LM4132: Load Independent 5mA constant current source (Load Resistance 650 ohm to 750 ohm).

Rajesh Matere

Part Number: LM4132

Hi,

We are looking for Load Independent constant current source, Load current value will be 5mA. Load resistance will vary from 650 Ohm to 850 Ohm. Input power is 5V.

Also, it should have lower temperature coefficient, because this is going to be implemented in Sensor application.

I do have size constraint on board, so I am looking for less component solution. While working on TI website, I found following design.

Will this work as Load independent ( 650R to 850R) 5mA constant current source?

Thank you,

Regards,

Rajesh Matere.

over 6 years ago

0 Marcoo Z over 6 years ago

TI__Mastermind 19370 points

Hi Rajesh,

There should be no issue in doing this. The LM4132 can source up to 20mA of current and should have no problem with 5mA.

How much accuracy do you need on this current source?

-Marcoo Z

0 Rajesh Matere over 6 years ago in reply to Marcoo Z

Prodigy 205 points

Hi Marcoo,

Accuracy should be less than 1% and temperature coefficient should be less than 20ppm/deg C.

Thank you,

Regards,

Rajesh M.

0 Marcoo Z over 6 years ago in reply to Rajesh Matere

TI__Mastermind 19370 points

Hi Rajesh,

I believe this would be your best shot at a current source. I believe this way of doing a current source might be valid in other voltage references with lower ppm/C but I haven't tested them yet.

-Marcoo

0 Rajesh Matere over 6 years ago in reply to Marcoo Z

Prodigy 205 points

Hi Marcoo,

Okay.

Thank you for your support, I have ordered some samples, I will test it and let you know.

Regards,

Rajesh M.

0 kai klaas69 over 6 years ago

Guru 140200 points

Hi Rajesh Matere,

the circuit is thought to have RL close to the LM4132. If RL is far away from the LM4132, cable impedances will ruin the effectiveness of Cin. This could result in instability.

Kai

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LM4132: Load Independent 5mA constant current source (Load Resistance 650 ohm to 750 ohm).