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MAX1945, MAX1945R, MAX1945S
1MHz, 1% Accurate, 6A Internal Switch Step-Down Regulators

Smallest 6A, 1MHz, 1%-Accurate Internal Switch Step-Down DC-DC


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Data Sheet
FULL DATA SHEET (PDF, 856kB)
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Description
The MAX1945R/MAX1945S high-efficiency pulse-width modulation (PWM) switching regulators deliver up to 6A of output current. The devices operate from an input supply range of 2.6V to 5.5V and provide selectable output voltages of 1.8V, 2.5V, and adjustable output voltages from 0.8V to 85% of the supply voltage. With VCC at 3.3V/5V, the input voltage can be as low as 2.25V. The MAX1945R/MAX1945S are ideal for on-board post-regulation applications. Total output voltage error is less than ±1% over load, line, and temperature.

The MAX1945R/MAX1945S operate at a selectable fixed frequency (500kHz or 1MHz) or can be synchronized to an external clock (400kHz to 1.2MHz). The high operating frequency minimizes the size of external components. The high bandwidth of the internal error amplifier provides excellent transient response. The MAX1945R/MAX1945S have internal dual N-channel MOSFETs to lower heat dissipation at heavy loads. Two MAX1945R/MAX1945Ss can operate 180 degrees out-of-phase of each other to minimize input capacitance. The devices provide output voltage margining for board-level testing. The MAX1945R provides a ±4% voltage margining. The MAX1945S provides a ±9% voltage margining.

The MAX1945R/MAX1945S are available in 28-pin TSSOP-EP packages and are specified over the -40°C to +85°C industrial temperature range. An evaluation kit is available to speed designs.

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Key Features   Applications/Uses
  • 6A PWM Step-Down Regulator with 95% Efficiency
  • 1MHz/500kHz Switching for Small External Components
  • 0.76in² Complete 6A Regulator Footprint
  • External Components' Height <3mm
  • ±1% Output Accuracy over Load and Line
  • Operate from 2.6V to 5.5V Supply
  • Operate from 2.5V Input with VCC at 3.3V/5V
  • Preset Output Voltage of 1.8V or 2.5V
  • Adjustable Output from 0.8V to 85% of Input
  • Voltage Margining: ±4% (MAX1945R) or ±9% (MAX1945S)
  • Synchronize to External Clock
  • SYNCOUT Provides 180-Degree Out-of-Phase Clock Output
  • All-Ceramic or Electrolytic Capacitor Designs

 
  • ASIC/CPU/DSP Core Voltages
  • Base Station-, Telecom-, and Networking-Equipment Power Supplies
  • Low-Voltage, High-Density Distributed Power Supplies
  • RAM Power Supply
  • Server and Notebook Power Supplies

    Key Specifications:   Step-Down Switching Regulators
    Part Number VIN (min) (V) VIN (max) (V) Min. VOUT (V) Max. VOUT (V) Preset VOUT (V) IOUT (A) IOUT (A) Output Adj. Method Operating Current, ICC (max) (mA) Number of DC-DC Outputs Operating Freq. (kHz) Package Price**
    MAX1945  2.6 5.5 0.8 4.5 1.8
    2.5
    6 6 Preset
    Resistor
    20 1 500 TSSOP/28 $4.20 @ 1k
    See All Step-Down Switching Regulators (223)
    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
    MAX1945R, MAX1945S: Typical Operating Circuit
    Typical Operating Circuit

    Application Notes
  • Application Note 1782: Small Footprint, 10us Response Time, 10mV Output Ripple, 1MHz, 6A Step-Down Regulator - MAX1945

    Evaluation Kits
  • MAX1945EVKIT

    Design Guides
  • Power Management for Battery-Powered Equipment (PDF)

    Reliability Reports
  • Show FIT data for:
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    Software/Models
    none

    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: 1-4 of 4

    MAX1945R Free
    Sample
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    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    Temp RoHS/Lead-Free?
    Materials Analysis
    MAX1945REUI  
    TSSOP;28 pin;
    Dwg: 21-0108 (PDF)
    Use pkgcode/variation: U28E-4*
    -40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis
    MAX1945REUI-T  
    TSSOP;28 pin;
    Dwg: 21-0108 (PDF)
    Use pkgcode/variation: U28E-4*
    -40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis
    MAX1945REUI+  
    TSSOP;28 pin;
    Dwg: 21-0108 (PDF)
    Use pkgcode/variation: U28E+4*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    MAX1945REUI+T  
    TSSOP;28 pin;
    Dwg: 21-0108 (PDF)
    Use pkgcode/variation: U28E+4*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis

    More Information
  • New Product Press Release 2002-12-02 
  • Product Family Ad: Download

    Related Products
    MAX1973, MAX1974 Smallest 1A, 1.4MHz Step-Down Regulators
    MAX1951, MAX1952 1MHz, All-Ceramic, 2.6V to 5.5V Input, 2A PWM Step-Down DC-to-DC Regulators

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    Document Ref.: 19-2640; Rev 1; 2004-08-24
    This page last modified: 2008-06-24



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