MP2225 Module High Efficiency Synchronous Step-Down Converter

Table of Contents

MP2225 module High Efficiency Synchronous Step-Down Converter. The MP2225 is a compact, high-frequency, synchronous step-down converter with built-in power MOSFETs. It can deliver a 5A output current with excellent load and line regulation across a wide input supply range. Operating in synchronous mode for increased efficiency, it also features current-mode operation for fast transient response and easy loop stabilization. The device includes over-current protection and thermal shut down for full protection. With minimal external components required, the MP2225 is available in a space-saving 8-pin TSOT23 package.

Schematic MP2225 module High Efficiency Synchronous Step-Down Converter

Features & Benefits MP2225 module

Wide 4.5V-to-18V Operating Input Range
Adjustable Output Voltage as low as 0.6V
Low 47mΩ/18mΩ RDS(ON) of Internal Power MOSFETs
High Efficiency up to 97%
Fixed 500kHz Switching Frequency
Synchronizes from a 200kHz-to-2MHz External Clock
2.4ms Internal Soft-Start Time
1% Reference Accuracy at Room Temperature
Internal Power-save Mode
OCP with hiccup mode
Available in 8-pin TSOT23

Pin functions
Pin#	Name	Description
1	AGND	Analog Ground. Connect it to GND.
2	IN	Supply Voltage. The MP2225 operates from a 4.5V-to-18V input rail. Requires C1 to decouple the input rail. Connect using a wide PCB trace.
3	SW	Switch Output. Connect using a wide PCB trace.
4	GND	Power Ground. Requires special consideration during PCB layout. Connect to GND with copper traces and vias.
5	BST	Bootstrap. Requires a capacitor between SW and BST pins to form a floating supply across the high-side switch driver.
6	EN/SYNC	EN high to enable the MP2225. Can apply an externai clock to the EN pin to change the switching frequency.
7	VCC	Bias Supply. Decouple with a 0.1μF-to-0.22μF capacitor.
8	FB	Feedback. Connect to the tap of an externai resistor divider from the output to GND to set the output voltage. The frequency fold-back comparator lowers the oscillator frequency when the FB voltage is below 480mV to prevent current-limit run-away during a short-circuit fault condition.

Setting the Output Voltage
The external resistor divider sets the output voltage.
The feedback resistor R1 also sets the feedback loop bandwidth with the internal compensation capacitor. First, choose a value for R1, R2 is then given by:

Mp2225 Module Step-Down Converter Feedback Network

The feedback network—as shown in figure — is highly recommended.

Vout (V)	R1 (kΩ)	R2 (kΩ)
1.0	120	180
1.2	120	120
1.35	100	80.6
1.5	80.6	53.6
1.8	80.6	40.2
2.5	80.6	25.5
3.3	40.2	8.87
5	40.2	5.49

The recommended parameters are based on 500kHz switching frequency, different output inductors and capacitors affect the recommended values of R1 and R2.

BOM MP2225 module High Efficiency Synchronous Step-Down Converter

Parts	Value	Description	Quantity
Capacitors
22uf	C1	C1206 – SMD capacitor	1
0.1uf	C3, C4, C5	C0603 – SMD capacitor	3
22uf	C6, C7	C0805 – SMD capacitor	2
33pf	C9	C0603 – SMD capacitor	1
Resistors
100K (104)	R1	R0603 – SMD resistor	1
10R (10R)	R2	R0603 – SMD resistor	1
40.2K (4022)	R4	R0603 – SMD resistor	1
5.49K (5491)	R5	R0603 – SMD resistor	1
Semiconductors
SMAJ12A	D1	SMA 12V ESD and Surge Protection	1
MP2225GJ	U2	Step-down type Adjustable 4.5V~18V 5A 600mV~17V TSOT-23-8 DC-DC Converter	1
Miscellaneous
4.7uH	L1	2A 22uH Integrated molded inductor ±20% 3.5A SMD,6.6×7.3mm Power Inductor	1