SNVAA65 March   2023 LM63610-Q1 , LM63615-Q1 , LM63625-Q1 , LM63635-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1Inverting Buck-Boost Topology
    1. 1.1 Concept
    2. 1.2 Output Current Calculations
    3. 1.3 Voltage Range of Inverting Buck-Boost Configuration
  4. 2Design Considerations
    1. 2.1 Bypass Capacitor and Optional Schottky Diode
  5. 3External Components
    1. 3.1 Capacitor Selection
  6. 4Digital Pin Configurations
    1. 4.1 Optional Enable (EN) Level Shifter
    2. 4.2 Power-Good (PG) Pin
  7. 5Typical Performance
    1. 5.1 VOUT = -3.3 V, 2.1 MHz Typical Performance
    2. 5.2 VOUT = -3.3 V, 400 kHz Typical Performance
    3. 5.3 VOUT = -5 V, 2.1 MHz Typical Performance
    4. 5.4 VOUT = -5 V, 400 kHz Typical Performance
  8. 6Conclusion
  9. 7References

3 External Components

The LM63615-Q1 has integrated power MOSFETs and requires an inductor, input capacitance, and output capacitance. Feedback resistors might or might not need to be used depending on the application. In this application, the output voltage select pin (VSEL) is tied to either VCC or AGND depending on the desired output voltage. If an adjustable output voltage is required, the feedback pin (FB) can be connected with feedback resistors to choose a specific output voltage. The adjustable output can be used to improve the system loop response by placing a feed-forward capacitor, CFF, across the top feedback resistor. Refer to the data sheet for proper sizing of CFF.