• Emulated Peak Current Mode
• Wide Operating Range Up to 100 V
• Low IQ Shutdown (< 10 µA)
• Drives Standard or Logic Level MOSFETs
• Robust 3.5-A Peak Gate Drive
• Free-run or Synchronous Operation to 1 MHz
• Optional Diode Emulation Mode
• Programmable Output from 1.215 V to 80 V
• Precision 1.5% Voltage Reference
• Programmable Current Limit
• Programmable Soft-Start
• Programmable Line Undervoltage Lockout
• Automatic Switch to External Bias Supply
• HTSSOP-20 Exposed Pad
• Thermal Shutdown

• Automotive Infotainment
• Industrial DC-DC Motor Drivers
• Automotive USB Adapters
• Telecom Servers

The LM5116 is a 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 operating frequency is programmable from 50 kHz to 1 MHz. The LM5116 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 low quiescent current shutdown disables the controller and consumes less than 10 µA of total input current.

Additional features include a high-voltage bias regulator, automatic switch-over to external bias for improved efficiency, thermal shutdown, frequency synchronization, cycle-by-cycle current limit, and adjustable line undervoltage lockout. The device is available in a power enhanced HTSSOP-20 package featuring an exposed die attach pad to aid thermal dissipation.