Rainbow-electronics MAX6691 User Manual download pdf

General Description

The MAX6691 four-channel thermistor temperature-to-

pulse-width converter measures the temperatures of up

to four thermistors and converts them to a series of out-

put pulses whose widths are related to the thermistors’

temperatures. Each of the four thermistors and an

external fixed resistor (R

EXT

) form a voltage-divider that

is driven by the MAX6691’s internal voltage reference

REF

). V

REF

and the voltage across R

EXT

are mea-

sured and converted to a pulse.

The MAX6691 has a single open-drain I/O pin that can

be readily connected to a variety of microcontrollers.

The microcontroller initiates a conversion by pulling the

I/O pin low and releasing it. When conversion is done,

the MAX6691 signals the end of conversion by pulling

the I/O pin low once again. The pulse corresponding to

the first thermistor is sent immediately after the release

of the I/O pin.

The on-chip power-management circuitry reduces the

average thermistor current to minimize errors due to

thermistor self-heating. Between conversions, the

MAX6691 falls into a 10µA (max) sleep mode, where

the voltage reference is disabled and the supply cur-

rent is at its minimum.

The MAX6691 is available in a 10-pin µMAX package

and is specified from -55°C to +125°C temperature

range.

Applications

HVAC

Home Appliances

Medical Devices

Features

♦ Simple Single-Wire Interface

♦ Measures Up to Four Thermistor Temperatures

♦ Low-Average Thermistor Current Minimizes Self-

Heating Errors

♦ Internal Voltage Reference Isolates Thermistor

from Power-Supply Noise

♦ Accommodates Any Thermistor Temperature

Range

MAX6691

Four-Channel Thermistor Temperature-to-Pulse-

Width Converter

________________________________________________________________ Maxim Integrated Products 1

I/O

N.C.

GNDT4

MAX6691

µMAX

TOP VIEW

R+R-

Pin Configuration

I/O

N.C.

GND

MAX6691

TOP VIEW

R+

R-

MICRO-

CONTROLLER

10kΩ

EXT

Typical Application Circuit

19-2304; Rev 0; 1/02

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.

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX6691MUB -55°C to +125°C 10 µMAX

1 2 3 4 5 6 7

Width Converter 1

Summary of Contents

Page 1 - Width Converter

General DescriptionThe MAX6691 four-channel thermistor temperature-to-pulse-width converter measures the temperatures of upto four thermistors and con

Page 2

MAX6691Four-Channel Thermistor Temperature-to-Pulse-Width Converter2 _________________________________________________________________________________

Page 3

MAX6691Four-Channel Thermistor Temperature-to-Pulse-Width Converter___________________________________________________________________________________

Page 4

MAX6691Detailed DescriptionThe MAX6691 is an interface circuit that energizes up tofour thermistors and converts their temperatures to aseries of outp

Page 5

The relationship between temperature and resistanceof an NTC thermistor is highly nonlinear. However, byconnecting the thermistors in series with a pr

Page 6

MAX6691bypass VCCto GND by placing a 0.1µF to 1.0µFceramic bypass capacitor close to the supply pin of thedevices.Thermal ConsiderationsSelf-heating d

Page 7

MAX6691Four-Channel Thermistor Temperature-to-Pulse-Width ConverterMaxim cannot assume responsibility for use of any circuitry other than circuitry en

Comments to this Manuals

No comments

Rainbow-electronics MAX6691 User Manual

Browse online or download User Manual for Sensors Rainbow-electronics MAX6691. Rainbow Electronics MAX6691 User Manual

Summary of Contents

Comments to this Manuals

Related products and manuals for Sensors Rainbow-electronics MAX6691