Update project tt_um_twin_tee_opamp_osc (mattvenn/tt07-twin-tee-opamp-osc)

projects/tt_um_twin_tee_opamp_osc/commit_id.json

@@ -1,8 +1,8 @@
 {
   "app": "custom_gds action",
   "repo": "https://github.com/mattvenn/tt07-twin-tee-opamp-osc",
-  "commit": "679f8d583d2104f1d07fd8ba8dfaaa82ca1fe039",
-  "workflow_url": "https://github.com/mattvenn/tt07-twin-tee-opamp-osc/actions/runs/9081112543",
+  "commit": "8b9cf6e482154dc52738359f92e437df6014e51c",
+  "workflow_url": "https://github.com/mattvenn/tt07-twin-tee-opamp-osc/actions/runs/9082788041",
   "sort_id": 1715697493814,
   "analog": true
 }

projects/tt_um_twin_tee_opamp_osc/docs/info.md

@@ -9,15 +9,39 @@ You can also include images in this folder and reference them in the markdown. E
 
 ## How it works
 
-https://www.youtube.com/watch?v=KFVVozlXoOk
+The circuit uses a "Twin Tee" filter along with an opamp to generate a sine wave.
+
 https://www.electronics-tutorials.ws/oscillator/twin-t-oscillator.html
 
-f = 1 / 2 * pi * RC
+    f = 1 / 2 * pi * RC
+
+### Notch filter AC analysis
+
+![Notch filter AC analysis](notch_ac.png)
+
+### Opamp AC analysis
+
+![Opamp AC analysis](p3_opamp_ac.png)
+
+### Transient analysis
+
+This simulation was done with a "montecarlo mismatch corner" which aims to test how well the circuit will work
+as the resistance and transistors change across process corners. Each run is shown in a different colour. If R6 resistor
+in the Twin Tee filter is too high, the oscillations quickly die out, so it's deliberately undersized at the expense of
+distortion in the sine wave.
+
+![Twin Tee output transient analysis](twin_trans.png)
+
+## Acknowledgements
+
+* The [opamp design comes from Sai](https://github.com/argunda/tt06-tiny-opamp)
+* The [opamp layout comes from Pat Deegan](https://github.com/psychogenic/tt06-analog-wowa)
+* Inspired by this video by [Alan Wolke](https://www.youtube.com/watch?v=KFVVozlXoOk). 
 
 ## How to test
 
 After the project is enabled, you should see a sine wave at around 6.3MHz on analog output pin 0.
 
 ## External hardware
 
-List external hardware used in your project (e.g. PMOD, LED display, etc), if any
+Oscilloscope.

projects/tt_um_twin_tee_opamp_osc/tt_um_twin_tee_opamp_osc.lef

@@ -935,12 +935,13 @@ MACRO tt_um_twin_tee_opamp_osc
         RECT 146.400 83.110 147.500 86.950 ;
         RECT 146.370 82.010 147.530 83.110 ;
         RECT 111.770 67.000 117.520 67.720 ;
-        RECT 144.460 49.500 145.240 49.750 ;
+        RECT 144.090 49.490 145.010 49.520 ;
         RECT 104.780 48.655 117.005 49.410 ;
-        RECT 144.000 49.370 146.950 49.500 ;
+        RECT 142.840 49.370 145.010 49.490 ;
         RECT 104.780 40.645 105.970 48.655 ;
-        RECT 139.690 48.590 146.950 49.370 ;
-        RECT 144.000 48.580 146.950 48.590 ;
+        RECT 139.690 48.590 145.010 49.370 ;
+        RECT 142.840 48.570 145.010 48.590 ;
+        RECT 144.090 48.540 145.010 48.570 ;
         RECT 110.750 45.250 112.250 45.280 ;
         RECT 124.400 45.250 148.650 45.900 ;
         RECT 110.750 43.750 148.650 45.250 ;
@@ -1293,7 +1294,7 @@ MACRO tt_um_twin_tee_opamp_osc
         RECT 111.075 68.045 112.265 69.235 ;
         RECT 146.400 82.010 147.500 83.110 ;
         RECT 111.800 67.000 112.520 67.720 ;
-        RECT 146.000 48.580 146.920 49.500 ;
+        RECT 144.090 48.570 145.010 49.490 ;
         RECT 137.650 42.850 138.650 43.150 ;
         RECT 129.200 40.850 130.050 41.200 ;
         RECT 129.100 40.550 130.050 40.850 ;
@@ -1403,10 +1404,9 @@ MACRO tt_um_twin_tee_opamp_osc
         RECT 107.070 67.000 112.520 67.720 ;
         RECT 107.070 66.955 107.790 67.000 ;
         RECT 111.800 66.970 112.520 67.000 ;
-        RECT 144.895 50.780 145.765 50.800 ;
-        RECT 144.870 49.860 146.920 50.780 ;
-        RECT 144.895 49.840 145.765 49.860 ;
-        RECT 146.000 48.550 146.920 49.860 ;
+        RECT 144.060 49.465 145.780 49.490 ;
+        RECT 144.060 48.595 145.800 49.465 ;
+        RECT 144.060 48.570 145.780 48.595 ;
         RECT 66.775 45.250 68.225 45.270 ;
         RECT 66.750 43.750 112.280 45.250 ;
         RECT 66.775 43.730 68.225 43.750 ;
@@ -1558,7 +1558,7 @@ MACRO tt_um_twin_tee_opamp_osc
         RECT 90.275 81.775 91.725 83.225 ;
         RECT 146.425 78.545 147.475 79.595 ;
         RECT 112.915 68.045 114.105 69.235 ;
-        RECT 144.895 49.885 145.765 50.755 ;
+        RECT 144.885 48.595 145.755 49.465 ;
         RECT 66.775 43.775 68.225 45.225 ;
         RECT 156.435 34.075 157.285 34.925 ;
         RECT 134.300 29.350 135.750 30.150 ;
@@ -1590,9 +1590,9 @@ MACRO tt_um_twin_tee_opamp_osc
         RECT 128.250 51.530 145.110 66.930 ;
         RECT 146.375 66.895 147.525 67.985 ;
         RECT 146.400 66.890 147.500 66.895 ;
-        RECT 144.105 50.780 145.015 50.805 ;
-        RECT 144.100 49.860 145.790 50.780 ;
-        RECT 144.105 49.835 145.015 49.860 ;
+        RECT 144.860 50.055 145.780 50.060 ;
+        RECT 144.835 49.145 145.805 50.055 ;
+        RECT 144.860 48.570 145.780 49.145 ;
         RECT 134.200 30.165 141.150 30.200 ;
         RECT 134.200 29.975 141.715 30.165 ;
         RECT 134.200 29.525 141.750 29.975 ;
@@ -1624,7 +1624,7 @@ MACRO tt_um_twin_tee_opamp_osc
         RECT 107.070 63.170 107.790 63.890 ;
         RECT 125.730 51.470 126.050 66.590 ;
         RECT 144.690 51.670 145.010 66.790 ;
-        RECT 144.105 49.865 145.015 50.775 ;
+        RECT 144.865 49.145 145.775 50.055 ;
         RECT 156.415 7.755 157.305 8.645 ;
       LAYER met4 ;
         RECT 3.990 223.800 4.290 224.760 ;
@@ -1685,7 +1685,8 @@ MACRO tt_um_twin_tee_opamp_osc
         RECT 126.690 50.780 127.610 61.400 ;
         RECT 128.645 51.925 143.255 61.400 ;
         RECT 144.610 51.590 145.090 62.050 ;
-        RECT 126.690 49.860 145.020 50.780 ;
+        RECT 126.690 49.860 145.780 50.780 ;
+        RECT 144.860 49.140 145.780 49.860 ;
         RECT 2.500 43.750 29.750 45.250 ;
         RECT 156.410 1.000 157.310 8.650 ;
   END