Shmoo plot

Python Code

"""Chip Test — Shmoo plot (pass/fail in V×F space, computed)."""


import numpy as np
import plotly.graph_objects as go


def generate():
    V = np.linspace(0.6, 1.2, 60)   # voltage (V)
    F = np.linspace(0.1, 2.0, 80)   # frequency (GHz)

    # Fmax(V): max operating frequency given supply voltage
    Fmax = 2.0 * (1 - np.exp(-5 * (V - 0.7)))
    Fmax = np.clip(Fmax, 0, None)

    # Build pass/fail matrix
    pass_matrix = np.zeros((len(V), len(F)), dtype=int)
    for i, v in enumerate(V):
        if v >= 0.7:
            for j, f in enumerate(F):
                if f <= Fmax[i]:
                    pass_matrix[i, j] = 1

    print(f"  pass cells: {pass_matrix.sum()} / {pass_matrix.size}")

    colorscale = [
        [0.0,  "#DA5597"],
        [0.49, "#DA5597"],   # fail — PINK (sharp boundary)
        [0.51, "#55B685"],
        [1.0,  "#55B685"],   # pass — GREEN
    ]

    fig = go.Figure(go.Heatmap(
        x=F,
        y=V,
        z=pass_matrix,
        colorscale=colorscale,
        zmin=0,
        zmax=1,
        colorbar=dict(
            tickvals=[0.25, 0.75],
            ticktext=["FAIL", "PASS"],
            thickness=16,
            len=0.5,
        ),
        hovertemplate="Freq: %{x:.2f} GHz<br>Volt: %{y:.3f} V<br>%{z}<extra></extra>",
    ))

    # Overlay Fmax curve
    fig.add_trace(go.Scatter(
        x=Fmax,
        y=V,
        mode="lines",
        line=dict(color="white", width=2.5, dash="dash"),
        name="Fmax boundary",
        hovertemplate="V=%{y:.3f} V → Fmax=%{x:.2f} GHz<extra></extra>",
    ))

    fig.update_layout(
        xaxis=dict(title="Frequency (GHz)"),
        yaxis=dict(title="Voltage (V)"),
        legend=dict(x=0.02, y=0.98, bgcolor="rgba(0,0,0,0.4)", font=dict(color="white")),
        margin=dict(t=20, b=60, l=60, r=80),
    )

    return fig


if __name__ == "__main__":
    generate()

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