Common problems in PCB design

Home | Events | PCB | About Us | News | Contact Us

The packaging of resistors and capacitors depends on the components' specifications. In short, for resistors, the packaging is determined by resistance, capacitance, and power. The larger the power, the larger the package size. For capacitors, the packaging depends on capacitance and withstand voltage. The higher the capacitance and withstand voltage, the larger the package size. It is recommended to refer to the corresponding components for specific details.

When connecting resistors in series between the pin connections of a chip, it is common in signal transmission. The function of the resistor is to prevent crosstalk, improve the transmission success rate, and sometimes prevent inrush current. The resistance value is generally small, less than 100 ohms.

Common problems in PCB design

The coupling capacitor should be placed as close as possible to the power pin. The coupling capacitor serves two functions between the power supply and the ground: it acts as an energy storage capacitor to prevent voltage drop due to sudden changes in current, filtering ripple, and as a bypass for high-frequency noise. The typical decoupling capacitor value in digital circuits is 0.1μF. The typical distributed inductance value for this capacitor is 5μH. The 0.1μF decoupling capacitor has a distributed inductance of 5μH and its parallel resonance frequency is about 7MHz. This means it has a better decoupling effect for noise below 10MHz and has little effect on noise above 40MHz. When 0.1μF and 10μF capacitors are used in parallel, the resonance frequency is above 20MHz, resulting in better removal of high-frequency noise and improved decoupling and bypassing effects. It is advisable to add one coupling capacitor for approximately every 10 ICs, with a value of about 1μF. It is best to avoid using aluminum electrolytic capacitors due to their inductance at high frequencies and instead use tantalum capacitors or polycarbonate capacitors.

The choice of capacitance is closely related to frequency. For example, the capacitor of the crystal oscillator is used to match the crystal and the oscillator circuit to facilitate circuit startup and to have a certain "fine-tuning" effect on the frequency. As for the selection of the rated power of the resistor, it is generally 0.25W or 0.125W.

Why Choose China PCBA Supplier KSPCBA as Your PCB design Manufacturer?

– Experienced and skilled team

– State-of-the-art equipment

– Strict quality control

– Excellent customer service

– Competitive price