DS1721

Digital Thermometer and Thermostat

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Status Explanations for product status codes

Active: In Production.

Description

The DS1721 digital thermometer and thermostat features ±1°C accuracy over a -10°C to +85°C range. Thermometer data is read out over a 2-wire serial bus in 2's complement format with 9 to 12 bits of resolution (user-programmable). The DS1721 features three address inputs, allowing users to multidrop up to eight DS1721 devices on one bus.

The DS1721 offers thermostatic functionality with over-temperature (TH) and under-temperature (TL) user-programmable trip-points stored in on-chip SRAM. The two trip-points provide programmable thermostat hysteresis: the thermostat output is asserted when the measured temperature exceeds TH and it remains active until the temperature falls below TL.

The DS1721 is available in 150mil 8-pin SO (DS1721S) and 8-pin µMAX/µSOP (DS1721U) packages. For applications requiring higher precision, the DS1631 provides ±0.5°C accuracy and is functionally compatible with the DS1721.
 

Data Sheet

Download this datasheet in PDF formatDownload Rev 3 (PDF, 264kB)
Send this datasheet to any email addressE-Mail

Key Features

  • ±1°C accuracy from -10°C to +85°C
  • Measures temperatures from -55°C to +125°C (-67°F to +257°F)
  • 9- to 12-bit user-configurable resolution
  • Dedicated thermostatic logic output
  • Thermostatic settings are user-programmable
  • Data is transferred over 2-wire/SMBus interface
  • Three address inputs allow up to eight DS1721 to operate on one bus
  • 2.7V to 5.5V supply range
  • 150mil 8-pin SO (DS1721S) and 8-pin µMAX/µSOP (DS1721U) packages
 

Applications/Uses

  • Alarm Systems
  • Fibre Channel
  • Instrumentation
  • Networking
   

Key Specifications:

Temperature Sensors
Part Number Sensor Type Interface Accuracy
(±°C)
Parasite Pwr. Temp. Thresh. Temp. Resolution
(bits)
Multi Droppable Oper. Temp.
(°C)
Smallest Available Pckg.
(mm2)
Budgetary Price
max w/pins See Notes
DS1721  Local 2-Wire/I2C/SMBus 1 No Programmable
9
10
11
12
Yes -55 to +125 16.2 $1.69 @1k
See All Temperature Sensors (103)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


Diagram

DS1721: Functional Block Diagram
Functional Block Diagram

Application Notes

Application Note 127   Reverse Compatibility of the DS1721 Digital Temperature Sensor with the DS1621
Application Note 3930   Package Thermal Resistance Values (Theta JA, Theta JC) for Dallas Semiconductor Temperature Sensors
Tutorial 4679   Thermal Management Handbook

Product Guides

Thermal Management (PDF)

Reliability Reports

Reliability Report: DS1721.pdf

Software/Models

none

Ordering Information

Filters: Part Number: Package: Temperature: Tape and Reel Sample
Part Number Free
Sample
Buy Status Explanations for product status codes Package:
TYPE PINS FOOTPRINT
DRAWING  CODE/VAR *
Temp RoHS/Lead-Free?
Materials Analysis
DS1721S    
Active SOIC(N);8 pin;30.9 mm²
Outline Drawing:21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-2*
-55°C to +125°C RoHS/Lead-Free: No
Materials Analysis
DS1721S+  
Active SOIC(N);8 pin;30.9 mm²
Outline Drawing:21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+2*
-55°C to +125°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS1721S+T&R    
Active SOIC(N);8 pin;30.9 mm²
Outline Drawing:21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+2*
-55°C to +125°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS1721S/T&R    
Active SOIC(N);8 pin;30.9 mm²
Outline Drawing:21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-2*
-55°C to +125°C RoHS/Lead-Free: No
Materials Analysis
DS1721S/T&R+W    
Active SOIC(N);8 pin;30.9 mm²
Outline Drawing:21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+2*
-55°C to +125°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS1721U    
Active µMAX;8 pin;16.2 mm²
Outline Drawing:21-0036 (PDF)
Land Pattern: 90-0092 (PDF)
Use pkgcode/variation: U8-1*
-55°C to +125°C RoHS/Lead-Free: No
Materials Analysis
DS1721U+  
Active µMAX;8 pin;16.2 mm²
Outline Drawing:21-0036 (PDF)
Land Pattern: 90-0092 (PDF)
Use pkgcode/variation: U8+1*
-55°C to +125°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS1721U+T&R    
Active µMAX;8 pin;16.2 mm²
Outline Drawing:21-0036 (PDF)
Land Pattern: 90-0092 (PDF)
Use pkgcode/variation: U8+1*
-55°C to +125°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS1721U/T&R    
Active µMAX;8 pin;16.2 mm²
Outline Drawing:21-0036 (PDF)
Land Pattern: 90-0092 (PDF)
Use pkgcode/variation: U8-1*
-55°C to +125°C RoHS/Lead-Free: No
Materials Analysis
DS1721U/T&R+W    
Active µMAX;8 pin;16.2 mm²
Outline Drawing:21-0036 (PDF)
Land Pattern: 90-0092 (PDF)
Use pkgcode/variation: U8+1*
-55°C to +125°C RoHS/Lead-Free: Lead Free
Materials Analysis

Notes:
  1. Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
  2. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
  3. Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product Naming Conventions.
  4. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

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Rev 3; 2005-11-07
This page last modified: 2009-10-23


 


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