JAJSL65 February 2023 LM5148-Q1
PRODUCTION DATA
The LM5148-Q1 output can be independently configured for one of three fixed output voltages without external feedback resistors, or adjusted to a desired voltage using an external resistor divider. Set the output to 3.3 V by connecting FB directly to VDDA. Alternatively, set the output to either 5 V or 12 V by installing a 24.9-kΩ or 49.9-kΩ resistor between FB and VDDA, respectively. See Table 8-1.
PULLUP RESISTOR TO VDDA | VOUT SETPOINT |
---|---|
0 Ω | 3.3 V |
24.9 kΩ | 5 V |
49.9 kΩ | 12 V |
Not installed | External FB divider setting |
The configuration settings are latched and cannot be changed until the LM5148-Q1 is powered down (with the VCC voltage decreasing below its falling UVLO threshold) and then powered up again (VCC rises above 3.4-V typical). Alternatively, set the output voltage with an external resistor divider from the output to AGND. The output voltage adjustment range is between 0.8 V and 55 V. The regulation voltage at FB is 0.8 V (VREF). Use Equation 6 to calculate the upper and lower feedback resistors, designated as RFB1 and RFB2, respectively.
The recommended starting value for RFB2 is between 10 kΩ and 20 kΩ.
If low-IQ operation is required, take care when selecting the external feedback resistors. The current consumption of the external divider adds to the LM5148-Q1 sleep current (9.5 µA typical). The divider current reflected to VIN is scaled by the ratio of VOUT / VIN.