MAX8643A

3A, 2MHz Step-Down Regulator with Integrated Switches

Smallest, Most-Efficient 3A Step-Down Regulator Up to a 2.4MHz Frequency


Please check latest availability status for a specific part variant.

Description

The MAX8643A high-efficiency switching regulator delivers up to 3A load current at output voltages from 0.6V to (0.9 x VIN). The IC operates from 2.35V to 3.6V, making it ideal for on-board point-of-load and postregulation applications. Total output error is less than ±1% over load, line, and temperature.

The MAX8643A features fixed-frequency PWM mode operation with a switching frequency range of 500kHz to 2MHz set by an external resistor. High-frequency operation allows for an all ceramic capacitor design. The high operating frequency also allows for small-size external components.

The low-resistance on-chip nMOS switches ensure high efficiency at heavy loads while minimizing critical inductances, making the layout a much simpler task with respect to discrete solutions. Following a simple layout and footprint ensures first-pass success in new designs.

The MAX8643A comes with a high-bandwidth (> 14MHz) voltage-error amplifier. The voltage-mode control architecture and the voltage-error amplifier permit a type III compensation scheme to be utilized to achieve maximum loop bandwidth, up to 20% of the switching frequency. High loop bandwidth provides fast transient response, resulting in less required output capacitance and allowing for all-ceramic capacitor designs.

The MAX8643A provides two three-state logic inputs to select one of nine preset output voltages. The preset output voltages allow customers to achieve ±1% output-voltage accuracy without using expensive 0.1% resistors. In addition, the output voltage can be set to any customer value by either using two external resistors at the feedback with 0.6V internal reference or applying an external reference voltage to the REFIN input. The MAX8643A offers programmable soft-start time using one capacitor to reduce input inrush current. The MAX8643A is available in a lead-free, 24-pin, 4mm x 4mm thin QFN package.
MAX8643A: Typical Operating Circuit MAX8643A: Typical Operating Circuit Enlarge+

Key Features

  • Internal 37mΩ RDSON MOSFETs
  • Continuous 3A Output Current
  • ±1% Output Accuracy Over Load, Line, and Temperature
  • Operates from 2.35V to 3.6V Supply
  • Adjustable Output from 0.6V to (0.9 x VIN)
  • Soft-Start Reduces Inrush Supply Current
  • 500kHz to 2MHz Adjustable Switching Frequency
  • Compatible with Ceramic, Polymer, and Electrolytic Output Capacitors
  • VID-Selectable Output Voltages
    • 0.6, 0.7, 0.8, 1.0, 1.2, 1.5, 1.8, 2.0, and 2.5V
  • Fully Protected Against Overcurrent and Overtemperature
  • Safe-Start into Prebiased Output
  • Sink/Source Current in DDR Applications
  • Lead-Free, 24-Pin, 4mm x 4mm Thin QFN Package

Applications/Uses

  • ASIC/CPU/DSP Core and I/O Voltages
  • Base-Station Power Supplies
  • DDR Power Supplies
  • POLs
  • RAID Control Power Supplies
  • Telecom and Networking Power Supplies
Part NumberVIN
(V)
VIN
(V)
VOUT1
(V)
VOUT1
(V)
Output Adjust. MethodIOUT1
(A)
Switch TypeSynchronous SwitchingPower Good SignalDC-DC OutputsOper. Freq.
(kHz)
Design ToolsPackage/PinsBudgetary
Price
minmaxminmaxSee Notes
MAX8643A 2.353.60.62.5
Digital/VID
Dyn. REF In
Preset
Resistor
3InternalYesYes12000EE-Sim
TQFN/24
$3.26 @1k
See All Step-Down Switching Regulators (367)
Pricing 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 and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Technical Documents

User Guide 5861 EE-SIM Design and Simulation Environment User Guide

Quality and Environmental Data

Product Reliability Reports: MAX8643A.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Tools & Models

  • EE-Sim: Design & Simulate MAX8643A
  • MAX8643A SIMPLIS Schematic
  • CAD Symbols and Footprints

  • MAX8643AETG+
  • MAX8643AETG+T
  • MAX8643AETG/V+
  • MAX8643AETG/V+T
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >

     
    Status:
    Package:
    Temperature:

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