LTC announces dual 13-A or single 26-A DC-DC step-down regulator

Date
09/10/2012

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μModule with integral heat sink current shares to 100 A

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The LTM4620 DC-DC μModule step-down regulator with integrated heat sink sources up to 26 A

Linear Technology has announced the LTM4620, a dual 13-A or single 26-A DC-DC step-down regulator that delivers up to 100 A when four devices current share. The LTM4620 is a complete DC-DC ?Module regulator in a 15 x 15 x 4.41 mm LGA package, including inductors, power stages, and control circuits. For optimum heat dissipation, a patented top side heat sink removes heat quickly and evenly. With 200 LFM airflow, 12 VIN to 1.0 VOUT and at full load of 26 A (13 A per output), the LTM4620 internal temperature rises only 60 °C above ambient. With the addition of an external heat sink to the top of the package and 200 LFM airflow, the temperature rise is only 40 °C. The LTM4620 is designed to convert 5 to 12 V inputs to high power, low voltage point-of-load system rails such as 2.5 V to as low as 0.6 V. An accurate reference and an internal remote-sense amplifier guarantee 1.5% accurate output regulation over line, load, and temperature. Sensing the voltage at the load compensates for voltage drops caused by PCB trace impedance. Excellent heat dissipation, low temperature rise, scalable and high output power capability, small footprint, and the low profile package of the LTM4620 enable system designers to lay out more densely populated boards. Applications include mezzanine boards such as ATCA and microTCA systems; point-of-load regulation for advanced processors, ASICs, and recently introduced 28 nm FPGAs; and high-speed SERDES. The LTM4620 features fast short-circuit protection where a current foldback technique reduces IOUT to a minimum, preventing the μModule regulator from overheating while protecting the load as well as the upstream power supply. Once the short-circuit condition is removed, the LTM4620 resumes operation. The LTM4620's two outputs operate at 180 ° out of phase to minimize output ripple (when outputs share current) and input ripple, resulting in the use of fewer and smaller capacitors. For a 100-A design, four LTM4620 devices accurately current share and operate at 90 ° out of phase. Linear Technology rates the LTM4620 for operation from -40 to 125 °C. 1,000-piece pricing starts at $29.99 each. Summary of features

  • Dual 13-A or single 26-A output
  • Multiphase current sharing with multiple LTM4620s up to 100 A
  • Wide input-voltage range: 4.5 to 16 V
  • Output-voltage range: 0.6 to 2.5 V
  • 1.5% maximum total DC-output error
  • Differential remote-sense amplifier
  • Current-mode control / fast transient response
  • Over-current foldback protection & output over-voltage protection
  • Adjustable, synchronizable switching frequency
  • Internal temperature-sensing diode output
  • Low profile (15 x 15 x 4.41) LGA package
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