staric
Member level 4
where can find a current reference circuit with zero TC? I read some papers. The method is to find the sum of PTAT current and invert PTAT current. And Is there any other method?
Humungus said:Current references with zero TC is nearly imposible. Why? Because you always generate a current based on a resistor which has a finite non-zero TC. You can try making the resistor with two materials, one with positive TC and the other with negative one. Then, preview a triming mechanism and trim your circuit at the test stage.
Humungus said:Current references with zero TC is nearly imposible. Why? Because you always generate a current based on a resistor which has a finite non-zero TC. You can try making the resistor with two materials, one with positive TC and the other with negative one. Then, preview a triming mechanism and trim your circuit at the test stage.
staric said:Humungus said:Current references with zero TC is nearly imposible. Why? Because you always generate a current based on a resistor which has a finite non-zero TC. You can try making the resistor with two materials, one with positive TC and the other with negative one. Then, preview a triming mechanism and trim your circuit at the test stage.
But when the two type resistor are be changed to different corner(fast and slow) in the process, the current ref. value will shift a lot.