ZHCSE17B July 2015 – November 2017 LM43601-Q1
PRODUCTION DATA.
The undervoltage lockout (UVLO) is adjusted using the external voltage divider network of RENT and RENB. RENT is connected between VIN and the EN pins of the LM43601-Q1 device. RENB is connected between the EN pin and the GND pin. The UVLO has two thresholds, one for power up when the input voltage is rising and one for powerdown or brownouts when the input voltage is falling. Equation 24 can be used to determine the VIN (UVLO) level.
The EN rising threshold for LM43601-Q1 is set to be 2.1 V. Choose the value of RENB to be 1 MΩ to minimize input current going into the converter. If the desired VIN (UVLO) level is at 5 V, then the value of RENT can be calculated using Equation 25:
The above equation yields a value of 1.37 MΩ. The resulting falling UVLO threshold can be calculated as follows: