Chaya·EduEDU.CHAYA.DEV
Fall 2026 · Section 001 · Class #4393 · 3 credits
ENGR 255

Physical Foundations of Digital Engineering

This course addresses the basic principles governing the physical realization of computing systems and their relationship to performance, energy, and robustness. It begins with the question of what it physically takes to represent and reliably change a single bit, and builds up through CMOS devices, interconnect, and timing to complete digital systems. The physical limits of CMOS are examined, and analog, quantum, and biological computing are introduced. The treatment is practical and model-driven: students build and validate computational models of the devices and circuits under study rather than working from closed-form derivations alone.

Mon & Wed 6:00 – 7:50 PM Online — all sessions live on Google Meet Room of record: Pratt 520

Dial in: +1 631-769-5311 · PIN 233 399 950# · more numbers

Lecture notes

Session Notes

Posted before the session they're used in and kept available all term. Each set is a self-contained page — read it, work the examples, and bring questions.

Fifteen weeks

Weekly Schedule

The schedule is aligned to the LIU Brooklyn academic calendar; any session affected by a University holiday or closure is adjusted and announced in class and on Brightspace. The current week is highlighted.

WeekSessionsTopicMaterialsTo do
WK 1 S1 · Sep 2 Course overview. From physics to computation: the digital abstraction Notes 01
  • Set up Python and simulation toolchain
  • Set up Git and GitHub
  • Join the course repository
WK 2 S2 · Sep 9 Representing a bit: distinguishability, state change, and the barrier model◦ Sep 7 — no class (Labor Day) Notes 02
  • Review Notes 01–02
  • Project 1 specification released
WK 3 S3–S4 · Sep 14, Sep 16 Energy, entropy, and thermal noise. The physical cost of reliability Notes 03
  • Review Notes 03
  • Project 1 work begins
WK 4 S5–S6 · Sep 21, Sep 23 Semiconductor physics essentials for the digital engineer Notes 04 · soon
  • Review Notes 04
  • Project 1 in progress
WK 5 S7–S8 · Sep 28, Sep 30 MOSFET device physics: structure, operating regions, and models
Project 1 due
Notes 05 · soon
  • Review Notes 05
  • Project 1 due
WK 6 S9–S10 · Oct 5, Oct 7 Switches as computing devices. CMOS inverter and static logic families Notes 06 · soon
  • Review Notes 06
  • Project 2 specification released
WK 7 S11–S12 · Oct 12, Oct 14 Interconnected switches: combinational logic and physical composition Notes 07 · soon
  • Review Notes 07
  • Project 2 in progress
WK 8 S13–S14 · Oct 19, Oct 21 RC circuit analysis and delay modeling of gates and loads
Project 2 due
Notes 08 · soon
  • Review Notes 08
  • Project 2 due
WK 9 S15–S16 · Oct 26, Oct 28 Wires: signal propagation, transmission-line behavior, and communication cost Notes 09 · soon
  • Review Notes 09
  • Project 3 specification released
WK 10 S17–S18 · Nov 2, Nov 4 Performance: critical path, delay budgets, and speed analysis Notes 10 · soon
  • Review Notes 10
  • Project 3 in progress
WK 11 S19–S20 · Nov 9, Nov 11 Energy: dynamic and static power, and the energy-delay trade-off Notes 11 · soon
  • Review Notes 11
  • Project 3 in progress
WK 12 S21–S22 · Nov 16, Nov 18 Robustness: noise margins, thermal and coupling noise, and error
Project 3 due
Notes 12 · soon
  • Review Notes 12
  • Project 3 due
  • Project 4 specification released
WK 13 S23–S24 · Nov 23, Nov 25 Sequential logic, clocking, timing closure, and metastability. FSM and Turing models
Capstone proposal due
Notes 13 · soon
  • Review Notes 13
  • Capstone proposal due
WK 14 S25–S26 · Nov 30, Dec 2 Memory, input/output, and the physical limits of CMOS. CMOS analog computing Notes 14 · soon
  • Review Notes 14
  • Capstone in progress
WK 15 S27–S28 · Dec 7, Dec 9 Alternative models: quantum and biological computing. Capstone presentations Notes 15 · soon
  • Review Notes 15
  • Capstone presentations
  • Final report and model submission
FINALS Dec 14 – 21 Final capstone deliverables due. No final examination.
No examinations

Projects & Grading

This course is graded entirely on four hands-on projects — there are no exams. Specifications and rubrics are released at least two weeks before each due date. Every project is submitted as a Git repository plus a written report; late work is reduced by 10% per calendar day.

Project 125%

Bit Representation and Noise Analysis

Build a computational model of a bit held by an energy barrier, and determine the minimum barrier height and switching energy required for a specified error rate at a specified temperature. The written component relates the model to thermal noise limits and to the observed behavior of real devices.

Project 225%

CMOS Logic: Speed and Energy

Design a small CMOS logic block, simulate it, and characterize its propagation delay, dynamic and static power, and noise margins across a range of supply voltages and loads. Deliverables include the simulation files and an energy-delay trade-off analysis.

Project 325%

Interconnect, Timing, and Signal Integrity

Model the RC behavior of the interconnect in a small datapath, determine the maximum clock frequency the physical layer permits, and analyze coupling noise between adjacent lines. The written component identifies which physical effect binds the design and why.

Project 425%

Capstone: Beyond CMOS

Select a non-CMOS computing technology — analog, quantum, biological, or another approved alternative — and produce a design study applying speed, energy, and reliability analysis to a specific computational task, with a defensible comparison against a CMOS baseline. Model, technical report, and a live presentation.

Grading rubric — how every project is assessed

Every project is graded on the same four criteria. Each project rubric is released with its specification.

CriterionWeightWhat is assessed
Correctness and completeness35%The artifact does what the specification requires, and the required cases are handled.
Implementation quality20%Structure, readability, and evidence of testing. Commit history shows sustained individual work.
Analysis and written report25%The report explains the design, justifies the decisions, and reports results honestly, including what did not work.
Demonstration and defense20%The student can run the artifact live and answer questions about any part of it.
Grading scale
LetterRange %GPA
A93–1004.00
A-90–923.67
B+87–893.33
B83–863.00
B-80–822.67
C+77–792.33
C73–762.00
C-68–721.67
D60–671.00
F< 600.00
Expected time commitment (160 h total)
Synchronous class sessions51 h
Review of posted notes30 h
Project 1 — Bit Representation and Noise17 h
Project 2 — CMOS Logic: Speed and Energy20 h
Project 3 — Interconnect and Timing20 h
Project 4 — Capstone and presentation22 h
Total160 h
The fine print

Course Info & Policies

Prerequisites

College-level physics and mathematics through calculus, and programming proficiency in a language of your choice, or permission of the instructor.

Software & tools — all free

  • Python 3.11 or later with NumPy, SciPy, and Matplotlib (for modeling and analysis)
  • ngspice or LTspice (circuit simulation)
  • Logisim Evolution (logic-level design and exploration)
  • Git and a personal GitHub account
  • Google Meet, for all synchronous class sessions

What you'll be able to do

  1. Perform speed and energy analysis of devices and circuits used as digital logic elements.
  2. Derive the computational power of both finite (FSM) and infinite (Turing) models of computation.
  3. Derive and compute noise limits (thermal, coupling, and other) in digital devices and interconnect.
  4. Apply speed, energy, and reliability properties of CMOS to the design of simple CMOS digital circuits.
  5. Apply speed, energy, and reliability properties to the design of at least one non-CMOS technology.
  6. Communicate a physical-design analysis in written form and in a technical presentation.
Live sessions & attendance

All class sessions are held live on Google Meet at the scheduled times. Students are expected to attend, to have their development environment running, and to be able to share their screen when demonstrating work. Every student presents current work and takes part in critique at each meeting.

Communication

Modes of communication are Brightspace (lms.liu.edu) and email; expect a reply within 24 hours. Virtual office hours are held by appointment — email the instructor to schedule.

Materials & this site

All course notes, examples, and project specifications are distributed through the course repository and this site. Students are responsible for reviewing the current version before each session.

Submission & late work

Every project is submitted through Brightspace as a link to the student's Git repository, together with the written report. Commit history is part of the evidence of individual work. Late work is reduced by 10% per calendar day. Extensions are granted only for a documented medical or family emergency, requested before the deadline by email.

Individual work & AI use

Projects are individual work unless a specification explicitly designates a team deliverable. Discussing approaches is fine, but submitted code, models, and writing must be your own. Generative AI tools may be used as a learning aid and are treated like any other reference: any AI-assisted portion of a submission must be disclosed in the project report, and you must be able to explain and defend every line of what you submit.

Recording

Recording of class sessions by students is not permitted without the instructor's prior written consent.

Accommodations

Students with a documented disability/impairment who require reasonable accommodations should provide an Accommodation Letter from Student Support Services (Sloan Building, 1st Floor · 718-488-1044 · studentsupportservices@brooklyn.liu.edu · Mon–Fri 9am–5pm).

Technical issues

For issues with Brightspace, LIU email, Google Meet, or campus network access, contact IT: It@liu.edu · 718-488-3300 (Mon–Fri 9am–5pm).

← All courses