• Input Voltage Range: 2.7V to 20V

• 38V Open LED Protection

• 200mV Reference Voltage

• 500kΩ Pull-Down Resistor on CTRL Pin

• PWM Brightness Control

• 5kHz to 100kHz PWM Dimming Frequency Range

• Soft-Start Function

• Up to 90% Efficiency

• -40℃ to +85℃ Operating Temperature Range

• Available in Green TDFN-2×2-6L and TSOT-23-6 Packages

With a 40V rated integrated switch FET, the SGM3733B is a boost converter that drives LEDs in series. The boost converter runs at 650kHz fixed switching frequency to reduce output ripple, improve conversion efficiency, and allows for the use of small external components. 

The default white LED current is set with the external sensor resistor RSET, and the feedback voltage is regulated to 200mV, as shown in the typical application. During the operation, the LED current can be controlled using PWM signal through the CTRL pin. The duty cycle of pulse width modulation (PWM) signal determines the feedback reference voltage. In PWM mode, the SGM3733B does not burst the LED current; therefore, it does not generate audible noises on the output capacitor. For maximum protection, the device features integrated open LED protection that disables the SGM3733B to prevent the output voltage from exceeding the IC’s absolute maximum voltage ratings during open LED conditions.