Recommendation for temperature sensor needed!

[fireflies]

thermistor ibutton ds1920

Hi, could someone kindly recommend a suitable temperature sensor with or without celsius to voltage converter bearing the following spects. :

I need it for measuring skin temperature for the project im doing.

1) Extremely low current of approximately 1 microampere and below
2) Low supply voltage < 2V
3) High accuracy of 0.5 degree celsius.

I've tried national semiconductors, farnell as well as texas intruments and they do no have it. Any recommendations of a temperature sensor?

thanks

 

[klystron]

Use the AD590

 

[IanP]

An interesting option is the 1-Wire® protocol ..

Take a look at DS1920 temperature sensor: **broken link removed**

The DS1920 provides direct-to-digital 9-bit temperature readings over a range of -55°C to +100°C in 0.5° increments. The iButton® communicates with a processor using the 1-Wire® protocol through a hardware port interface. The port interface provides both the physical link and handles the communication protocols that enable the processor to access iButton resources with simple commands. Two bytes of EEPROM can be used either to set alarm triggers or for storing user data.

The same protocol is used by temperature data loggers: **broken link removed**
For example, one of a range of datalogging iButtons, the DS1921, houses a battery and an embedded computer chip that integrates a temperature sensor, a clock/calendar and memory .. and all enclosed in a 16mm stainless steel can ..

Regards,
IanP

 

[lambtron]

Use a thermistor. You will get the best accuracy and response time. Response time is much faster than semiconductor solutions because you can get very small thermistors and, hence low thermal mass (and fast settling time).

 

[PaulHolland]

Hi, Whatever sensor you select take one that has the smallest size. Why ?. Since it is small it will be more sensitive and as a result faster giving you a stable temperature value. You don't want a patient to wait 2 minutes do you ????.. So NO: SOIC packages or like. Why not taking a normal 1N4148 diode ???.. is giving -2mV/K

Paul.

 

[mmike]

Thermo Couple is another type.,

 

[lambtron]

Thermo Couple is another type.,

Thermocouples do have low voltage, but you will find them to be fairly expensive and hard to find if you seek tc's with fast thermal response. Also, skin has a relatively narrow temperature range and so you probably will not get the sensitivity you need from a tc; this is where thermistors really shine.

 

[mmike]

Check this ... It may help ...

National Semiconductor Temperature Sensor Handbook
This handbook provides an introduction to temperature sensing, ... Integrated circuit temperature sensors differ significantly from the other types


www.national.com/appinfo/tempsensors/files/temphb2.pdf