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LM34919 PowerWise® Regulator


National Semiconductor's ultra small 40V, 600mA constant on-time buck switching regulator from the PowerWise® family


LM34919 PowerWise® RegulatorNational Semiconductor's LM34919 step down switching regulator features all of the functions needed to implement a low cost, efficient, buck bias regulator capable of supplying 0.6A to the load. This buck regulator contains an N-channel buck switch and is available in a micro SMD package. The constant on-time feedback regulation scheme requires no loop compensation, resulting in a fast load transient response and simplifying circuit implementation.

The operating frequency remains constant with line and load variations due to the inverse relationship between the input voltage and the on time. The valley current limit results in a smooth transition from constant voltage to constant current mode when the current limit is detected, reducing the frequency and output voltage without the use of foldback. Additional features include VCC under-voltage lockout, thermal shutdown, gate drive under-voltage lockout, and maximum duty cycle limiter.

  • Features
  • Applications
  • Diagram
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Features
  • Integrated N-channel buck switch
  • Integrated start-up regulator
  • Input voltage range: 8V to 40V
  • No loop compensation required
  • Ultra-fast transient response
  • Operating frequency remains constant with load current and input voltage
  • Maximum switching frequency: 2.0MHz
  • Maximum duty cycle limited during start-up
  • Adjustable output voltage
  • Valley current limit: 0.64A
  • Precision internal reference
  • Low bias current
  • Highly efficient operation
  • Thermal shutdown

Applications
  • High efficiency point-of-load (POL) regulator
  • Non-isolated telecommunication buck regulator
  • Secondary high voltage post regulator

Diagram

LM34919

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Digi-Key P/N National Semiconductor P/N Datasheet
LM34919BTL/NOPBCT-ND LM34919BTL/NOPB LM34919 PowerWise® Regulator Datasheet
LM34919BQTL/NOPBCT-ND LM34919BQTL/NOPB LM34919 PowerWise® Regulator Datasheet
LM34919TLCT-ND LM34919TL/NOPB LM34919 PowerWise® Regulator Datasheet