STMicroelectronics synchronous step-down controller is compact and flexible to handle extreme step-down ratios

     STMicroelectronics introduces the L3751 synchronous step-down controller with compact size and input voltage range of 6V to 75V for applications ranging from industrial equipment to pure electric light vehicles. The 3.5mm x 4.5mm controller is also suitable for commonly used 24V and 48V telecom and networking equipment.

     The L3751's minimum on-off time of 40ns and extremely low duty cycle allows for a large step-down ratio, enabling designers to supply power directly to low-voltage devices without the use of an intermediate power converter, which helps simplify application circuit design and reduce bill of Materials (BOM) costs. The device incorporates a 7.5V grid driver power supply.

     In addition to a wide supply voltage range, the L3751 also withstands 100V input voltage and can operate in harsh electrical environments. Switching frequencies can be adjusted in the 100 KHZ to 1MHz range, thus giving designers the flexibility to select external mosFeTs and passive components to optimize circuit size, performance, and cost.

     In order to improve energy efficiency and minimize ripple current, the L3751 adopts diode simulation mode with pulse jumping function under light load. It also provides comprehensive electrical protection for applications, including overheating protection, input undervoltage locking, burp-mode constant current protection, and programmable current detection. The product also has an external enable pin and collector open circuit power good indicator.