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MAX8855
Dual, 5A, 2MHz Step-Down Regulator

Smallest, Most Efficient 5A Regulator with Integrated Switches in 5mm x 5mm TQFN Package


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Data Sheet
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Description
The MAX8855 high-efficiency, dual step-down regulator is capable of delivering up to 5A at each output. The device operates from a 2.35V to 3.6V supply, and provides output voltages from 0.6V to 0.9 x VIN, making it ideal for on-board point-of-load applications. Total output error is less than ±1% over load, line, and temperature.

The MAX8855 operates in PWM mode with a switching frequency ranging from 0.5MHz to 2MHz, set by an external resistor. It can also be synchronized to an external clock in the same frequency range. Two internal switching regulators operate 180° out-of-phase to reduce the input ripple current, and consequently reduce the required input capacitance. The high operating frequency minimizes the size of external components. High efficiency, internal dual-nMOS design keeps the board cool under heavy loads. The voltage-mode control architecture and the high-bandwidth (> 15MHz typ) voltage-error amplifier allow a type III compensation scheme to be utilized to achieve fast response under both line and load transients, and also allow for ceramic output capacitors.

Programmable soft-start reduces input inrush current. Two enable inputs allow the turning on/off of each output individually, resulting in great flexibility for systemlevel designs. A reference input is provided to facilitate output-voltage tracking applications. The MAX8855 is available in a 32-pin thin QFN (5mm x 5mm) package with 0.8mm max height.

Key Features   Applications/Uses
  • 27mΩ On-Resistance Internal MOSFETs
  • Dual, 5A, PWM Step-Down Regulators
  • Fully Protected Against Overcurrent, Short Circuit, and Overtemperature
  • ±1% Output Accuracy over Load, Line, and Temperature
  • Operates from 2.35V to 3.6V Supply
  • REFIN on One Channel for Tracking or External Reference
  • Integrated Boost Diodes
  • Adjustable Output from 0.6V to 0.9 x VIN
  • Soft-Start Reduces Inrush Supply Current
  • 0.5MHz to 2MHz Adjustable Switching, or FSYNC Input
  • All-Ceramic-Capacitor Design
  • 180° Out-of-Phase Operation Reduces Input Ripple Current
  • Individual Enable Inputs and PWRGD Outputs
  • Available in 5mm x 5mm Thin QFN Package
  • Sink/Source Current in DDR Applications

 
  • ASIC/CPU/DSP Power Supplies
  • DDR Power Supplies
  • Network Power Supplies
  • Printer Power Supplies
  • Set-Top Box Power Supplies

    Key Specifications:   Step-Down Switching Regulators
    Part Number VIN (min) (V) VIN (max) (V) Min. VOUT (V) Max. VOUT (V) IOUT (A) Output Adj. Method Operating Current, ICC (max) (mA) Number of DC-DC Outputs Operating Freq. (kHz) Features EV-Kit Package RoHS Available Operating Temp. Range (°C) Price**
    MAX8855  2.35 3.6 0.6 3.3 5 Resistor 3.5 2 2000
    Adjustable Frequency
    Current Limit
    Dual/Multi-Phase Controller
    External Synchronization
    Fixed Frequency/ PWM Operation
    Internal Power Switches
    Low Battery/ Power OK Output
    Shutdown
    Soft Start
    Synchronous Rectifier
    No THIN QFN/32 Yes -40 to +85 $4.55 @ 1k
    See All Step-Down Switching Regulators (223)

    Key Specifications:   Switch-Mode DC-DC Power Supplies
    Part Number Topology VIN (min) (V) VIN (max) (V) Number of DC-DC Outputs Digital/VID Programmed Output Min. Adjustable VOUT (V) Max. Adjustable VOUT (V) IOUT (A) Operating Current, ICC (max) (mA) Operating Freq. (kHz) Internal Power Switch(es) Package Price**
    MAX8855  Step-Down 2.35 3.6 2 No 0.6 3.3 5 3.5 2000 Yes THIN QFN/32 $4.55 @ 1k
    See All Switch-Mode DC-DC Power Supplies (429)
    Notes:
    **This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

    Diagram
    MAX8855: Typical Operating Circuit
    Typical Operating Circuit

    Evaluation Kits
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    Software/Models
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    Ordering Information
    Notes:

    1. Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
    2. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
    3. Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
    4. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.


    Devices: 1-3 of 3

    MAX8855 Free
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    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    Temp RoHS/Lead-Free?
    Materials Analysis
    MAX8855EVKIT+  



    See data sheet
    MAX8855ETJ+T  



    -40°C to +85°C See data sheet
    MAX8855ETJ+  
    THIN QFN;32 pin;
    Dwg: 21-0140L (PDF)
    Use pkgcode/variation: T3255+4*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis

    More Information
  • New Product Press Release 2007-12-10 
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    Document Ref.: 19-0726; Rev 1; 2008-06-19
    This page last modified: 2008-06-24



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