The Project

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A fantastic project that just might turn your world upside down, push you to re-evaluate your life choices, and stare briefly into the existential void… all while being deeply enjoyable and engaging! - Domen, AIC2025

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The goal of the project is for you to experience a full mixed signal integrated circuit design, with the option of tapeout!

In 2025, two groups reached a tapeout of their design http://analogicus.com/jnw-tt-2025/ on the https://tinytapeout.com/chips/ttsky25a/ Tiny Tapeout shuttle.

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The challenge

Design a temperature sensor

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Systems-on-chip have complex regulator systems

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Leakage current varies orders of magnitude over temperature

I_{leak} = I_0 e^{-V_{th}/n V_T} \left(1 - e^{-V_{ds}/V_T}\right)

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Assume 1 pA at 25 C, and 1 nA at 125 C, per logic cell
Assume 100 million logic cells
Leakage at 25 C => 100 uA
Leakage at 125 C => 100 mA !!!

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Why we would like to know the temperature on die

Assume we use 1 % of the load current for the regulator
At 25 C => 1 uA for LDO
At 125 C => 1 mA for LDO

It's insanely difficult to design a regulator that is efficient across the full range of leakage currents at any temperature.

It would be good if we could know temperature.

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How to measure temperature?

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The Project

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Key	Parameter	Value	Unit	Description
Area	Area	< 15000	um^2	Must fit in 161 um x 111 um tiny tapeout 1x1 block, which is 17871 um^2
Tc	Conversion time	< 30	us	Analog should only be active for one 32768 Hz period
Ts	Sample period	100	ms	One conversion every 100 ms, so 10 samples per second
Ileak	Leakage current	< 1	nA	Typical temperature (25 C)
Iact	Active current	< 100	uA	Typical temperature (25 C)
Iavg	Average current	< 50	nA	Active current x conversion time/sample rate + leakage current. Typical temperature (25 C)
Kerrone	Accuracy 0 - 70C	+-10	C	One temperature (25C) calibration
Kerrtwo	Accuracy 0 - 70C	+-5	C	Two temperature (25C, 85C) calibration

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Figure of Merit

A figure of merit allows us to compare circuits with different performance specifications, and try to answer the question. Which one is better?

The figure of merit for our temperature sensor will be

FOM = \left(\frac{T_{c}}{T_s}I_{act} + I_{leak}\right) K_{errtwo} \text{ [AK]}

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Grade

Week	Deadline	Milestone	Task	Condition for more than 0 points	Possible Points
4	2026-01-23	M0	Complete tutorial	Link on blackboard	5
7	2026-02-13	M1	Design a circuit that can convert a temperature into a current and voltage	Description of the circuit on github docs	5
10	2026-03-06	M2	Design a circuit that can convert a temperature into a frequency	Description of the circuit on github docs. Demonstrate that it works	10
13	2026-03-27	M3	A verilog testbench that can convert a frequency into a digital value	Description of the testbench on github docs. Demonstrate that it works	10
16	2026-04-17	M4	Layout of your circuit	DRC/LVS/GDS passing on github	20
18	2026-05-01	M5	Individual report	Uploaded to Inspera	48
?		M6	Tapeout	None	0
		Coolness	Extra points that I may choose to award		10
		Total			108

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Milestone 0: The tutorial

Goal: force you to install the tools, and get you started.

Follow Sky130nm Tutorial

Delivery: Submit link to your github repository on blackboard

For example, my repository: LELO_EX_SKY130A

The exercise will teach you the skills you need to do the project

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Milestone 1: The bandgap

Goal: Create a circuit that can transform a temperature on the integrated circuit to a current proportional to temperature (PTAT), and a voltage complementary to temperature (CTAT).

Delivery: Link to your github repository with a description of how the bandgap works.

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Milestone 2: The oscillator

Goal: Use the PTAT current, and the CTAT voltage an create a oscillator.

Delivery Link to your github repository with description on how your oscillator works. There should be proof on how it works.

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Milestone 3: The measurement

Goal: Measure the frequency of the oscillator.

Delivery: Link to your github repository where you describe how you measure the frequency of the oscillator.

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Milestone 4 (Optional): The physical design

Goal: Do the physical layout of your oscillator, and prove that it still works with the layout parasitics.

Delivery: Link to your github repository with passing GDS, DRC, LVS actions.

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Milestone 5: The Report

Goal: Write a report

Delivery: A PDF copy of the report in Inspera. You'll all write an individual report. The report shall be in the IEEE template.

See further details in https://analogicus.com/aic2026/how_to_write_a_project_report

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Milestone 6 (Optional): The Tapeout

Target TTSKY26b tapeout (June 2026) on https://tinytapeout.com/chips/

Those students that follow the course at NTNU will be able to tapeout if the design is complete. I've gotten Nordic Semiconductor to sponsor the tapeout for 2026.

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Thanks!

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Summary

The project is the course: design a block in an open PDK, simulate it over corners, and document the evidence
Start from the template repositories and the cic flow on day one - infrastructure debt compounds
Work like an engineer: git for everything, scripts over clicks, claims backed by simulation
The report is the deliverable; the next chapter's writing guide is not optional reading

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Would you like to know more?

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