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Tracking, Sinking and Sourcing, Synchronous Buck Controller for DDR Memory and Termination Supplies

Reduce Capacitors and Cost of DDR Supplies

Product Details

Key Features

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 28
VOUT1 (V) (min) 0.4
VOUT1 (V) (max) 5
IOUT1 (A) (max) 25
Switch Type External
Output Adjust. Method Dyn. REF In
Resistor
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 550
Package/Pins QSOP/16
Budgetary
Price (See Notes)
4.68
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Simplified Block Diagram

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Parameters

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 28
VOUT1 (V) (min) 0.4
VOUT1 (V) (max) 5
IOUT1 (A) (max) 25
Switch Type External
Output Adjust. Method Dyn. REF In
Resistor
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 550
Package/Pins QSOP/16
Budgetary
Price (See Notes)
4.68

Key Features

  • 25A Sourcing and Sinking Current
  • Automatically Sets VTT to 1/2VDDR
  • VTT and VTTR Within 1% of 1/2VDDR
  • Smallest Output Capacitors
  • 4.5V to 14V (or 28V with Resistor-Divider) Input Voltage Range
  • 1.5V to 3.6V Input DDR Range
  • 200kHz/300kHz/400kHz/550kHz Preset Switching Frequencies
  • Variable Switching Frequency of Up to 1MHz
  • Overcurrent Protection Without Current-Sense Resistor
  • Internal Soft-Start
  • VTTR Reference Sources and Sinks Up to 25mA
  • Quick-PWM Control for Fastest Loop Response
  • Up to 96% Efficiency
  • 16-Pin QSOP Package
  • Applications/Uses

    • AGTL Bus Termination Supplies
    • Cell Phone Base Stations
    • DDR Memory Power Supplies
    • Desktop Computers
    • Networking Systems
    • Notebook Computers
    • Processor or DSP Core Supply
    • Storage

    Description

    The MAX1917 provides a complete power-management solution for DDR memory. It contains a synchronous buck controller and an amplifier to generate 1/2VDDR voltage for VTT and VTTR. The VTT and VTTR voltages are maintained within 1% of 1/2VDDR. The controller operates in synchronous rectification mode to ensure balanced current sourcing and sinking capability of up to 25A. With a shutdown current of less than 5µA, the MAX1917 is the best choice for low-power notebook applications, as well as servers and desktop computers. An all N-FET design optimizes efficiency. The MAX1917 can also be used for generating VDDR and as a general-purpose step-down controller with variable switching frequency as high as 1MHz with few additional components.

    The MAX1917 uses Maxim's proprietary Quick-PWM™ architecture for fast transient response up to 96% efficiency, and the smallest external components. Output current monitoring is achieved without sense resistors by monitoring the bottom FET's drain-to-source voltage. The current-limit threshold is programmable through an external resistor. The MAX1917 comes in a space-saving 16-pin QSOP package.

    Simplified Block Diagram

    MAX1917: Typical Operating Circuit MAX1917: Typical Operating Circuit 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 .