The LM25116 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 using an emulated current ramp. Current mode control provides inherent line feedforward, 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 LM25116 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 20-pin HTSSOP package featuring an exposed die attach pad to aid thermal dissipation.
● Emulated Peak Current Mode
● Wide Operating Range (Up to 42 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 36 V
● Precision 1.5% Voltage Reference
● Programmable Current Limit
● Programmable Soft Start
● Programmable Line Undervoltage Lockout
● Automatic Switch to External Bias Supply
● 20-Pin HTSSOP Exposed Pad
● Thermal Shutdown
