LOG114, for higher input current

Kamal Najmi

Expert 3435 points

Other Parts Discussed in Thread: LOG114

hi my customer want to use this part with higher input current.

From 10nA TO 100mA photo diode.

VOLTAGE SHOULD BE BETWEEN 2.5 and 5.5V

Current mirror doesn't work due to the VBE drop.

Could you please help?

kamal

over 12 years ago

0 JP Norair over 12 years ago

Intellectual 630 points

Did you find the answer? I am interested in the same thing. I should add that I only care about measuring low currents (100nA - 1mA), but my input includes transient currents up to 20mA. it would be nice to know if LOG114 can have input current <10mA without dying, even if the measurement is useless.

0 Kamal Najmi over 12 years ago in reply to JP Norair

TI__Expert 3435 points

SORRY for my late answer, actually i didn't get a positive feedback.

so no solution at the moment

0 JP Norair over 12 years ago in reply to Kamal Najmi

Intellectual 630 points

Alternately, do you know of a design for a current mirror that can use 100nA-100mA (or even 1uA to 100mA) in a divide-by-10 configuration? This would be perfectly fine as I am not using LOG114 to measure current on a photodiode, but I have not been able to come up with a suitable current mirror.

Thanks

0 Kamal Najmi over 12 years ago in reply to JP Norair

TI__Expert 3435 points

Actually i do not have a complete solution but using standard current mirror, you can divide your current.

The LOG114 is specified until 10ma MAX , I am not sure it can stand 20ma.

Regards

kamal

Amplifiers

Amplifiers forum

LOG114, for higher input current