| ??? 05/19/05 13:14 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#93607 - TI (Burr-Brown) App Note SBAA050 Responding to: ???'s previous message |
Ant Cosier said:
i have been looking on the internet for a current source but i am having dificulty finding one with least a 1% tolerance Take a look at TI (Burr-Brown) App Note SBAA050 "COMPLETE TEMPERATURE DATA ACQUISITION SYSTEM FROM A SINGLE +5V SUPPLY" Abstract: http://focus.ti.com/docs/apps...me=sbaa050 Direct Download: http://www-s.ti.com/sc/psheets/sbaa050/sbaa050.pdf This uses the ADC's reference voltage output to generate the drive current SBAA050 said:
The 2.5V reference output of the ADS574
is used to derive this current source, so that the entire system will be ratiometric. As the reference in the ADS574 changes over temperature or time, it will affect both the gain of the A/D and the current source. It also uses the RTD in 3-wire mode, to compensate for the effects of lead resistance - as Steve mentioned. (Note the slight mistake in Fig 2: there's a spurious line going straigh from the "top" RTD terminal to the A3 amplifier). |
| Topic | Author | Date |
| making a pt100 thermometer using a 8051 | 01/01/70 00:00 | |
| you are usually better off | 01/01/70 00:00 | |
| current sources | 01/01/70 00:00 | |
| TI (Burr-Brown) App Note SBAA050 | 01/01/70 00:00 | |
| That's great | 01/01/70 00:00 | |
| ads574 | 01/01/70 00:00 | |
| Indeed a very good link! | 01/01/70 00:00 | |
| calculating resistance | 01/01/70 00:00 | |
| Where are the problems, concretely? | 01/01/70 00:00 | |
| measuring resistance | 01/01/70 00:00 | |
| Use better mulitmeter... | 01/01/70 00:00 | |
| 2 multimeters | 01/01/70 00:00 | |
| max1410 | 01/01/70 00:00 | |
| Theoretical curve | 01/01/70 00:00 | |
| PT100 | 01/01/70 00:00 | |
| pt100s | 01/01/70 00:00 | |
| Look at LT1001data sheet | 01/01/70 00:00 | |
| wheatstone bridge | 01/01/70 00:00 | |
| Look at it this way..... | 01/01/70 00:00 | |
| anyone knows | 01/01/70 00:00 | |
| Keep it simple... | 01/01/70 00:00 | |
| So does Maxim | 01/01/70 00:00 | |
Already done... | 01/01/70 00:00 |