For those who make analog circuits, a stable and efficient power module is essential. This time I bring you a wide voltage DCDC module.

Components

The core of this module is the SY8303 chip.

Main features of the chip

The chip input voltage range is 4.5V-40V, and the wide voltage is suitable for various working environments. The output current can reach 3A, which can meet most situations of analog circuit construction.

Reference circuit

The peripheral circuit is very simple. It only requires an inductor and some resistors and capacitors. Analyze the component selection according to the data sheet.

Resistor part

R1 and R2 are used to adjust the output voltage, the formula is: R2=(0.6/Vout-0.6)*R1. For example, the circuit can use a combination of 110k and 15k to output a 5V voltage: a combination of 68K and 15K can be used to output a 3.3V voltage:

Inductance part

The selected value of the inductor must be realistic. If the inductance value is too small, the input energy exceeds the storage capacity of the inductor, which will cause inductor saturation; if the inductance value is too large, the input energy only accounts for a small part of its capacity, causing waste. Here I choose a 4.7uf inductor. When selecting an inductor, you should also pay attention to the DCR of the inductor not being too large. The data sheet recommends that it be less than 50mΩ: I chose the inductor number C385253, and its DCR is 37mΩ, which meets the requirements.

Capacitor part

The most important capacitor is the filter capacitor at the input and output ends. I chose two 10uf capacitors in parallel and added a 100nF small capacitor to filter out high frequencies to obtain pure power.

PCB layout

We can refer to the layout reference diagram given in the data sheet: the key points are as follows: 1. The inductor should be as close to the chip as possible, and the length of the LX line should be minimized. 2. Do not route wires under the inductor, especially high-frequency signal lines. Keep the wires as far away from the inductor area as possible, if necessary. You can hollow out the copper area for this part to reduce unnecessary energy loss: 3. The capacitors at the input and output ends should be as close to the chip as possible:

physical part

When the input voltage is 12V: measure the 3.3V terminal voltage: measure the 5V terminal voltage: you can see that the output terminal voltage is relatively accurate.