Guys,
did anyone came across an analog or digital temperature sensor that has an operating voltage range of 1.8V - 5V and preferably in a TO92 package (smd is of if it’s not to small to solder by hand)
Greetings,
Eric
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Have not tried it, but there is an LM60 @ 2.7v, and others just Google TO92 Temperature sensor.
Is this a trick question?
The standard answer, of course, is a Maxim DS18B20. 3.0V-5.5V operating voltage range, digital, programmable resolution, available in TO-92, uSOP, and SO packages. $5.99 in ones from DigiKey, but can be had for under $1 per (shipped) in 5s on eBay. -55C to +125C sensing range, 0.5C accuracy, resolution programmable from 9 to 12 bits.
As a bonus, multiple sensors can be connected to a single line.
No this is not a trick question.
I need the sensor to be still working at 2V. A DS18B20 stops working when the supply voltage goes below 2.5V
I’m working on a 2xAA battery powered wireless sensor so it has to be capable of measuring at least till the batteries reach 2V.
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What temerature range do you need? And what accuracy?
-20 to +50 at 0.1°C resolution (also 0.5°C is acceptable)
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Aha, ok, now I understand. You don’t need something that works somewhere in that voltage range, you need something that works EVERYWHERE in that voltage range.
I doubt it, the Gadgeteer mainboard would stop working long before you hit 2V.
Digi-Key says:
[quote]The TMP20 is a CMOS, precision analog output temperature sensor available in the tiny SOT563 package. The TMP20 operates from –55°C to +130°C on a supply voltage of 2.7V to 5.5V with a supply current of 4μA. Operation as low as 1.8V is possible for temperatures between +15°C and +130°C. The linear transfer function has a slope of –11.77mV/°C (typ) and has an output voltage of 1.8639V (typ) at 0°C. The TMP20 has a ±2.5°C accuracy across the entire specified temperature range of –55°C to +130°C.
The TMP20 4μA (max) supply current limits self-heating of the device to less than 0.01°C. When V+ is less than 0.5V, the device is in shutdown mode and consumes less than 20nA (typ). The TMP20 is available in either a 5-lead SC70 or 6-lead SOT563 package, reducing the overall board space required.[/quote]
There’s nothing available there with the sort of accuracy you’re looking for. Is something like an RTD or a plain ol’ thermistor an option?
Use a step-up buck dc-dc converter, it will transform any dc value between 0.8 and 3v3 to a stable 3v3 voltage with an efficiency of 95%. F.e: http://be02.rs-online.com/web/p/boost-converters/0516502/
The one in the link needs some external components, but I’m sure if you search a bit, you’ll find one that only needs a coil , a schottky diode and a cap.