MAXIM MAX6685, MAX6686 Technical data

General Description

MAX6685/MAX6686 are dual-output temperature switches
that use an external diode-connected transistor as a sens­ing element. These devices have two logic outputs (T

HIGH

and T

LOW

). T

HIGH

asserts a logic signal when the remote
temperature crosses the factory-programmed, +120°C, or
+125°C upper trip threshold. T

LOW

is asserted when the
remote temperature exceeds the lower threshold, which is
controlled by pins S1 and S2. The lower thresholds are
available in two ranges in 5°C increments. The two ranges
are +40°C to +80°C and +75°C to +115°C. Hysteresis for
both outputs to be deasserted is typically 5°C.

T

HIGH

is an open-drain, active-low output for both the

MAX6685 and the MAX6686. T

LOW

is a CMOS push-pull,
active-high output for the MAX6685 and is an open-drain,
active-low output for the MAX6686. They are available in
a space-saving 8-pin µMAX package.

Applications

Features

♦ Pin-Programmed Lower Temperature Threshold

from +40°C to +80°C or +75°C to +115°C
(5°C Increments)

♦ Preset Upper Threshold: +120°C or +125°C

♦ Open-Drain, Active-Low Output for Upper

Temperature Alarm

♦ CMOS Push-Pull, Active-High or Open-Drain,

Active-Low Output for Lower Temperature Alarm

♦ 1.5°C Accuracy

♦ 3.0V to 5.5V, 200µA Supply

♦ 8-Pin µMAX Package

MAX6685/MAX6686

Dual-Output Remote-Junction

Temperature Switches

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

MAX6685

C

S

12V

GND

CPU

S1

DXN

S2

3.3V

TO SYSTEM
SHUTDOWN

N

T

LOW

DXP

V

DD

T

HIGH

MAX6686

C

S

GND

CPU

S1

DXN

S2

3.3V

TO SYSTEM
SHUTDOWN

TO CLOCK
THROTTLE

CONTROL

T

LOW

DXP

V

DD

T

HIGH

Typical Operating Circuits

19-2459; Rev 2; 4/03

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.

Pin Configurations appear at end of data sheet.

CPU Temperature
Protection

Fan Control

Multichip Modules
FPGA Temperature

Protection

T

PART

MAX6685AU40L Push-pull, active high +40°C to +80°C +120°C 8 µMAX

MAX6685AU40H Push-pull, active high +40°C to +80°C +125°C 8 µMAX

MAX6685AU75L Push-pull, active high +75°C to +115°C +120°C 8 µMAX

MAX6685AU75H Push-pull, active high +75°C to +115°C +125°C 8 µMAX

MAX6686AU40L Open drain, active low +40°C to +80°C +120°C 8 µMAX

MAX6686AU40H Open drain, active low +40°C to +80°C +125°C 8 µMAX

MAX6686AU75L Open drain, active low +75°C to +115°C +120°C 8 µMAX

MAX6686AU75H Open drain, active low +75°C to +115°C +125°C 8 µMAX

LOW

OUTPUT

TRIP

T

LOW

RANGE (0°C)

T

TRIP

HIGH

THRESHOLD (0°C)

PIN-PACKAGE

MAX6685/MAX6686

Dual-Output Remote-Junction
Temperature Switches

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= 3.0V to 5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VDD= 3.3V and TA= +25°C.) (Note 1)

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.

Voltages Referenced to GND
V

DD, TLOW

, T

HIGH

.....................................................-0.3V to +6V

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

All Other Pins..............................................-0.3V to (V

DD

+ 0.3V)

Input Current .........................................................................5mA

Output Current ....................................................................20mA

Continuous Power Dissipation (T

A

= +70°C)

8-Pin µMAX (derate 4.1mW/°C above +70°C) .............330mW

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

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

Storage Temperature Range .............................-65°C to +165°C

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

Note 1: All parameters are tested at +25°C. Temperature specifications over a range of -40°C to +125°C are guaranteed by design.
Note 2: T

RJ

is the temperature of the remote-sensing diode junction.

Power-Supply Range V

Average Supply Current I

Supply Current During
Conversion

Power-On Reset Threshold POR V

POR Threshold Hysteresis 50 mV

Temperature Threshold
Accuracy

Temperature Threshold
Hysteresis

Supply Sensitivity of Temperature
Threshold

Output Voltage High V

Output Voltage Low V

Logic-Low Input Voltage V

Logic-High Input Voltage V

Input Current S1, S2 10 µA

Open-Drain Output Leakage
Current

Conversion Time 0.09 0.11 0.13 s

Sample Period 0.35 0.45 0.55 s

Current Sourcing for External
Diode

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS

DD

DD

falling edge 1.0 1.5 2.0 V

DD

VDD = 3.3V, TA = +25°C, TRJ = 0°C to +125°C

∆T

T

HYST

(Note 2)

TH

TA = 0°C to +100°C, TRJ = 0°C to +125°C 2.0

TA = +25°C, TRJ = 0°C to +125°C,
V

= 3.0V to 5.5V

DD

OHISOURCE

OLISINK

S1, S2 0.4 V

IL

S1, S2 1.8 V

IH

V

High level 80 100 120

Low level 8 10 12

= 1mA, MAX6685 T

= 1mA 0.2 V

OUT

= 5.5V, T

LOW

and T

HIGH

LOW

only

3.0 5.5 V

200 500 µA

400 800 µA

-1.5 +1.5

5.0 °C

0.6 °C/V

V

-

DD

0.2

1µA

°C

V

µA

MAX6685/MAX6686

Dual-Output Remote-Junction

Temperature Switches

_______________________________________________________________________________________ 3

Typical Operating Characteristics

(VDD= 3.3V, CS= 2200pF, TA= +25°C, unless otherwise noted. See Typical Operating Circuits.)

AVERAGE SUPPLY CURRENT

vs. AMBIENT TEMPERATURE

200

180

160

140

120

AVERAGE SUPPLY CURRENT (µA)

100

-50 125
AMBIENT TEMPERATURE (°C)

UPPER TEMPERATURE TRIP THRESHOLD

2.0

1.6

1.2

0.8

0.4

0

-0.4

-0.8

-1.2

UPPER TRIP THRESHOLD ERROR (°C)

-1.6

-2.0

-50 125

250

MAX6685 toc01

200

150

100

AVERAGE SUPPLY CURRENT (µA)

1007550250-25

ERROR vs. AMBIENT TEMPERATURE

MAX6685U40H

TRIP = +125°C

T

HIGH

AMBIENT TEMPERATURE (°C)

AVERAGE SUPPLY CURRENT

vs. SUPPLY VOLTAGE

50

0

3.0 5.5
SUPPLY VOLTAGE (V)

5.04.54.03.5

LOWER TEMPERATURE TRIP THRESHOLD

ERROR vs. AMBIENT TEMPERATURE

2.0

MAX6685U40H

1.6

MAX6685 toc04

1007525 500-25

S1 = S2 = V

1.2

0.8

0.4

0

-0.4

-0.8

-1.2

LOWER TRIP THRESHOLD ERROR (°C)

-1.6

-2.0

-50 125

10

MAX6685 toc02

TEMPERATURE TRIP THRESHOLD ERROR (°C)

DD

AMBIENT TEMPERATURE (°C)

TEMPERATURE TRIP THRESHOLD ERROR

MAX6685U40H
S1 = S2 = GND

8

6

4

2

0

060

1007525 500-25

CAPACITANCE

vs. C

S

CS CAPACITANCE (nF)

MAX6685 toc05

MAX6685 toc03

5040302010