MAXIM MAX6668, MAX6670 Technical data

General Description

The MAX6668/MAX6670 remote-junction thermal switches with an internal power transistor drive a cooling fan rated for supply voltages up to +12V and 250mA. These devices measure the temperature of an external P-N junction (typically a diode-connected transistor) and turn on the fan power switch when the remote temperature rises above a factory-programmed threshold. Self-contained and requiring no software development, the MAX6668/MAX6670 are simple “drop-in” fan-control solutions for a variety of systems.

The MAX6670 features an open-drain WARN output that goes active when the remote temperature exceeds the factory-programmed fan activation threshold by +15°C. The MAX6670 features an open-drain OT output that goes active when the remote temperature exceeds the factory-programmed threshold by +30°C. The MAX6668/MAX6670 provide a fan-control input, FORCEON, that allows the fan to be driven externally, regardless of temperature.

Available temperature thresholds range from +40°C to +75°C in 5°C increments. Hysteresis is preset to 8°C on the MAX6668 or pin selectable to 4°C, 8°C, or 12°C using a three-level logic input on the MAX6670. Temperature threshold accuracy is ±1°C (typ) and ±2.2°C (max) for remote-junction temperatures from +40°C to +75°C.

The MAX6668/MAX6670 operate from a +3V to +3.6V power supply, and are specified over the automotive temperature range (-40°C to +125°C). The MAX6668 is offered in an 8-pin µMAX package and the MAX6670 is available in a space-saving 10-pin µMAX package.

Applications

Notebook and Desktop Computers

Network Switches

PC Power Supplies

Laboratory Instruments

Card Racks

Temperature Alarms

Fan Controls

Features

♦ +12V, 250mA Integrated Fan Driver

♦ No Calibration Required

♦ Pin-Selectable 4°C, 8°C, or 12°C Hysteresis

(MAX6670)

♦ Factory-Programmed Temperature Thresholds

from +40°C to +75°C

♦ Overtemperature Warning Signals

♦ 110µA (typ) Supply Current

♦ Space-Saving 8-Pin and 10-Pin µMAX Packages

MAX6668/MAX6670

Remote Temperature Switches with Integrated

Fan Controller/Driver

________________________________________________________________ Maxim Integrated Products 1

Typical Application Circuit

Ordering Information

19-2133; Rev 2; 11/02

Pin Configuration appears at end of data sheet.

Typical Operating Circuit appears at end of data sheet.

Ordering Information continued at end of data sheet.

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

查询MAX6668供应商

PART

MAX6668AUA40 -40°C to +125°C 8 µMAX 40

MAX6668AUA45 -40°C to +125°C 8 µMAX 45

MAX6668AUA50 -40°C to +125°C 8 µMAX 50

MAX6668AUA60 -40°C to +125°C 8 µMAX 60

MAX6668AUA70 -40°C to +125°C 8 µMAX 70

MAX6668AUA75 -40°C to +125°C 8 µMAX 75

TEMP

RANGE

PI N -

PA C K A G E

T H R ESH -

O L D

( ° C )

+12V

250mA

FAN

10kΩ

2N3904

2200pF

+3.3V

DXP

DXN

MAX6670

FANOUT

WARN

FORCEON

HYST

GND

PGND

MAX6668/MAX6670

Remote Temperature Switches with Integrated Fan Controller/Driver

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +3V to +3.6V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VDD= +3.3V and TA= +25°C.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

VDDto GND..............................................................-0.3V to +6V

PGND to GND .......................................................-0.3V to +0.3V

FANOUT to GND ....................................................-0.3V to +15V

DXN to GND ..........................................................-0.3V to +0.8V

DXP, WARN, HYST, FORCEON, OT...........-0.3V to (V

+ 0.3V)

Current into V

, GND, DXP, DXN, WARN, HYST,

FORCEON, OT..............................................................±20mA

Current into FANOUT, PGND ........................................ ±300mA

Continuous Power Dissipation (T

= +70°C)

8-Pin µMAX (derate 4.1mW/°C above +70°C).............333mW

10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW

Operating Temperature Range .........................-40°C to +125°C

Storage Temperature Range .............................-60°C to +150°C

Junction Temperature......................................................+150°C

Lead Temperature (soldering, 10s) .................................+300°C

POWER SUPPLY

Power-Supply Range V

Average Supply Current I

Operating Current During sampling 400 650 µA

Power-On Reset (POR) Threshold POR VDD falling edge 1 1.5 2.0 V

POR Threshold Hysteresis 50 mV

TEMPERATURE SENSOR

FANOUT Temperature Threshold Accuracy

FANOUT Temperature Threshold Hysteresis

WARN Temperature Threshold (MAX6670 Only)

OT Temperature Threshold (MAX6670 Only)

Supply Sensitivity of Temperature Threshold

Temperature Sample Frequency 3.3 4 Hz

FAN DRIVE OUTPUT

FANOUT Output Voltage Low V

Thermal Shutdown 170 °C

Thermal Shutdown Hysteresis 20 °C

LOGIC INPUT/OUTPUT

FORCEON Input High Voltage V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

TRJ = +40°C to +75°C (Note 1), T

= 0°C to +85°C, VDD = +3.3V

∆T

HYST

TRJ = +40°C to +75°C (Note 1), T

= -40°C to +125°C, VDD = +3.3V

HYST = GND 4

MAX6670

MAX6668 8

Relative to FANOUT temperature threshold +15 °C

Relative to FANOUT temperature threshold +30 °C

= 250mA 0.5 1 V

SINK

HYST = float 8

HYST = V

3 3.6 V

110 200 µA

±1 ±2.2

±1 ±4

1 1.6 °C/V

0.8 x V

°C

MAX6668/MAX6670

Remote Temperature Switches with Integrated

Fan Controller/Driver

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +3V to +3.6V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VDD= +3.3V and TA= +25°C.)

Note 1: T

is the temperature of the remote P-N junction.

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

0.2

0.1

0.4

0.3

0.6

0.5

0.7

0 100 15050 200 250 300

FANOUT CURRENT

vs. FANOUT VOLTAGE

MAX6668/70 toc01

FANOUT

(mA)

FANOUT

(V)

TA = +25°C

VDD = +3.3V

0.6

0.4

0.2

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.0 2.5

3.0

3.5

FANOUT VOLTAGE

vs. SUPPLY VOLTAGE

MAX6668/70 toc02

VDD (V)

FANOUT

(V)

TA = +105°C

TA = +65°C

TA = +25°C

FANOUT

= 250mA

120

100

140

SUPPLY CURRENT

vs. TEMPERATURE

MAX6668/70 toc03

TEMPERATURE (°C)

(µA)

0 255075100

VDD = +3.3V, I

FANOUT

= 250mA

120

100

140

3.0 3.63.3

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX6668/70 toc04

VDD (V)

(µA)

FORCEON = V

-1.00

-0.25

-0.50 0.50-0.75 0 0.25 0.75

1.00

TEMPERATURE THRESHOLD ERROR

MAX6668/70 toc05

THRESHOLD ERROR (°C)

PERCENTAGE OF SAMPLES (%)

MAX6670AUB040 119 SAMPLES

FORCEON Input Low Voltage V

FORCEON Input Bias Current V WARN, OT Output Voltage Low V

WARN, OT Output High Leakage

Current

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SINK

FORCEON

= VDD or GND 1 µA

= 6mA 0.5 V

or V OT = +5.5V 1 µA

WARN

0.2 x V

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