VIPER222LSTR datasheet by STMicroelectronics

VIPER222LSTR Frequently Asked Questions (FAQs)

• What is the recommended PCB layout for optimal performance of VIPER222LSTR?
  A good PCB layout for VIPER222LSTR involves keeping the high-frequency switching nodes (e.g., drain-source voltage) as small as possible, using a solid ground plane, and placing the input and output capacitors close to the IC. A 4-layer PCB with a dedicated power plane and a solid ground plane is recommended.
• How do I ensure reliable start-up of VIPER222LSTR in my design?
  To ensure reliable start-up, ensure that the input voltage rises slowly (e.g., using a soft-start circuit) and that the input capacitor is properly sized to handle the inrush current. Also, make sure the output voltage is properly regulated before enabling the load.
• What is the maximum allowed temperature range for VIPER222LSTR?
  The VIPER222LSTR is rated for operation from -40°C to 150°C (junction temperature). However, the maximum allowed ambient temperature range depends on the specific application and cooling conditions. Typically, the ambient temperature range is -40°C to 85°C.
• How do I choose the right input and output capacitors for VIPER222LSTR?
  Choose input capacitors with low ESR (Equivalent Series Resistance) and high ripple current capability. For output capacitors, choose ones with low ESR and high capacitance to ensure good output voltage regulation. The datasheet provides guidelines for capacitor selection.
• What are the key considerations for EMI filtering in VIPER222LSTR-based designs?
  To minimize EMI, use a common-mode choke and a differential-mode filter at the input, and ensure good PCB layout practices (e.g., keep high-frequency nodes small, use a solid ground plane). Additionally, consider using shielding and filtering components (e.g., ferrite beads) to reduce radiated emissions.