LTC3872ETS8#PBF - Analog Devices

LTC3872ETS8#PBF Frequently Asked Questions (FAQs)

• What is the recommended PCB layout for optimal performance of the LTC3872?
  A good PCB layout for the LTC3872 involves keeping the high-frequency switching nodes (e.g., SW, VIN, and VOUT) away from sensitive analog nodes, using a solid ground plane, and minimizing trace lengths and widths to reduce parasitic inductance and capacitance. A 4-layer board with a dedicated power plane and a solid ground plane is recommended.
• How do I select the right inductor for my LTC3872 design?
  When selecting an inductor for the LTC3872, consider the inductor's saturation current, DC resistance, and core material. A good starting point is to choose an inductor with a saturation current rating of at least 1.5 times the maximum output current, and a DC resistance of less than 100 mΩ. Ferrite or iron powder cores are suitable for most applications.
• What is the maximum ambient temperature range for the LTC3872?
  The LTC3872 is rated for operation from -40°C to 125°C, but the maximum ambient temperature range depends on the specific application and the device's power dissipation. For most applications, the maximum ambient temperature is around 85°C to 90°C, but this can be derated based on the device's power dissipation and the thermal resistance of the package.
• How do I configure the LTC3872 for a specific output voltage?
  The LTC3872 output voltage is set using the FB pin and a resistive divider network. The FB pin is connected to the output voltage through a resistive divider, and the ratio of the resistors determines the output voltage. The datasheet provides a formula to calculate the required resistor values for a given output voltage.
• What is the purpose of the SYNC/MODE pin on the LTC3872?
  The SYNC/MODE pin on the LTC3872 allows the user to synchronize the switching frequency with an external clock signal, or to select between forced continuous conduction mode (FCCM) and pulse-skipping mode (PSM). In FCCM, the converter operates at a fixed frequency, while in PSM, the converter skips pulses to reduce power consumption at light loads.