Update project tt_um_mos_bandgap (mattvenn/tt07-mos-bandgap)

projects/tt_um_mos_bandgap/commit_id.json

@@ -1,8 +1,8 @@
 {
   "app": "custom_gds action",
   "repo": "https://github.com/mattvenn/tt07-mos-bandgap",
-  "commit": "f3441791246acee17733fb3114fdcadcb474d595",
-  "workflow_url": "https://github.com/mattvenn/tt07-mos-bandgap/actions/runs/9301748925",
+  "commit": "f6405110c39f151368244388047015b4781391d3",
+  "workflow_url": "https://github.com/mattvenn/tt07-mos-bandgap/actions/runs/9320173499",
   "sort_id": 1716719574645,
   "analog": true
 }

projects/tt_um_mos_bandgap/docs/info.md

@@ -9,30 +9,47 @@ You can also include images in this folder and reference them in the markdown. E
 
 ## How it works
 
-[Read the paper here](http://www.av.it.pt/conftele2009/Papers/16.pdf)
+[Read the paper here](http://www.av.it.pt/conftele2009/Papers/16.pdf) and see the DTMOS variant below.
 
 ## Circuit
 
 ![bandgap circuit](bandgap_circuit.png)
 
+DTMOS variant connects the lower PMOS body to VSS instead of VDD.
+
 ![opamp buffer](bandgap_opamp.png)  
 
 ## Simulation
 
-Simulated output is 0.714 to 0.716v across 10 to 120 degrees C.
+## MOS
+
+* Simulated output is 0.714 to 0.716v across 10 to 120 degrees C.
+* Simulated output is 0.6 to 0.8v across 1.6 to 2v VDD.
+
+![sim](vdd_and_temp_sweep.png)
+
+## DTMOS
 
-Simulated output is 0.6 to 0.8v across 1.6 to 2v VDD.
+* Simulated output is 0.515 to 0.510v across 10 to 120 degrees C.
+* Simulated output is 0.3 to 0.6v across 1.6 to 2v VDD.
 
-![output](vdd_and_temp_sweep.png)
+![sim](dtmos_vdd_and_temp_sweep.png)
 
 ## How to test
 
+### MOS
+
 Connect a multimeter to analog output 0. It should measure around 0.7v and remain constant with temperature.
 
+### DTMOS
+
+Connect a multimeter to analog output 0. It should measure around 0.5v and remain constant with temperature.
+
 ## External hardware
 
 Multimeter, hot air gun to heat the chip
 
 ## References
 
 * [A sky130 reference bandgap with results](https://github.com/johnkustin/bandgapReferenceCircuit)
+* [DTMOS varient](https://www.researchgate.net/publication/4157633_Low-power_bandgap_references_featuring_DTMOSTs)

projects/tt_um_mos_bandgap/info.yaml

@@ -11,7 +11,7 @@ project:
   tiles: "1x2"          # Valid values: 1x1 (digital only), 1x2, 2x2, 3x2, 4x2, 6x2 or 8x2
 
   # How many analog pins does your project use?
-  analog_pins: 1        # Valid values: 0 to 6
+  analog_pins: 2        # Valid values: 0 to 6
 
   # Your top module name must start with "tt_um_". Make it unique by including your github username:
   top_module:  "tt_um_mos_bandgap"
@@ -53,8 +53,8 @@ pinout:
   uio[7]: ""
 
   # Analog pins - make sure to also set "analog_pins" above, else the pins won't be connected
-  ua[0]: "vref"
-  ua[1]: ""
+  ua[0]: "bandgap"
+  ua[1]: "bandgap_dtmos"
   ua[2]: ""
   ua[3]: ""
   ua[4]: ""