Measured at 25°C with VGS=10 V and ID=30 A, the JMSH1003AGQ-13 MOSFET shows a typical RDS(on) near 3.1 mΩ and a junction temperature rise of ~22°C/W at 5 W dissipation on the test PCB, highlighting strong conduction capability paired with modest steady-state cooling requirements.
This article presents lab-measured electrical specifications, thermal characterization, the repeatable test methodology used, and application-focused design calculations for the JMSH1003AGQ-13 MOSFET so designers can reproduce results and apply the numbers in power-supply and motor-drive designs.
Device Overview & Why It Matters
Key Electrical Specifications
Point: Core specs determine fit-for-purpose: VDS, RDS(on), VGS(th), Qg, and absolute max ratings.
Evidence: Nominal VDS is 100 V; datasheet typical RDS(on) 2.8 mΩ @ VGS=10 V; measured VGS(th) ~2.5 V; measured total gate charge ~40 nC.
Explanation: These values drive selection for medium-voltage buck converters and synchronous rectifiers where low conduction loss and manageable gate drive energy matter.
Package & Thermal Path Impacts
Point: Package and PCB thermal path strongly affect RθJA and junction rise.
Evidence: The device uses a power package with exposed tab intended for PCB thermal attachment; measured thermal resistance depends heavily on board copper and vias.
Explanation: Larger mounting copper and thermal vias reduce RθJA dramatically; designers must allocate board area equivalent to at least 1–2 in² of copper per MOSFET.
Lab-Measured Electrical Performance
RDS(on) Measurements: Method & Variance
RDS(on) was measured using four-terminal pulsed current tests at controlled temperature. Test conditions: VGS=10 V and 8 V, currents 10–60 A, ambient 25°C, pulse width 200 ms to limit self-heating.
| Parameter | Datasheet Typical | Measured (25°C) | Comparison |
|---|---|---|---|
| RDS(on) @ VGS=10 V, ID=30 A | 2.8 mΩ | 3.1 mΩ |
|
| VGS(th) | ~2.5 V | ~2.5 V |
|
| Total Gate Charge Qg @ 10 V | ~40 nC | ~40 nC |
|
Switching Metrics & Losses
Evidence: Measured Qgs ~8 nC, Qgd ~12 nC, total Qg ~40 nC at VGS=10 V; rise/fall times ~30–60 ns with a 6–10 Ω drive.
Explanation: For a 48 V buck at 200 kHz, switching loss estimated using Esw ≈ 0.5·VDS·Qg gives ~0.2 W, making conduction loss the dominant term at moderate currents.
Thermal Performance: Data & Interpretation
Continuous Behavior
Measured RθJC ≈ 0.35°C/W and RθJA ≈ 40°C/W (1 in² copper). With 2 in² copper and thermal vias, RθJA drops to 8–10°C/W.
Pulse Response
Measured thermal time constant τth ~6–10 ms. Single-pulse energy keeping ΔTj
Test Methodology
- Fixture: 4-terminal Kelvin fixture on 2 mm FR-4 board.
- Control: Chamber at 25°C, high-bandwidth differential probes.
- Verification: Thermocouple at tab + Infrared (IR) verification.
- Processing: Averaging over 16 captures to filter noise.
Application Scenarios
Practical Selection & Thermal Checklist
Fit & Trade-offs
- Ideal for high-current/mid-voltage switching.
- Low RDS(on) (3.1 mΩ) minimizes cooling needs.
- Gate-charge energy becomes factor above 300kHz.
Best Practices
- Allocate ≥1–2 in² copper per device.
- Use thermal vias under the exposed tab.
- Limit junction temperature to ≤125°C.
Summary & Design FAQ
What is the actual measured conduction resistance? +
How much PCB copper is required for cooling? +
What are the switching trade-offs at high frequencies? +
How to handle transient or pulse events? +
