LTC7149, 60 V, 4 A Synchronous Buck for Inverting

By Analog Devices Inc 32

LTC7149, 60 V, 4 A Synchronous Buck for Inverting

Linear Technology's LTC7149 is a high-efficiency, 60 V, 4 A synchronous monolithic step-down regulator for inverting output applications. The regulator features a single resistor programmable output voltage and high efficiency over a wide VOUT range.

The inverting regulator operates from an input voltage range of 3.4 V to 60 V and provides an adjustable output from -28 V to 0 V while delivering up to 4 A of inductor current. The switching frequency is also set with an external resistor. A user-selectable mode input is provided to allow the user to trade-off ripple noise for efficiency at light loads; burst mode operation provides the highest efficiency at light loads, while forced continuous mode provides low output ripple. The MODE / SYNC pin can also be used to synchronize the switching frequency to an external clock. Internal level-shift circuits allow the I/O pins (RUN, MODE / SYNC, and PGOOD) to be referenced to board GND.

Design Note: Inverting Regulator Takes Inputs Up to 50 V and Supports Outputs to 4 A

Features
  • Wide VIN range: 3.4 V to 60 V
  • Wide VOUT range: -28 V to 0 V
  • Single resistor VOUT programming
  • Integrated 110 mΩ top N-channel / 50 mΩ bottom N-channel MOSFETs
  • Regulated IQ: 440 μA, shutdown IQ: 15 μA
  • Board GND referenced I/O pins (RUN, PGOOD, and MODE / SYNC)
  • Accurate resistor programmable frequency 300 kHz to 3 MHz with ±50% frequency sync range
  • 92% efficiency with 12 VIN and -5 VOUT
  • ±0.8% output voltage accuracy
  • Peak-current mode operation
  • Burst Mode® operation, forced continuous mode
  • Programmable soft-start
  • Over-temperature protection
  • Available in 28-lead (4 mm x 5 mm) QFN and TSSOP packages
     
Applications
  • Industrial
  • Telecom power supplies
  • Distributed power systems

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