MAXIM MAX6687, 6688 User Manual

General Description

The MAX6687/MAX6688 comprise a remote-junction
temperature switch and a local temperature switch in a
single package. The remote-junction switch uses an
external P-N junction (typically a diode-connected tran­sistor on the die of an external CPU, ASIC, or FPGA) as
a sensing element to measure the remote temperature.
The remote-junction temperature switch has a factory­programmed trip temperature threshold of either
+120°C or +125°C. The local temperature switch has a
pin-programmable temperature threshold that is set by
connecting pins S1 and S2 to ground, to VDD, or leav­ing them floating. Hysteresis for both local and remote
thresholds is 5°C. The MAX6687/MAX6688 do not
assert on transient (single-sample) faults or when
power is first applied.

The MAX6687 has two open-drain active-low outputs
while the MAX6688 has two push-pull active-high out­puts. T

REMOTE

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

LOCAL

is asserted when the
die temperature exceeds the pin-programmed thresh­old, which is controlled by pins S1 and S2. The local
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.

The MAX6687/MAX6688 operate from a 3.0V to 5.5V
power supply and are available in a space-saving 8-pin
µMAX package.

Applications

CPU Temperature Protection

FPGA Temperature Protection

Fan Control

Temperature Alarms

Features

♦ Pin-Programmable Local Temperature Threshold

in 5°C Increments in Two Distinct Ranges: +40°C
to +80°C and +75°C to +115°C

♦ Factory-Programmed Remote Threshold:

+120°C (L Suffix) or +125°C (H Suffix)

♦ Open-Drain Active-Low Outputs (MAX6687)

♦ CMOS Push-Pull, Active-High Outputs (MAX6688)

♦ ±1.5°C Accuracy

♦ 2Hz Temperature Sampling Rate

♦ 215µA Average Supply Current

♦ 3.0V to 5.5V Power-Supply Voltage

♦ 8-Pin µMAX Package

MAX6687/MAX6688

Local/Remote Temperature Switches in a

µMAX Package

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-2636; Rev 2; 11/03

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/Functional Diagrams/Selector Guide
appear at end of data sheet.

Typical Operating Circuit

3.3V

V

DD

DXP

MAX6687

C

S

DXN

µP µP

S1

S2

GND

T

REMOTE

T

LOCAL

3.3V

TO SYSTEM
SHUTDOWN

PART TEMP RANGE PIN-PACKAGE

MAX6687AU40L -40°C to +125°C 8 µMAX

MAX6687AU40H -40°C to +125°C 8 µMAX

MAX6687AU75L -40°C to +125°C 8 µMAX

MAX6687AU75H -40°C to +125°C 8 µMAX

MAX6688AU40L -40°C to +125°C 8 µMAX

MAX6688AU40H -40°C to +125°C 8 µMAX

MAX6688AU75L -40°C to +125°C 8 µMAX

MAX6688AU75H -40°C to +125°C 8 µMAX

C

S

DXP

DXN

S1

S2

3.3V

V

DD

MAX6688

GND

T

REMOTE

T

LOCAL

TO SYSTEM
SHUTDOWN

12V

N

MAX6687/MAX6688

Local/Remote Temperature Switches in a
µMAX Package

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= 3V 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
VDD, T

LOCAL

, T

REMOTE

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

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

All Other Pins..............................................-0.3V to (VDD+ 0.3V)

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

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

Continuous Power Dissipation (TA= +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

Power-Supply Range V

Average Supply Current I

Supply Current During
Conversion

Power-On Reset (POR) Threshold POR V

POR Threshold Hysteresis 50 mV

Remote-Diode Temperature
Threshold Accuracy, Rising
Temperature

Internal Temperature Threshold
Accuracy, Rising Temperature

Temperature Threshold
Hysteresis

Temperature Threshold Supply
Sensitivity

Output Voltage High V

Output Voltage Low V

Logic Input Low Voltage
(S1, S2)

Logic Input High Voltage
(S1, S2)

Input Current (S1, S2) 10 µA

Open-Drain Output Leakage
Current

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS

DD

DD

falling edge 1 1.5 2.0 V

DD

TA = +25°C, VDD = 3.3V -1.5 +1.5

∆T

∆T

T

HYST

V

V

TA = 0°C to +85°C, VDD = 3.3V -3.0 +3.0

TH

TA = -40°C to +125°C, VDD = 3.3V -5.0 +5.0

Temperature trip thresholds from +40°C to
+105°C, V

TH

Temperature trip thresholds +110°C and
+115°C, V

OHISOURCE

I

OL

SINK

IL

IH

V

OUT

DD

DD

= 1mA, MAX6688 V

= 1mA 0.2 V

= 5.5V, MAX6687 1 µA

3 5.5 V

215 500 µA

400 800 µA

= 3.3V

= 3.3V

-3.0 +3.0

-3.5 +3.5

5.0 °C

- 0.2 V

DD

1.8 V

0.6 °C/V

0.4 V

°C

°C

MAX6687/MAX6688

Local/Remote Temperature Switches in a

µMAX Package

_______________________________________________________________________________________ 3

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

ELECTRICAL CHARACTERISTICS (continued)

(VDD= 3V 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)

Typical Operating Characteristics

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

AVERAGE SUPPLY CURRENT

vs. AMBIENT TEMPERATURE

MAX6687/88 toc01

AMBIENT TEMPERATURE (°C)

AVERAGE SUPPLY CURRENT (µA)

1007550250-25

140

180

220

260

300

100

-50 125

AVERAGE SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX6687/88 toc02

SUPPLY VOLTAGE (V)

AVERAGE SUPPLY CURRENT (µA)

5.04.54.03.5

140

180

220

260

300

100

3.0 5.5

TA = +100°C

TA = -40°C

TA = +25°C

TEMPERATURE TRIP THRESHOLD ERROR

vs. C

S

CAPACITANCE

MAX6687/88 toc03

CS CAPACITANCE (nF)

TEMPERATURE TRIP THRESHOLD ERROR (°C)

10

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0

1 100

MAX6688U40H
S1 = S2 = FLOAT

REMOTE TEMPERATURE TRIP THRESHOLD

ERROR vs. AMBIENT TEMPERATURE

MAX6687/88 toc04

AMBIENT TEMPERATURE (°C)

UPPER TRIP THRESHOLD ERROR (°C)

7550250-25

-4

-3

-2

-1

0

1

-5

-50 100

MAX6688U40H
T

REMOTE

TRIP = +125°C

Temperature Conversion Time 0.2 0.25 0.3 s

Temperature Sample Period 0.4 0.5 0.6 s

Current Sourcing for External
Diode

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS

High level 80 100 120

Low level 8 10 12

µA