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Active: In Production.

Data Sheet

FULL DATA SHEET (PDF, 216kB) Download   E-Mail

Description

The MAX6643/MAX6644/MAX6645 monitor temperature and automatically adjust fan speed to ensure optimum cooling while minimizing acoustic noise from the fan. Each device measures two temperature locations. The MAX6643/MAX6644/MAX6645 generate a PWM waveform that drives an external power transistor, which in turn modulates the fan's power supply. The MAX6643/MAX6644/MAX6645 monitor temperature and adjust the duty cycle of the PWM output waveform to control the fan's speed according to the cooling needs of the system. The MAX6643 monitors its own die temperature and an optional external transistor's temperature, while the MAX6644 and MAX6645 each monitor the temperatures of one or two external diode-connected transistors. The MAX6643 and MAX6644 have nine selectable trip temperatures (in 5°C increments). The MAX6645 is factory programmed and is not pin selectable. All versions include an overtemperature output (active-low OT). Active-low OT can be used for warning or system shutdown. The MAX6643 also features a FULLSPD input that forces the PWM duty cycle to 100%. The MAX6643/MAX6644/MAX6645 also feature a active-low FANFAIL output that indicates a failed fan. See the Selector Guide in the full data sheet for a complete list of each device's functions. The MAX6643 and MAX6644 are available in a small 16-pin QSOP package and the MAX6645 is available in a 10-pin µMAX® package. All versions operate from 3.0V to 5.5V supply voltages and consume 500µA (typ) supply current.

An evaluation kit is available:  MAX6643LBEVKIT  

Key Features		Applications/Uses
Simple, Automatic Fan-Speed Control Internal and External Temperature Sensing Detect Fan Failure Through Locked-Rotor Output, Tachometer Output, or Fan-Supply Current Sensing Multiple, 1.6% Output Duty-Cycle Steps for Low Audibility of Fan-Speed Changes Pin-Selectable or Factory-Selectable Low-Temperature Fan Threshold Pin-Selectable or Factory-Selectable High-Temperature Fan Threshold Spin-Up Time Ensures Fan Start Fan-Start Delay Minimizes Power-Supply Load at Power-Up 32Hz PWM Output Controlled Duty-Cycle Rate-of-Change Ensures Good Acoustic Performance 2°C Temperature-Measurement Accuracy Active-Low FULLSPD/FULLSPD Input Sets PWM to 100% Pin-Selectable Active-Low OT Output Threshold 16-Pin QSOP and 10-Pin µMAX Packages		Desktop Computers Networking Equipment Servers Storage Equipment Workstations

Diagram

Block Diagram

Application Notes

Application Note 1057: Compensating for Ideality Factor and Series Resistance Differences between Thermal Sense Diodes - MAX6643, MAX6644, MAX6645 Application Note 3502: Effect of PC Board Trace Width on Remote-Diode Temperature-Sensor Accuracy - MAX6643, MAX6644, MAX6645

Evaluation Kits

MAX6643LBEVKIT

Design Guides

Thermal Management (PDF)

Reliability Reports

Reliability Report: MAX6644.pdf Show FIT data for: MAX6643 MAX6644 MAX6645 Request Reliability Report for: MAX6643 MAX6645

Software/Models

none

Ordering Information

Notes: Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day. Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions. * 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: 1-17 of 17

MAX6643	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX6643LBFAEE+			Active	QSOP;16 pin;31 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16+1*	-40°C to +125°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX6643LBFAEE+T			Active	Land Pattern: Not Available	-40°C to +125°C	See data sheet
MAX6643LBBAEE+T			Active	QSOP;16 pin;31 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16+1*	-40°C to +125°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX6643LBBAEE+			Active	QSOP;16 pin;31 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16+1*	-40°C to +125°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX6643LBBAEE			Active	QSOP;16 pin;31 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16-1*	-40°C to +125°C	RoHS/Lead-Free: No Materials Analysis
MAX6643LBBAEE-T			Active	Land Pattern: Not Available	-40°C to +125°C	See data sheet
MAX6644	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX6644LBAAEE+			Active	QSOP;16 pin;31 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16+1*	-55°C to +125°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX6644LBAAEE+T			Active	QSOP;16 pin;31 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16+1*	-55°C to +125°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX6644LBAAEE			Active	QSOP;16 pin;31 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16-1*	-55°C to +125°C	RoHS/Lead-Free: No Materials Analysis
MAX6644LBAAEE-T			Active	Land Pattern: Not Available	-55°C to +125°C	See data sheet
MAX6645	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX6645AAFAUB			Active	µMAX;10 pin;15 mm² Outline Drawing: 21-0061 (PDF) Land Pattern: 90-0330 (PDF) Use pkgcode/variation: U10-2*	-55°C to +125°C	RoHS/Lead-Free: No Materials Analysis
MAX6645ABFAUB			Active	µMAX;10 pin;15 mm² Outline Drawing: 21-0061 (PDF) Land Pattern: 90-0330 (PDF) Use pkgcode/variation: U10-2*	-55°C to +125°C	RoHS/Lead-Free: No Materials Analysis
MAX6645ABFAUB+			Active	µMAX;10 pin;15 mm² Outline Drawing: 21-0061 (PDF) Land Pattern: 90-0330 (PDF) Use pkgcode/variation: U10+2*	-55°C to +125°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX6645ABFAUB+T			Active	Land Pattern: Not Available	-55°C to +125°C	See data sheet
MAX6645ABFAUB-T			Active	Land Pattern: Not Available	-55°C to +125°C	See data sheet
MAX6645BAFAUB+			Active	µMAX;10 pin;15 mm² Outline Drawing: 21-0061 (PDF) Land Pattern: 90-0330 (PDF) Use pkgcode/variation: U10+2*	-55°C to +125°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX6645BAFAUB+T			Active	Land Pattern: Not Available	-55°C to +125°C	See data sheet

More Information

New Product Press Release 2004-05-04

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