LM134: LM334; LM134

Sumeet Patil

Part Number: LM134
Other Parts Discussed in Thread: REF102, REF70, REF54

Tool/software:

Hi,

I want a very stable precision current source for JFET tail biasing. The current source should have a positive temperature coefficient to cancel out the negative temperature coefficient of JFET gm.

The current rating is 4 mA.

Also please note that entire design operates on +/- 15V, so tail current source will have it reference connected to -15V rail.

Also noise is very important, so the noise addition should be very low, in few fA.

Please suggest me a good way to achieve this. I look forward to hearing from you soon.

9 months ago

0 Masoud Beheshti61 9 months ago

TI__Mastermind 18121 points

We apologize for extended delay due to year-end holidays. Your post will be answered in the next 10-12 days.

0 Andrew Li 9 months ago

TI__Expert 4220 points

Hi Sumeet,

Thanks for your question!

Below are a few app notes that detail how to design precision current sources with voltage references.

https://www.ti.com/lit/an/snoaa46/snoaa46.pdf

https://www.ti.com/lit/an/sbva001/sbva001.pdf

https://www.ti.com/lit/an/sboa046/sboa046.pdf

The REF102 example (second link) can also be expanded to other series voltage references that may be used to meet your specs.

I hope this helps!

Best Regards,

Andrew Li

0 Sumeet Patil 9 months ago in reply to Andrew Li

Prodigy 250 points

Hi Andrew,

I am looking for a very low noise and positive tempco current source, could you let me know, what would be suitable part for the same.

0 Andrew Li 9 months ago in reply to Sumeet Patil

TI__Expert 4220 points

Hi Sumeet,

My recommendation would be the LMx34 family of devices, but the noise level of this device is in the pA range.

https://www.ti.com/product/LM134

If the LMx34 cannot be used in your application, I would recommend the REF54 or REF70 series voltage references which can be used to create a current source.

I hope this helps!

Best Regards,

Andrew Li

Power management

Power management forum

LM134: LM334; LM134