PT7778A datasheet by Texas Instruments

PT7778A Frequently Asked Questions (FAQs)

• What is the recommended input capacitor value for the PT7778A?
  The recommended input capacitor value is 10uF to 22uF, with a voltage rating of at least 25V. This ensures stable operation and reduces noise.
• How do I optimize the layout for the PT7778A to minimize EMI?
  To minimize EMI, keep the input and output capacitors close to the IC, use a solid ground plane, and keep the switching node (SW pin) away from sensitive analog circuits. Also, use a shielded inductor and orient it to minimize radiation.
• What is the maximum ambient temperature for the PT7778A?
  The maximum ambient temperature for the PT7778A is 85°C. However, the device can operate up to 125°C junction temperature, but with derated performance.
• Can I use the PT7778A in a synchronous rectification configuration?
  Yes, the PT7778A can be used in a synchronous rectification configuration. However, it requires an external FET driver and a Schottky diode for the synchronous rectifier. TI provides an application note (SLUA271) that details the design considerations and implementation.
• How do I adjust the output voltage of the PT7778A?
  The output voltage of the PT7778A can be adjusted by changing the resistive divider ratio (R1 and R2) connected to the FB pin. The output voltage is calculated using the formula: Vout = 0.8V x (1 + R2/R1).