SLVSK53 October 2025 TPS7E82
ADVANCE INFORMATION
For this design example, VOUT is set to 3.3V. The following equations set the feedback divider resistors for the desired output voltage:
For improved output accuracy, use Equation 16 and IFB = 10nA as listed in the Section 5.5 table to calculate the upper limit for series feedback resistance (R1 + R2 ≤ 3.3MΩ).
The control-loop error amplifier drives the FB pin to the same voltage as the internal reference (VFB = 1.2V, as listed in the Section 5.5 table). Use Equation 15 to determine the ratio of R1 / R2 = 1.75 Use this ratio and solve Equation 16 for R1. Now calculate the upper limit for R1 ≤ 2.1MΩ. Select a standard value resistor for R1 = 1.75MΩ.
Reference Equation 17 and solve for R2:
From Equation 17, R2 = 1MΩ is determined. Select a standard value resistor for R2 = 1MΩ. Verify that the feedback divider current is greater than the minimum value in the Section 5.3 table.
The following equation calculates the feedback divider current.