MP2225 (IAFRJ / AFRJ) - step-down DC-DC converter with efficiency up to 98%


MP2225 (IAFRJ-AFRJ) - step-down DC-DC converter with efficiency up to 98%The MP2225 (MP2225GJ, IAFRJ mark) is a high frequency synchronous buck DC-DC converter with built-in power MOSFETs. A very compact solution to achieve an output current of up to 5 A with excellent output voltage regulation and minimal ripple over a wide input voltage range.

The MP2225 has a synchronous operation mode. The synchronous topology provides higher efficiency (up to 98%) and allows for more compact designs due to the built-in efficient MOSFET.

In recent years, analog IC vendors have started to produce synchronous DC / DC converters to reduce the power loss that occurs in asynchronous circuits with their external Schottky diodes. The synchronous converter now contains a low-side power MOSFET, replacing the external high-loss Schottky diode. The power dissipated by this MOSFET depends on the on-channel resistance R (ON), while the power loss across the Schottky diode is determined by its forward voltage V (D).

The MP2225 has over-current protection and shuts down when overheated, and there is no over-polarity protection.

MP2225 Converter Specifications

  • Conversion efficiency (COP) : up to 97% (black module) and up to 98% (white module);
  • Switching frequency : 500 kHz;
  • Input voltage : 4.5 to 16 V (max. 18 V);
  • Output voltage : from 0.6 V (adjustable);
  • Output constant current : 5A;
  • Protection : short circuit, overheating;
  • Soft start time : 2.4 ms;
  • Accuracy : 1% at room temperature;
  • Power saving mode : yes;
  • Case : 8-pin TSOT23;
  • Reverse polarity protection : no;

Functional block diagram of MP2225

Functional block diagram of MP2225

Wiring diagram for MP2225 DC-DC module

The MP2225 (MP2225GJ) requires a minimum of readily available standard external components.

Wiring diagram for MP2225 (IAFRJ-AFRJ) DC-DC moduleEN-contact is used to turn the module on and off by supplying logic "1" and "0", respectively. A pull-up resistor is used to keep it always on.

Output voltage adjustment

Two voltages can be removed from the white module - 5.2 V (to compensate for the voltage drop across the wires at high current when charging a mobile phone or other electronic devices) and 3.3 V. By default, the module outputs 5 V, but removing the jumper with a soldering iron (see below) you can get 3.3V.

MP2225 (IAFRJ-AFRJ) - Jumper for 3.3V

If you want to get an output voltage from 1.0 to 5 V, you can change the divider resistors R1 and R2, as shown in the table below:

Vout (V)R1 (kΩ)R2 (kΩ)
1.35one hundred80.6

You can also get any output voltage, for this there is an FB contact on the board to which an external resistor is connected (for more details, see the documentation on page 14).

Connecting the MP2225 module

The white module has three main contacts: supply voltage up to 16 V DC is supplied to the VIN connector (“+” from the power supply), the consumer / load is connected to VOUT (“+”) and GND is the common contact (see below).

Wiring diagram for MP2225 module (white)On some modules there is an additional sticker, VIN and VOUT are swapped on it , because confused when designing (see below). If it becomes necessary to remove the sticker, then keep this in mind, because this module has no protection against reversal.

MP2225 stickerThe situation with the black dala module is a little different, it has 4 classic contacts. Supply voltage up to 16 V DC is supplied to the module contacts IN +, IN- (plus and minus, respectively), and the load is connected to the OUT + and OUT- contacts (see below).

Wiring diagram for MP2225 module (black)

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