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Measuring Zo in TINA SPICE. Tim Green Precision Linear Analog Applications January 2, 2014. OPA735 Reference Buffer. L1 is short at DC and allows SPICE to find the proper DC Operating point – necessary before AC Analysis. C1 is open at DC but Short at AC for any frequency of interest. - PowerPoint PPT Presentation
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Measuring Zo in TINA SPICE
Tim Green
Precision Linear Analog Applications
January 2, 2014
1
OPA735 Reference Buffer
2
Vdd 5
L1 1T
V1 2.5IG1
VF1
+
-
+
U1 OPA735
C1 1T
2.5V
L1 is short at DC and allows SPICE to find the proper DC Operating point – necessary before AC Analysis.C1 is open at DC but Short at AC for any frequency of interest.IG1 is AC Current Generator with 0A for DC Current.For AC Analysis VF1 will be Zo(dB). Change dB scale to Logarithmic for Zo(ohms)
OPA735 Zo(dB)
3
T
Ga
in (
dB
)
40.00
50.00
60.00
70.00
80.00
90.00
Frequency (Hz)
1 10 100 1k 10k 100k 1M 10M
Ph
ase
[de
g]
-90.00
-75.00
-60.00
-45.00
-30.00
-15.00
0.00
OPA735 Zo(dB)
OPA735 Zo(ohms)
4
OPA735 Zo(ohms)
5
OPA735 Zo(ohms)
6
T
Ga
in (
dB
)
100.00
1.00k
10.00k
100.00k
Frequency (Hz)
1 10 100 1k 10k 100k 1M 10M
Ph
ase
[de
g]
-90.00
-75.00
-60.00
-45.00
-30.00
-15.00
0.00
OPA735 Zo(ohms)
