JAJSPY6 December 2023 LMR66410 , LMR66420 , LMR66430
PRODUCTION DATA
If other voltages are desired, VOUT / FB can be connected to a feedback resistor divider network to set the output voltage. The divider network is comprised of RFBT and RFBB, and closes the loop between the output voltage and the converter. The converter regulates the output voltage by holding the voltage on the VOUT / FB pin equal to the internal reference voltage, VREF. The converter determines whether fixed output voltage or adjustable output voltage is required by sensing the resistance of the feedback path during start-up. To make sure that the converter regulates to the desired output voltage, the typical minimum value for the parallel combination of RFBT and RFBB is 5 kΩ while the typical maximum value is 10 kΩ as shown in Equation 5. Use Equation 6 as a starting point to determine the value of RFBT. Reference Table 8-8 for a list of acceptable resistor values for various output voltages.
VOUT (V) | RFBT (kΩ)(1) | RFBB (kΩ) |
---|---|---|
2.5 | 24.9 | 16.5 |
3.3 | 33.2 | 14.3 |
5 | 49.9 | 12.4 |
6 | 60.4 | 12.1 |
9 | 90.9 | 11.3 |
For this 5-V example, the user can choose the LMR66430R5RXBR and connect VOUT / FB directly to the output capacitor.