JAJSL65 February 2023 LM5148-Q1
PRODUCTION DATA
The EN pin can be connected to a voltage as high as 80 V. The LM5148-Q1 has a precision enable. When the EN voltage is greater than 1 V, controller switching is enabled. If the EN pin is pulled below 0.5 V, the LM5148-Q1 is in shutdown with an IQ of 2.3 μA (typical) current consumption from VIN. When the enable voltage is between 0.5 V and 1 V, the LM5148-Q1 is in standby mode with the VCC regulator active but the controller is not switching. In standby mode, the non-switching input quiescent current is 124-μA typical. The LM5148-Q1 is enabled with a voltage greater than 1.0 V. However, many applications benefit from using a resistor divider RUV1 and RUV2, as shown in Figure 8-2, to establish a precision UVLO level. TI does not recommend leaving the EN pin floating.
Use Equation 2 and Equation 3 to calculate the UVLO resistors given the required input turn-on and turn-off voltages.