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4.5V to 28V Input, Synchronous PWM Buck Controllers for DDR Termination and Point-of-Load Applications

4.5V to 28V Input, Synchronous PWM Buck Controllers for DDR Termination and Point-of-Load Applications Offer Fastest Transient Response

Product Details

Key Features

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 28
VOUT1 (V) (min) 0.6
VOUT1 (V) (max) 3.5
IOUT1 (A) (max) 25
Switch Type External
Output Adjust. Method Resistor
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 550
Package/Pins QSOP/16
Budgetary
Price (See Notes)
2.48
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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) 0.6
VOUT1 (V) (max) 3.5
IOUT1 (A) (max) 25
Switch Type External
Output Adjust. Method Resistor
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 550
Package/Pins QSOP/16
Budgetary
Price (See Notes)
2.48

Key Features

  • Up to 25A Output-Current Capability
  • Quick-PWM Control for Fast Loop Response
  • Up to 95% Efficiency
  • 4.5V to 28V Input Voltage Range
  • No External Bias Supply Required
  • 0 to 3.6V Input REFIN Range (MAX8553)
  • Automatically Sets VTT and VTTR to within ±1% of 1/2 VREFIN- (MAX8553)
  • Low 0.6V Feedback Threshold (MAX8554)
  • 200kHz/300kHz/400kHz/550kHz Selectable Switching Frequencies
  • Adjustable Foldback Current Limit
  • Overvoltage Protection
  • Digital Soft-Start

Applications/Uses

  • AGTL Bus Termination Supplies
  • ASIC and CPU Core Voltages
  • DDR I and DDR II Memory Power Supplies
  • Notebook and LCD-PC Power Supplies
  • Servers and Storage Applications
  • Wide-Input Power Supplies

Description

The MAX8553 is a 4.5V to 28V input-voltage, synchronous step-down controller that provides a complete power-management solution for DDR memory. The MAX8553 generates 1/2 VREFIN voltage for VTT and VTTR. The VTT and VTTR tracking voltages are maintained within 1% of 1/2 VREFIN. The MAX8554 is a 4.5V to 28V input-voltage, nontracking step-down controller with a low 0.6V feedback threshold voltage. The MAX8553/MAX8554 use Maxim's proprietary Quick-PWM™ architecture for fast transient response and operate with selectable pseudo-fixed frequencies. Both controllers can operate without an external bias supply.

The controllers operate in synchronous-rectification mode to ensure balanced current sourcing and sinking capability of up to 25A. The MAX8553/MAX8554 also provide up to 95% efficiency, making them ideal for server and point-of-load applications. Additionally, a low 5µA shutdown current allows for longer battery life in notebook applications. Lossless current monitoring is achieved by monitoring the low-side MOSFET's drain-to-source voltage. The MAX8553/MAX8554 have an adjustable foldback current limit to withstand a continuous output overload and short circuit. Digital soft-start provides control of inrush current during power-up. Overvoltage protection shuts the converter down and discharges the output capacitor. The MAX8553/MAX8554 come in space-saving 16-pin QSOP packages.

Simplified Block Diagram

MAX8553, MAX8554: Typical Operating Circuit MAX8553, MAX8554: 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 .