XTR 117!!!

Purushottam Pawar

Other Parts Discussed in Thread: XTR117, OPA735, OPA188

Hi,

I have assembled the circuit of XTR117 and tested with two diffrent power supplies (one power supply of 24V for transistor and another 0-5V variable supply as an input to XTR 117 ) and it is working fine.

In another case I have used 5V regulated supply of XTR117 for my amplification circuit and applied the output of this circuit (which is 0-3V) to input of XTR 117. In this case the output of XTR 117 is 9-20mA for 0-3V input . I have used TIP41C transistor.

Please advice how will I get 4-20mA output for required input range.

Thanks,

Paddy

over 12 years ago

0 Collin Wells over 12 years ago

TI__Guru 64385 points

Hello Paddy,

Please share a schematic with us so we can take a look at the circuit. Without seeing the schematic a first guess is that the circuitry being powered by the 5V regulated supply is consuming around 9mA which is why you can't output a level lower than that.

In 2-wire systems the current drawn by the loop circuitry must typically consume less than 3.5 mA so the low-level output of 4mA can be achieved. Systems that feature under-scale warning or error outputs ( < 4 mA) must consume even less current.

Please be sure that the correct part numbers are shown for your amplification stage so we can look up the operating current of them.

0 Purushottam Pawar over 12 years ago in reply to Collin Wells

Intellectual 400 points

Hi Collin,

Thanks a lot for your guidance!!!

Please find attached schematic. Kindly have a look and suggest.

Thanks,

Paddy

8322.Amplification circuit.pdf

0 Purushottam Pawar over 12 years ago in reply to Purushottam Pawar

Intellectual 400 points

Hi Collin,

You are right. The amplification section is consuming 9mA current.

Can you suggest any alternate low power consumption IC's for amplification circuit.

Thanks,

Paddy

0 Collin Wells over 12 years ago in reply to Purushottam Pawar

TI__Guru 64385 points

Hello Paddy,

What is the total supply voltage? It's a little hard to tell. If it's 12V or below, look at the OPA735 for the precision amplifiers, for 36V operation, look at the OPA188 for the precision parts and OPA234 for the more generic amplifiers.

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XTR 117!!!