0
\$\begingroup\$

I simulated circuit which consist of a trans impedance amplifier ,some multistage amplifiers and filters.In my first circuit TIA used is AD8067 and for other parts I used TL074 op amp from TI.This circuit was working perfectly in LT spice. After this I replaced TL074 with OPA1664 and TIA remains the same.But for this circuit I am getting an error as shown below.

Singular matrix: Check nodes d:u3:u2:1#int1 and u1:13 Iteration No. 2 Fatal Error: Singular matrix: check nodes d:u3:u2:1#int1 and u1:13 Iteration No. 2

Circuit diagram and screen shot of error file are attached along with this mail. enter image description here

I connected a 1GIG Resistance from non inverting point to ground.But the problem still exists.

I am attaching the circuit files along with this mail.Circuit 1.Its op is connected to ip of circuit 2.Circuit 2 its op is connected to ip of circuit 3![][1]

enter image description here


I connected a 1GIG Resistance from non inverting point to ground.But the problem still exists. I am attaching the circuit files along with this mail.Circuit 1.Its op is connected to ip of circuit 2.Circuit 2 its op is connected to ip of circuit 3![][1]

enter image description here

\$\endgroup\$
  • \$\begingroup\$ Your circuit diagram is not readable. Can you read it ? \$\endgroup\$ – efox29 May 18 '15 at 7:29
1
\$\begingroup\$

"Singular Matrix" issues are usually resolved by adding a 1GIG resistor to ground. It means "a current is too small to calculate." Try adding one from net d:u3:u2:1 to ground. (I can't read it either.)

\$\endgroup\$
  • \$\begingroup\$ LTSpice is funny about "1GIG." It must be typed as "1GIG", not "1G". Try that. \$\endgroup\$ – rdtsc Sep 10 '15 at 0:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.