General Description

The DS28EA00 is a digital thermometer with 9-bit (0.5°C)

to 12-bit (1/16°C) resolution and alarm function with non-

volatile (NV), user-programmable upper and lower trigger

points. Each DS28EA00 has its own unique 64-bit regis-

tration number that is factory programmed into the chip.

which requires only one data line and a ground reference

for communication. The improved 1-Wire front-end with

hysteresis and glitch filter enables the DS28EA00 to per-

form reliably in large 1-Wire networks. Unlike other 1-Wire

thermometers, the DS28EA00 has two additional pins to

implement a sequence-detect function. This feature

allows the user to discover the registration numbers

according to the physical device location in a chain, e.g.,

to measure the temperature in a storage tower at different

height. If the sequence-detect function is not needed,

these pins can be used as general-purpose input or out-

put. The DS28EA00 can derive the power for its operation

directly from the data line (“parasite power”), eliminating

the need for an external power supply.

Applications

Data Communication Equipment

Process Temperature Monitoring

HVAC Systems

Features

♦ Digital Thermometer Measures Temperatures

from -40°C to +85°C

♦ Thermometer Resolution is User Selectable from

9 to 12 Bits

♦ Unique 1-Wire Interface Requires Only One Port

Pin for Communication

♦ Each Device Has a Unique 64-Bit, Factory-

Lasered Registration Number

♦ Multidrop Capability Simplifies Distributed

Temperature-Sensing Applications

♦ Improved 1-Wire Interface with Hysteresis and

Glitch Filter

♦ User-Definable NV Alarm Threshold Settings/User

Bytes

♦ Alarm Search Command to Quickly Identify

Devices Whose Temperature is Outside of

Programmed Limits

♦ Standard and Overdrive 1-Wire Speed

♦ Two General-Purpose Programmable IO (PIO) Pins

♦ Chain Function Sharing the PIO Pins to Detect

Physical Sequence of Devices in Network

♦ Operating Range: +3.0V to +5.5V, -40°C to +85°C

♦ Can Be Powered from Data Line

♦ 8-Pin µSOP Package

1-Wire Digital Thermometer with

Sequence Detect and PIO

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

DS28EA00

IO

PIOB

PIOA

GND

NOTE: SCHEMATIC SHOWS PIO PINS WIRED FOR SEQUENCE-DETECT FUNCTION.

1-Wire

MASTER

#1

DS28EA00

IO

PIOB

PX. Y

MICROCONTROLLER

PIOA

GND

#2

DS28EA00

IO

PIOB

PIOA

GND

#3

Typical Operating Circuit

Rev 2; 4/09

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN-PACKAGE

DS28EA00U+

-40

°C to +85°C

8 μSOP

DS28EA00U+T&R

-40

°C to +85°C

8 μSOP

Pin Configuration appears at end of data sheet.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

T&R = Tape and reel.

1-Wire is a registered trademark of Maxim Integrated Products, Inc.