# how to find bias so that OP amp output range is max?

#### only6512

Feb 15, 2014
18
hello,everyone , i have a question about (d) i just know that maxium output may be V_Bp2+|Vov7| mininum:V_BN2-v_ov9 can anyone help me? thanks ^^

*by the way ,i want to check the answer to (c) my answer:max:5-|V_ov4|+V_t1;min:-5+|V_ov3|+|V_ov1|+V_t1 are my answers right? thans again^^

#### Attachments

• 31.jpg
40.8 KB · Views: 130

#### Arouse1973

Dec 18, 2013
5,178
Can you explain What V_0V4 and V_t1 is. I would have thought for the max you should be taking away all relevant voltage and not adding them as in -V_t1 and not +V_t1? What are these voltages?

#### Arouse1973

Dec 18, 2013
5,178
Ah just figured your Vt1 is what is called VTN and is the threshold voltage. I am not sure but I think it should be this
Max = VDD-VSD4+VTN and Min = VSS+VSD3+VGS1

#### only6512

Feb 15, 2014
18
V_ov4 is the overdrive voltage of mosfet 4
V_t1 is the threshold voltage of mosfet 1
Max = VDD-VSD4+VTN and Min = VSS+VSD3+VGS1
I think it is the same as mine:
5-|V_ov4|+V_t1;min:-5+|V_ov3|+|V_ov1|+V_t1

#### Arouse1973

Dec 18, 2013
5,178
Yep Correct. I think the other question is asking you what bias voltages you need on the gates of the depletion Mosfets to give half supply point on the output, and in this case I think the output should be 0V. The other guys might read this differently. I think they mean symmetry and not actually maximum or minimum voltage.

Replies
2
Views
1K
Replies
9
Views
273
Replies
8
Views
262
Replies
9
Views
361
Replies
1
Views
280