SPICE simulation & analog design
Size components and simulate until specs are met.
20 project-authored proposals · taxonomy v1.1 · 0 new benchmark runs. Verifiers and partial-credit rules below are designs, not executed results.
- Typical applications
- LTspice · ngspice · Cadence Spectre
- Class GUI-need label
HY· Hybrid
Task proposals · 20
Expand to inspect the complete original wording and proposed checks. Original proposal text remains English in both interfaces.
R07.03.01.02-T01 LTspice: non-inverting amplifier with 20 dB gain and 100 kHz bandwidth
Original instruction
In LTspice, draw a non-inverting amplifier with the LT1007 model (±15 V), choose E96 resistors for 20 dB ±0.5 dB gain, run an AC sweep 10 Hz–10 MHz, and add .meas statements for gain at 1 kHz and −3 dB bandwidth (must be ≥ 100 kHz). Save output/amp.asc.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 2 / 5
Proposed verifier
Grader runs LTspice batch on the .asc and parses .meas: gain 19.5–20.5 dB, BW ≥ 100 kHz; resistors are E96 values; schematic uses LT1007 (not an ideal op-amp).
Proposed partial credit
30% circuit correct; 40% gain; 30% bandwidth.
R07.03.01.02-T02 LTspice: Sallen-Key low-pass with fc 1 kHz and Q 0.707
Original instruction
Design a unity-gain Sallen-Key low-pass in LTspice with an LT1678, fc = 1 kHz ±5% and Q = 0.707 ±5%, using E24 capacitors and E96 resistors. Add .meas for fc and peaking; save output/sk.asc.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Batch sim: fc and Q (from fitted response) within ±5%; component values in E-series; topology is Sallen-Key (netlist pattern check).
Proposed partial credit
20% topology; 40% fc; 40% Q.
R07.03.01.02-T03 LTspice: buck output capacitance for < 30 mV ripple at 10 A
Original instruction
Open input/buck_ltm4648.asc (5 V in, 1.5 V out). Choose output capacitance (count of 100 µF ceramics, with their ESR model) so peak-to-peak ripple at a 10 A load is < 30 mV after startup, with 1 ms transient including startup. Save output/buck.asc.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & formsvis· Visual judgment- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Batch transient: ripple measured 0.8–1.0 ms < 30 mV p-p; Vout 1.5 V ±1%; cap count minimal within +1 of reference optimum (bonus credit).
Proposed partial credit
30% sim runs with load; 50% ripple spec; 20% minimal capacitance.
R07.03.01.02-T04 LTspice: Monte Carlo spread of a filter's cutoff
Original instruction
For input/rc_filter.asc (3rd-order passive LPF), apply 1% resistor and 5% capacitor tolerances with mc() functions, run 200 Monte Carlo runs, and report the 3σ spread of the −3 dB frequency to output/mc.json.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Schematic uses mc() with correct tolerances on every R/C; .step param run 1 200; reported mean and 3σ within 5% of grader's own 2000-run estimate.
Proposed partial credit
40% tolerance setup; 20% 200 runs; 40% statistics.
R07.03.01.02-T05 LTspice: class-AB power amplifier under 0.1% THD at 10 W
Original instruction
Design a discrete class-AB amplifier in LTspice (±25 V rails, input/models.lib transistors) delivering 10 W into 8 Ω at 1 kHz with THD < 0.1% (.four), quiescent current 20–60 mA per output device, and stable (no oscillation with 100 pF at the output).
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & formsvis· Visual judgment- Work product
WP06· Code/engineering- Conditions
long· Long-horizon- Proposed difficulty
- 5 / 5
Proposed verifier
Batch runs: .four THD < 0.1% at 12.65 V peak output; quiescent currents in range from .op; transient with 100 pF load shows no oscillation (no spectral content > −60 dBc above 100 kHz).
Proposed partial credit
30% 10 W achieved; 35% THD; 15% bias; 20% stability.
R07.03.01.02-T06 Xschem + ngspice: sky130 five-transistor OTA sizing
Original instruction
In Xschem with the sky130 PDK, size a 5-transistor OTA (1.8 V, 10 µA tail) so DC gain > 40 dB and GBW > 10 MHz with 1 pF load; add a testbench with AC analysis and save results via .control/meas.
- Platforms
lin· Linux- Applications
- Xschem · ngspice · sky130 PDK
- Interfaces
desk· Desktop GUIterm· Terminal- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & dropcode· Code & commands- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 4 / 5
Proposed verifier
Grader netlists the schematic with xschem CLI and runs ngspice: gain and GBW specs; transistor W/L on grid and ≥ min rules; tail current 10 µA ±10%.
Proposed partial credit
30% testbench runs; 35% gain; 35% GBW.
R07.03.01.02-T07 Virtuoso ADE: bandgap reference tempco under 20 ppm/°C
Original instruction
In Cadence Virtuoso with the provided 180 nm PDK, complete the bandgap in input/bgr_lib (resistor ratios and trim) so VREF ≈ 1.2 V with temperature coefficient < 20 ppm/°C over −40…125 °C and PSRR > 50 dB at 1 kHz, verified in ADE Assembler.
- Platforms
lin· Linux- Applications
- Cadence Virtuoso · Spectre
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & formsvis· Visual judgment- Work product
WP06· Code/engineering- Conditions
licensed· Licensed pro applong· Long-horizon- Proposed difficulty
- 5 / 5
Proposed verifier
Grader runs the saved ADE state headless (ocean): box-method tempco < 20 ppm/°C, VREF 1.18–1.22 V, PSRR > 50 dB at 1 kHz; corners TT only.
Proposed partial credit
30% VREF; 40% tempco; 30% PSRR.
R07.03.01.02-T08 LTspice: LDO loop stability with Middlebrook injection
Original instruction
For input/ldo.asc (discrete LDO, 1–10 µF output caps with 5–500 mΩ ESR), insert a Middlebrook voltage injection to measure loop gain and choose the compensation capacitor so phase margin > 45° across the ESR/C corners (.step). Report worst-case PM.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 4 / 5
Proposed verifier
Batch sim: injection source in feedback path; stepped corners; grader computes PM from the loop-gain trace at each corner: min PM > 45°; reported value ±3°.
Proposed partial credit
30% injection setup; 20% corner stepping; 50% worst-case PM met.
R07.03.01.02-T09 LTspice: RCD snubber limiting flyback drain overshoot
Original instruction
In input/flyback.asc (65 kHz, 400 V bus), design an RCD clamp so the MOSFET drain peak stays < 600 V at full load while clamp dissipation is minimised (< 1.5 W). Report component values and measured peak.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & formsvis· Visual judgment- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 4 / 5
Proposed verifier
Batch transient steady-state: Vds peak < 600 V; clamp resistor average power < 1.5 W (.meas); values reported match the schematic.
Proposed partial credit
50% peak limit; 30% dissipation limit; 20% report consistency.
R07.03.01.02-T10 Qucs-S: 10.7 MHz LC bandpass S-parameters
Original instruction
In Qucs-S, design a coupled-resonator LC bandpass at 10.7 MHz with 300 kHz −3 dB bandwidth in 50 Ω, simulate S-parameters, and save the schematic and a dataset showing S21 and S11.
- Platforms
win· Windowsmac· macOSlin· Linux- Applications
- Qucs-S · ngspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Grader runs the schematic: centre frequency ±1%, BW ±10%, S11 < −15 dB at centre, insertion loss < 2 dB.
Proposed partial credit
30% centre; 30% bandwidth; 20% S11; 20% IL.
R07.03.01.02-T11 LTspice: NE555 astable at 1 kHz and 25% duty
Original instruction
Draw a 555 astable in LTspice (NE555 model, 5 V) producing 1 kHz ±3% with 25% ±2% duty (use a diode-steered network), and add .meas for frequency and duty. Save output/astable.asc.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 2 / 5
Proposed verifier
Batch transient after 10 ms: frequency and duty from .meas and grader's own edge detection within tolerance.
Proposed partial credit
20% circuit; 40% frequency; 40% duty.
R07.03.01.02-T12 ngspice: fit diode model parameters to measured I-V data
Original instruction
Using KiCad's simulator front-end (ngspice), fit IS, N and RS of a diode .model so the simulated DC sweep matches input/diode_iv.csv (1 nA–100 mA) with RMS log-current error < 5%. Save the model and the overlay plot.
- Platforms
win· Windowsmac· macOSlin· Linux- Applications
- KiCad Simulator · ngspice
- Interfaces
desk· Desktop GUIterm· Terminal- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & formscode· Code & commands- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 4 / 5
Proposed verifier
Grader simulates the saved .model across the CSV points: RMS log error < 5% (scaled credit to 15%); parameters physically plausible (N 1–2.5).
Proposed partial credit
20% model saved; 70% fit quality; 10% plot.
R07.03.01.02-T13 PSpice: worst-case analysis of a voltage divider reference
Original instruction
In OrCAD PSpice, set tolerances on input/vref.dsn (resistors 0.5%, reference 1%), run a Worst-Case/Sensitivity analysis for output voltage and report the worst-case high/low and the most sensitive component.
- Platforms
win· Windows- Applications
- PSpice · OrCAD Capture
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & forms- Work product
WP06· Code/engineering- Conditions
licensed· Licensed pro app- Proposed difficulty
- 3 / 5
Proposed verifier
Simulation profile has worst-case analysis with tolerance properties; reported bounds within 0.5 mV of grader's computation; component ID exact.
Proposed partial credit
30% tolerance setup; 50% bounds; 20% sensitivity.
R07.03.01.02-T14 LTspice: photodiode transimpedance amp at 1 MHz with PM > 60°
Original instruction
Design a TIA in LTspice for a 10 pF photodiode (input/pd.lib) with 100 kΩ gain using an ADA4817, choosing the feedback capacitor for −3 dB ≥ 1 MHz and phase margin > 60° (noise-gain analysis). Verify with AC and a 1 µA step.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & formsvis· Visual judgment- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 4 / 5
Proposed verifier
Batch: transimpedance 100 dBΩ ±0.5, BW ≥ 1 MHz, step overshoot < 10% (proxy for PM > 60°) and grader's loop-gain PM > 60°.
Proposed partial credit
20% gain; 40% bandwidth; 40% stability.
R07.03.01.02-T15 Xschem: 11-stage ring oscillator tuned to 100 MHz
Original instruction
In Xschem (sky130), build an 11-stage current-starved ring oscillator and size the starving transistors so it oscillates at 100 MHz ±5% at Vctrl = 0.9 V; add a transient testbench measuring frequency.
- Platforms
lin· Linux- Applications
- Xschem · ngspice · sky130 PDK
- Interfaces
desk· Desktop GUIterm· Terminal- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & dropcode· Code & commands- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Grader netlists and runs ngspice: frequency within ±5%; 11 stages; oscillation starts within 50 ns.
Proposed partial credit
30% topology; 50% frequency; 20% startup.
R07.03.01.02-T16 LTspice: import a vendor MOSFET model and estimate switching loss
Original instruction
Import the vendor model input/IPB017N10N5.lib into LTspice, create/associate a symbol, build a double-pulse test (48 V, 50 A, 10 Ω gate), and measure turn-on and turn-off energy with .meas integrals.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clickdrag· Drag & droptype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Batch: subcircuit used via .lib/.include with correct pin mapping (gate/drain/source order check); Eon/Eoff within 10% of reference.
Proposed partial credit
30% model import and pin mapping; 20% double-pulse setup; 50% energies.
R07.03.01.02-T17 Virtuoso ADE: 2.4 GHz LNA S11 and noise figure
Original instruction
Complete the inductively degenerated LNA in input/lna_lib (choose Lg, Ls and bias) so S11 < −10 dB across 2.4–2.48 GHz, NF < 2 dB and gain > 15 dB, verified with SP and noise analyses in ADE.
- Platforms
lin· Linux- Applications
- Cadence Virtuoso · Spectre RF
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & formsvis· Visual judgment- Work product
WP06· Code/engineering- Conditions
licensed· Licensed pro applong· Long-horizon- Proposed difficulty
- 5 / 5
Proposed verifier
Grader runs saved ADE state headless: S11, NF, S21 across band; component values within PDK ranges.
Proposed partial credit
35% S11; 35% NF; 30% gain.
R07.03.01.02-T18 LTspice: Li-ion charger CC/CV transition check
Original instruction
Simulate input/charger_lt4121.asc with the battery behavioural model in input/batt.lib from 3.0 V and report the CC current, the time of CC→CV transition and the termination time; adjust the PROG resistor for 1.0 A ±5% charge current.
- Platforms
win· Windowsmac· macOS- Applications
- LTspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & formsvis· Visual judgment- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Batch transient: CC current 0.95–1.05 A; reported transition and termination times within 3% of grader's measurement from the same run.
Proposed partial credit
40% PROG resistor; 30% transition time; 30% termination time.
R07.03.01.02-T19 ngspice: preamp input-referred noise below 5 nV/√Hz
Original instruction
Using KiCad's simulator with ngspice, adjust the input-stage collector current and source resistors of input/mic_preamp.kicad_sch so input-referred noise at 1 kHz is < 5 nV/√Hz while gain stays 40 dB ±0.5 dB; run .noise and save the plot.
- Platforms
win· Windowsmac· macOSlin· Linux- Applications
- KiCad Simulator · ngspice
- Interfaces
desk· Desktop GUI- GUI need · task setting
HY· Hybrid- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
click· Point & clicktype· Text & forms- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 3 / 5
Proposed verifier
Grader runs .noise and .ac from the schematic: inoise at 1 kHz < 5 nV/√Hz; gain within tolerance.
Proposed partial credit
60% noise spec; 40% gain held.
R07.03.01.02-T20 Control pair of T02: Sallen-Key design as an ngspice netlist
Original instruction
Control pair of T02. Without a schematic editor, write output/sk.cir as an ngspice netlist with the same specs and E-series constraints and run it with ngspice -b, printing fc and Q via .meas.
- Platforms
lin· Linuxmac· macOS- Applications
- ngspice
- Interfaces
term· Terminal- GUI need · task setting
CL· CLI-sufficient- GUI need · ordinary access
CL· CLI-sufficient- Interaction primitives
code· Code & commands- Work product
WP06· Code/engineering- Conditions
- None declared
- Proposed difficulty
- 2 / 5
Proposed verifier
Same fc/Q tolerances and E-series checks as T02; reported as the CLI baseline.
Proposed partial credit
20% topology; 40% fc; 40% Q.
Mapped research references
Existing benchmark-to-class links from the research catalog. They are not record-level annotations, executions or product endorsements.