ZHCSN38D October 2021 – April 2024 LMR54406 , LMR54410
PRODUCTION DATA
The system undervoltage lockout (UVLO) is adjusted using the external voltage divider network of RENT and RENB. The UVLO has two thresholds, one for power up when the input voltage is rising and one for power down or brown outs when the input voltage is falling. Equation 13 can be used to determine the VIN UVLO level.
The EN rising threshold (VENH) for LMR54410 is set to be 1.23 V (typical). Choose a value of 200 kΩ for RENB to minimize input current from the supply. If the desired VIN UVLO level is at 6.0 V, then the value of RENT can be calculated using Equation 14:
The above equation yields a value of 775.6 kΩ, a standard value of 768 kΩ is selected. The resulting falling UVLO threshold, equal to 5.3 V, can be calculated by Equation 15 where EN hysteresis voltage, VEN_HYS, is 0.13 V (typical).