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Wide-Input, High-Frequency, Triple-Output Supplies with Voltage Monitor and Power-On Reset

Complete Triple-Output xDSL Power Supplies for Modems, Routers, and Gateways Save Cost and Reduce Noise

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • Low-Cost DC-DC Controller with Two LDOs
  • Wide Input Range: 4.5V to 28V
  • 300kHz to 1.4MHz Adjustable Switching Frequency
  • Low Noise for High Data-Rate xDSL Applications
  • Synchronizable to External Clock
  • Adjustable Soft-Start
  • Lossless Adjustable Foldback Current Limit
  • Power-On Reset with 140ms Delay
  • Adjustable Input Power-Fail Warning for Dying Gasp
  • Selectable Output-Voltage Sequencing or Output-Voltage Tracking

Applications/Uses

  • Set-Top Boxes
  • Wireless Routers
  • xDSL, Cable, ISDN Modems, and Routers

Description

The MAX8513/MAX8514 integrate a voltage-mode PWM step-down DC-DC controller and two LDO controllers, a voltage monitor, and a power-on reset for the lowest-cost power-supply and monitoring solution for xDSL modems, routers, gateways, and set-top boxes.

The DC-DC controller switching frequency can be set with an external resistor from 300kHz to 1.4MHz, to allow for the optimization of cost, size, and efficiency. For noisesensitive applications, the DC-DC controller can also be synchronized to an external clock, minimizing noise interference. Operation above 1.1MHz reduces noise for high data-rate xDSL applications. An adjustable soft-start and adjustable foldback current limit provide reliable startup and fault protection. The DC-DC controller output voltage can be set externally to a voltage from 1.25V to 5.5V. Current limiting is accomplished by inductor current sensing for improved efficiency, or by an external sense resistor for better accuracy.

The MAX8513/MAX8514s' first LDO controller is designed to provide a low-cost, high-current regulated output from 0.8V to 5.5V using an N-channel MOSFET or a low-current output using a low-cost NPN transistor. The MAX8513's second regulator can be used to generate 0.8V to 27V output with a low-cost PNP transistor. Both LDO regulators can operate either from the DC-DC controller output or from a higher voltage derived with a flyback overwinding on the DC-DC converter inductor. The MAX8514's second LDO regulator is designed to provide a negative output with an NPN transistor.

A sequence input allows the outputs to either power up together, or for the DC-DC regulator to power up first and each LDO controller to power up in sequence. An input power-fail output (active-low PFO) is provided for input power-fail warning, such as in dying-gasp applications. A power-on reset circuit with a 140ms delay is also included to indicate when all outputs have achieved regulation and stabilized.

Simplified Block Diagram

MAX8513, MAX8514: Pin Configuration MAX8513, MAX8514: Pin Configuration Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .