From 2758ecb94a746f3567c607ae5096a2f580d3ccd6 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Sun, 7 Dec 2025 10:31:19 +0200
Subject: [PATCH] feat: Use proper MOSFET model for SPICE conversion

---
 lib/circuitJsonToSpice.ts               | 33 +++++++++++--------------
 tests/examples/boost-converter.test.tsx |  4 +--
 tests/examples/buck-converter.test.tsx  |  4 +--
 3 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/lib/circuitJsonToSpice.ts b/lib/circuitJsonToSpice.ts
index 0ca6bef..0f4b42c 100644
--- a/lib/circuitJsonToSpice.ts
+++ b/lib/circuitJsonToSpice.ts
@@ -6,6 +6,7 @@ import { VoltageSourceCommand } from "./spice-commands/VoltageSourceCommand"
 import { BJTCommand } from "./spice-commands/BJTCommand"
 import { DiodeCommand } from "./spice-commands/DiodeCommand"
 import { InductorCommand } from "./spice-commands/InductorCommand"
+import { MOSFETCommand } from "./spice-commands/MOSFETCommand"
 import { VoltageControlledSwitchCommand } from "./spice-commands/VoltageControlledSwitchCommand"
 import type {
   AnyCircuitElement,
@@ -361,33 +362,29 @@ export function circuitJsonToSpice(
             const sourceNode =
               nodeMap.get(sourcePort?.source_port_id ?? "") || "0"
 
-            const channel_type = component.channel_type
+            // For 3-pin MOSFETs, substrate is typically connected to source
+            const substrateNode = sourceNode
 
-            let positiveControl = gateNode
-            let negativeControl = sourceNode
-            if (channel_type === "p") {
-              positiveControl = sourceNode
-              negativeControl = gateNode
-            }
+            const channel_type = (component as any).channel_type ?? "n"
+            const mosfet_mode = (component as any).mosfet_mode ?? "enhancement"
+
+            const modelType = `${channel_type.toUpperCase()}MOS`
+            const modelName = `${modelType}_${mosfet_mode.toUpperCase()}`
 
-            const modelName = "ENH_SW"
             if (!netlist.models.has(modelName)) {
-              netlist.models.set(
-                modelName,
-                `.MODEL ${modelName} SW(Ron=0.1 Roff=1e9 Vt=2.5 Vh=0.1)`,
-              )
+              netlist.models.set(modelName, `.MODEL ${modelName} ${modelType}`)
             }
 
-            const switchCmd = new VoltageControlledSwitchCommand({
+            const mosfetCmd = new MOSFETCommand({
               name: component.name,
-              positiveNode: drainNode,
-              negativeNode: sourceNode,
-              positiveControl,
-              negativeControl,
+              drain: drainNode,
+              gate: gateNode,
+              source: sourceNode,
+              substrate: substrateNode,
               model: modelName,
             })
 
-            spiceComponent = new SpiceComponent(component.name, switchCmd, [
+            spiceComponent = new SpiceComponent(component.name, mosfetCmd, [
               drainNode,
               gateNode,
               sourceNode,
diff --git a/tests/examples/boost-converter.test.tsx b/tests/examples/boost-converter.test.tsx
index f4c2259..93d79f1 100644
--- a/tests/examples/boost-converter.test.tsx
+++ b/tests/examples/boost-converter.test.tsx
@@ -17,12 +17,12 @@ test(
     expect(spiceString).toMatchInlineSnapshot(`
       "* Circuit JSON to SPICE Netlist
       .MODEL D D
-      .MODEL ENH_SW SW(Ron=0.1 Roff=1e9 Vt=2.5 Vh=0.1)
+      .MODEL NMOS_ENHANCEMENT NMOS
       LL1 N1 N2 1
       DD1 N2 N3 D
       CC1 N3 0 10U
       RR1 N3 0 1K
-      SM1 N2 0 N4 0 ENH_SW
+      MM1 N2 N4 0 0 NMOS_ENHANCEMENT
       Vsimulation_voltage_source_0 N1 0 DC 5
       Vsimulation_voltage_source_1 N4 0 PULSE(0 10 0 1n 1n 0.00068 0.001)
       .END"
diff --git a/tests/examples/buck-converter.test.tsx b/tests/examples/buck-converter.test.tsx
index 65154e8..59cfc74 100644
--- a/tests/examples/buck-converter.test.tsx
+++ b/tests/examples/buck-converter.test.tsx
@@ -12,9 +12,9 @@ test(
 
     expect(spiceString).toMatchInlineSnapshot(`
       "* Circuit JSON to SPICE Netlist
-      .MODEL ENH_SW SW(Ron=0.1 Roff=1e9 Vt=2.5 Vh=0.1)
+      .MODEL PMOS_ENHANCEMENT PMOS
       .MODEL D D
-      SM1 N2 VP_IN VP_IN N1 ENH_SW
+      MM1 N2 N1 VP_IN VP_IN PMOS_ENHANCEMENT
       DD1 0 N2 D
       LL1 N2 VP_OUT 10
       CC1 VP_OUT 0 10U