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MAX745
Switch-Mode Lithium-Ion Battery-Charger

±0.75% Precision Li+ Charger Delivers 4A Without Heating


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Status
Active: In Production.

Data Sheet
FULL DATA SHEET (PDF, 144kB)
Download this datasheet in PDF formatDownload   Send this datasheet to any email addressE-Mail

Description
The MAX745 provides all functions necessary for charging lithium-ion (Li+) battery packs. It provides a regulated charging current of up to 4A without getting hot, and a regulated voltage with only ±0.75% total error at the battery terminals. It uses low-cost, 1% resistors to set the output voltage, and a low-cost N-channel MOSFET as the power switch.

The MAX745 regulates the voltage set point and charging current using two loops that work together to transition smoothly between voltage and current regulation. The per-cell battery voltage regulation limit is set between 4V and 4.4V using standard 1% resistors, and then the number of cells is set from 1 to 4 by pin-strapping. Total output voltage error is less than ±0.75%.

For a similar device with an SMBus™ microcontroller interface and the ability to charge NiCd and NiMH cells, refer to the MAX1647 and MAX1648. For a low-cost Li+ charger using a linear-regulator control scheme, refer to the MAX846A.

An evaluation kit is available:  MAX745EVKIT  

Key Features   Applications/Uses
  • Charges 1 to 4 Li+ Battery Cells
  • ±0.75% Voltage-Regulation Accuracy Using 1% Resistors
  • Provides up to 4A without Excessive Heating
  • 90% Efficient
  • Uses Low-Cost Set Resistors and N-Channel Switch
  • Up to 24V Input
  • Up to 18V Maximum Battery Voltage
  • 300kHz Pulse-Width Modulated (PWM) Operation Low-Noise, Small Components
  • Stand-Alone Operation—No Microcontroller Needed

 
  		• Cell Phones
  		• Desktop Cradle Chargers
  		• Handheld Instruments (PDAs, Palmtops)
  		• Li+ Battery Packs
  		• Notebook Computers

    Key Specifications:  Battery Chargers
    Part Number Cell Chemistry Lithium Ion Cells Protected VIN
    (V)    		 Charging VIN
    (V)    		 Charge Rate Set by Max. ICHG
    (A)    		 Charge Termination Charge Regulation Features EV Kit Package/Pins Smallest Available Pckg.
    (mm2)    		 Oper. Temp.
    (°C)    		 Price
    max max ≥ max w/pins See Notes
    MAX745 
    Li-Ion
    Li-Polymer
    1
    2
    3
    4
    		 24 24 Resistor 4
    Current Limit
    Max. Voltage
    		 Switchmode
    Stand Alone
    Thermistor Input
    		 Yes
    SSOP/20
    		 58 -40 to +85 $4.50 @1k
    See All Battery Chargers (62)

    Diagram
    MAX745: Typical Operating Circuit
    Typical Operating Circuit

    Application Notes
  		• Application Note 680: How to Design Battery Charger Applications that Require External Microcontrollers and Related System-Level Issues - MAX745
  		• Application Note 721: Portable Devices Need High-Performance Battery Chargers - MAX745

    Evaluation Kits
  		• MAX745EVKIT

    Reliability Reports
  		• Reliability Report: MAX745.pdf
  		• Show FIT data for:

    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: 1-5 of 5

    MAX745 Free
    Sample    		 Buy Status
    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    		Temp RoHS/Lead-Free?
    Materials Analysis
    MAX745C/D    
    		Active

    Land Pattern: Not Available

    		See data sheet
    MAX745EAP    
    		Active SSOP;20 pin;58 mm²
    Outline Drawing: 21-0056 (PDF)
    Land Pattern: 90-0094 (PDF)
    Use pkgcode/variation: A20-1*
    		-40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis
    MAX745EAP-T    
    		Active SSOP;20 pin;58 mm²
    Outline Drawing: 21-0056 (PDF)
    Land Pattern: 90-0094 (PDF)
    Use pkgcode/variation: A20-1*
    		-40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis
    MAX745EAP+  
    		Active SSOP;20 pin;58 mm²
    Outline Drawing: 21-0056 (PDF)
    Land Pattern: 90-0094 (PDF)
    Use pkgcode/variation: A20+1*
    		-40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    MAX745EAP+T    
    		Active SSOP;20 pin;58 mm²
    Outline Drawing: 21-0056 (PDF)
    Land Pattern: 90-0094 (PDF)
    Use pkgcode/variation: A20+1*
    		-40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis

    Related Products
    MAX846A Cost-Saving, Multichemistry, Battery Charger System
    MAX1782 Advanced Smart Battery-Pack Controller
    MAX1647, MAX1648 Chemistry-Independent Battery Chargers
    MAX1640, MAX1641 Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier

    More Like This: View Product Families for Similar Products

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    Document Ref.: 19-1182; Rev 3; 2002-09-10
    This page last modified: 2007-05-31


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