Rainbow-electronics MAX6649 User Manual download pdf

General Description

The MAX6649 is a precise, two-channel digital temper-

ature sensor. It accurately measures the temperature of

its own die and a remote PN junction, and reports the

temperature in digital form using a 2-wire serial inter-

face. The remote PN junction is typically the emitter-

base junction of a common-collector PNP on a CPU,

FPGA, or ASIC.

The 2-wire serial interface accepts standard System

Management Bus (SMBus)™ write byte, read byte,

send byte, and receive byte commands to read the

temperature data and to program the alarm thresholds.

To enhance system reliability, the MAX6649 includes an

SMBus timeout. A fault queue prevents the ALERT and

OVERT outputs from setting until a fault has been

detected one, two, or three consecutive times

(programmable).

The MAX6649 provides two system alarms: ALERT and

OVERT. ALERT asserts when any of four temperature

conditions are violated: local overtemperature, remote

overtemperature, local undertemperature, or remote

undertemperature. OVERT asserts when the temperature

rises above the value in either of the two OVERT limit reg-

isters. The OVERT output can be used to activate a cool-

ing fan, or to trigger a system shutdown.

Measurements can be done autonomously, with the

conversion rate programmed by the user, or in a single-

shot mode. The adjustable conversion rate allows the

user to optimize supply current and temperature

update rate to match system needs.

Remote accuracy is ±1°C maximum error between +60°C

and +145°C with no calibration needed. The MAX6649

operates from -55°C to +125°C, and measures tempera-

tures between 0°C and +145°C. The MAX6649 is avail-

able in an 8-pin µMAX package.

Applications

Graphics Processors

Desktop Computers

Notebook Computers

Servers

Thin Clients

Workstations

Test and Measurement

Multichip Modules

Features

♦ Dual Channel: Measures Remote and Local

Temperature

♦ 0.125°C Resolution

♦ High Accuracy ±1°C (max) from +60°C to +145°C

(Remote), and ±2°C (max) from +60°C to +100°C

(Local)

♦ Two Alarm Outputs: ALERT and OVERT

♦ Programmable Under/Overtemperature Alarm

Temperature Thresholds

♦ Programmable Conversion Rate

♦ SMBus-Compatible Interface

♦ SMBus Timeout

MAX6649

+145°C Precision SMBus-Compatible Remote/

Local Sensor with Overtemperature Alarms

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

DXP

DXN

10kΩ EACH

CLOCK

TO FAN DRIVER OR

SYSTEM SHUTDOWN

3.3V

DATA

INTERRUPTED TO µP

200Ω

0.1µF

SDA

SCLK

ALERT

GND

2200pF

µP

MAX6649

OVERT

Typical Operating Circuit

19-2540; Rev 0; 8/02

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.

PART

TEMP RANGE

PIN-

PACKAGE

MEASURED

TEMP RANGE

MAX6649MUA

-55°C to +125°C

8 µMAX

0°C to +145°C

SMBus is a trademark of Intel Corp.

Pin Configuration and Functional Diagram appear at end of

data sheet.

1 2 3 4 5 6 ... 14 15

Summary of Contents

Page 1 - Typical Operating Circuit

General DescriptionThe MAX6649 is a precise, two-channel digital temper-ature sensor. It accurately measures the temperature ofits own die and a remot

Page 2 - ELECTRICAL CHARACTERISTICS

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms10 ___________________________________________________________

Page 3

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms______________________________________________________________

Page 4 - = 3.3V, T

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms12 ___________________________________________________________

Page 5 - Pin Description

3) Route the DXP and DXN traces in parallel and inclose proximity to each other, away from any highervoltage traces, such as 12VDC. Leakage currentsfr

Page 6 - SMBus Digital Interface

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms14 ___________________________________________________________

Page 7 - Alarm Threshold Registers

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature AlarmsMaxim cannot assume responsibility for use of any circuitry ot

Page 8 - Alert Response Address

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms2 ____________________________________________________________

Page 9

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms______________________________________________________________

Page 10 - POR and UVLO

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms4 ____________________________________________________________

Page 11 - Applications Information

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms______________________________________________________________

Page 12 - Manufacturers

MAX6649The worst-case DXP-DXN differential input voltagerange is 0.25V to 0.95V. Excess resistance in series withthe remote diode causes +0.5°C (typ)

Page 13 - Thermal Mass and Self-Heating

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms______________________________________________________________

Page 14 - Chip Information

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms8 ____________________________________________________________

Page 15 - Package Information

MAX6649+145°C Precision SMBus-Compatible Remote/Local Sensor with Overtemperature Alarms______________________________________________________________

Rainbow-electronics MAX6649 User Manual

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Rainbow-electronics MAX6649 User Manual

Browse online or download User Manual for Sensors Rainbow-electronics MAX6649. Rainbow Electronics MAX6649 User Manual

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