LM5119 Dual Synchronous Buck Controller


National Semiconductor's 65V dual-channel, dual-phase synchronous
buck controller saves PCB space in high voltage applications


National Semiconductor - LM5119 Dual Synchronous Buck Controller National Semiconductor's LM5119 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 50kHz to 750kHz. The LM5119 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 switchover to external bias further improves efficiency. Additional features include thermal shutdown, frequency synchronization, cycle-by-cycle and hiccup mode current limit, and adjustable line undervoltage lockout. The device is available in a power enhanced leadless LLP-32 package that features an exposed die attach pad to aid thermal dissipation.   LM5119 Datasheet

   Features
  • Emulated peak current mode control
  • Wide operating range from 5.5V to 65V
  • Easily configurable for dual outputs or interleaved single output
  • Robust 3.3A peak gate drive
  • Switching frequency programmable to 750kHz
  • Optional diode emulation mode
  • Programmable output from 0.8V
  • Precision 1.5% voltage reference
  • Programmable current limit
  • Hiccup mode overload protection
  • Programmable soft-start
  • Programmable line undervoltage lockout
  • Automatic switchover to external bias supply
  • Channel2 enable logic input
  • Thermal shutdown
  • Leadless LLP32 (5mm x 5mm) package

IC
Digi-Key Part Number Packaging Voltage - Output Package  
LM5119PSQE/NOPBTR-ND Tape & Reel Adj to 0.8V 32-LLP LM5119 Datasheet
LM5119PSQE/NOPBCT-ND Cut Tape
LM5119PSQE/NOPBDKR-ND Digi-Reel®

Evaluation Board
Digi-Key Part Number Description
LM5119EVAL/NOPB-ND The LM5119EVAL evaluation board provides the design engineer with a fully functional dual output buck converter, employing the LM5119 Dual Emulated Current Mode Synchronous Buck Controller. The evaluation board is designed to provide both 10V and 5V outputs over an input range of 14V to 55V. Also the evaluation board can be easily configured for a single 10V, 8A regulator.