 V, connect a resistor divider | 0.6 V | SOT23-6 pin 3 | source Pin Description (p.2) |
| EN | Regulator on/off control: high turns on, low turns off | High 1.5 V min, low 0.4 V max | SOT23-6 pin 4; connect to the input supply for automatic start | source Pin Description (p.2); Electrical Characteristics (p.3) |
| IN | Input supply, must be locally bypassed | 2-24 V | SOT23-6 pin 5 | source Pin Description (p.2) |
Build with it
Project ideas for the MT3608 boost converter. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Li-ion powered Uno: One cell (about 3.7 V) is inside the 2-24 V input range; set the output to 5 V with a meter before connecting the Uno. Learning project. Feed the Uno's 5 V pin only with USB unplugged, since that pin bypasses the board's input protection.
- Portable WS2812 light (reduced brightness): The ESP32's 3.3 V data output is below the ring's 0.7 x VDD (3.5 V at 5 V) input-high level, so pass the data line through the stocked 3.3 V to 5 V level converter (3.3 V on the low side, the booster's 5 V on the high side), joining grounds. LED current is not on the WS2812B sheet; a full-white ring can draw over 1 A (about 60 mA per LED at full white is a common estimate, not a sheet figure), so cap brightness in firmware to keep the 5 V load, ring plus ESP32, at about 1 A or less. At 1 A and 5 V out from a 3.7 V cell, the input current is about 1.6 A (derived at about 85% efficiency) and rises as the cell sags; check the cell and holder can supply it, and that the booster's inductor does not saturate or overheat. Use a protected 18650 cell, or run the cell through the stocked TP4056 module with protection, in the stocked single-cell holder; an unprotected bare cell should not feed a booster that can draw about 1.6 A.
- Pico weather node: The boost output set to 5 V feeds the Pico's VSYS through a Schottky diode (1N5819 from the diode pack, anode to the booster) so it cannot back-feed USB; the charger board keeps the cell topped up from USB.
Common mistakes
- Setting the output above 28 V or feeding more than 24 V in: the datasheet gives 28 V maximum output and 2-24 V input (IN and EN absolute maximum 26 V) (source)
- Connecting a load before setting the output: the output follows the feedback divider (Vout = 0.6 V x (1 + R1/R2)), so measure it with a multimeter before connecting a 5 V device (source)
- Assuming 2 A output from the name: the datasheet gives a 4 A switch limit (VIN 5 V, 50% duty) and no output-current rating, and the switch current rises as the input falls, so keep the load well below the name's figure and check the module for heat; thermal shutdown is 155 C (source: link, Electrical Characteristics p.3)
Not covered by the official source
- Module board is not covered by an official document: terminal labels, trim pot, inductor and Schottky diode values and any input protection are unknown.
- The 2 A in the listing name is the headline figure of the chip title; the module's real continuous output current depends on input voltage, boost ratio and the inductor, and is not stated in the datasheet.
- This V1.0 sheet states up to 97% efficiency; another revision is reported to say 93%, so no efficiency figure is quoted.
- Clone chips exist; check the chip marking on your module.
- No continuous output current is quoted; the 2 A in the listing name is not sourced. Input current figures in the ideas are derived estimates: Iin = Vout x Iout / (Vin x efficiency), with efficiency assumed about 85% (the sheet says up to 97% at the peak of its curve).
Sources
- link (Aerosemi MT3608 High Efficiency 1.2MHz 2A Step Up Converter datasheet, MT3608/V1.0)