The LM25119 is a dual synchronous buck controller intended for step-down regulator applications from a high voltage or widely varying input supply. The control method is based upon current mode control utilizing an emulated current ramp. Current mode control provides inherent line feed-forward, cycle-by- cycle current limiting and ease of loop compensation. The use of an emulated control ramp reduces noise sensitivity of the pulse-width modulation circuit, allowing reliable control of very small duty cycles necessary in high input voltage applications. The switching frequency is programmable from 50 kHz to 750 kHz. The LM25119 drives external high-side and low-side NMOS power switches with adaptive dead- time control. A user-selectable diode emulation mode enables discontinuous mode operation for improved efficiency at light load conditions. A high voltage bias regulator with automatic switch-over to external bias further improves efficiency. Additional features include thermal shutdown, frequency synchronization, cycle-by-cycle and hiccup mode current limit and adjustable line under-voltage lockout. The device is available in a power enhanced leadless WQFN-32 package featuring an exposed die attach pad to aid thermal dissipation.

• LM25119Q is an Automotive Grade product that is AEC-Q100 grade 1 qualified (–40°C to 125°C operating junction temperature).
• Emulated peak current mode control
• Wide operating range from 4.5 V to 42 V
• Easily configurable for dual outputs or interleaved single output
• Robust 3.3 A peak gate drive
• Switching frequency programmable to 750 kHz
• Optional diode emulation mode
• Programmable output from 0.8 V
• Precision 1.5% voltage reference
• Programmable current limit
• Hiccup mode overload protection
• Programmable soft-start
• Programmable line under-voltage lockout
• Automatic switch-over to external bias supply
• Channel2 enable logic input
• Leadless WQFN-32 (5 mm × 5 mm) package