JAJSV63A August 2024 – August 2024 LM5137-Q1
ADVANCE INFORMATION
The LM5137-Q1 has a precision enable circuit on each EN input. When the EN1 or EN2 voltage is greater than 1V, switching is enabled on the respective channel. If the EN1 and EN2 pins are pulled below 0.5V, the LM5137-Q1 is in shutdown with an IQ of 4μA (typical) current consumption from VIN. When the EN1 or EN2 voltage is between 0.5V and 1V, the LM5137-Q1 is in standby mode with the VCC regulator active but the controller is not switching. The non-switching input quiescent current in standby mode is 130μA typical.
The LM5137-Q1 is enabled with a voltage greater than 1V. However, many applications benefit from using a resistor divider RUV1 and RUV2, as shown in Figure 7-2, to establish a precision UVLO level. Add RUV3 in series to provide additional voltage hystersis. Avoid leaving the EN1 and EN2 pins floating. Keep the EN1/2 voltage under 80V.
Use Equation 1 to calculate the UVLO resistors, where VIN(on) and VIN(off) are the required input voltage turn-on and turn-off thresholds.