When evaluating high-power semiconductor devices such as Insulated Gate Bipolar Transistors (IGBTs), two complementary test approaches are essential: static characterization and dynamic testing.

Each method examines a different side of device behavior — one is about verifying datasheet limits, the other about understanding real-world switching performance.
Knowing where one ends and the other begins is key for correct interpretation.

In this article, we’ll use IGBTs like the ON Semiconductor NGTG50N60FWG or the Toshiba GT50J325 as a concrete examples, along with two test setups:

• IWATSU CS-8500 Semiconductor Curve Tracer (static)

• Double-Pulse Tester with PMK & IWATSU probes (dynamic)

1. Static Characterization — The Foundation

Static testing measures device parameters under steady-state or slowly varying conditions.
The goal is to verify DC specifications that define the device’s fundamental capability to block voltage, conduct current, and maintain leakage within limits.

With an IWATSU Semiconductor curve tracer, you can plot a wide range of curves, for example:

• Output characteristics: $I_C$ vs. $V_{CE}$ at fixed $V_{GE}$

• Transfer characteristics: $I_C$ vs. $V_{GE}$ at fixed $V_{CE}$

• Leakage current curves: $I_{CES}$, $I_{GES}$

Example — NGTG50N60FWG key static parameters:

• Collector–Emitter Breakdown Voltage:
  $V_{(BR)CES} = 600 \ \text{V} \ @ \ I_C = 500 \ \mu\text{A}$

• Collector–Emitter Saturation Voltage:
  $V_{CE(sat)} = 1.45 \ \text{V} \ \text{typ.}, \ V_{GE} = 15 \ \text{V}, \ I_C = 50 \ \text{A}$

• Gate–Emitter Threshold Voltage:
  $V_{GE(th)} = 5.5 \ \text{V} \ \text{typ.}$

• Gate Leakage Current:
  $I_{GES} \leq 200 \ \text{nA}$

Static conduction loss calculation:

$$P_{\text{avg}} = V_T \times I_{T(\text{AV})}$$

For $V_T = 1.45 \ \text{V}$ and $I_{T(\text{AV})} = 50 \ \text{A}$:

$$P_{\text{avg}} = 1.45 \times 50 = 72.5 \ \text{W}$$

This is the type of loss you see during conduction before switching is even considered.

Static Test Setup

IWATSU curve tracers provide dedicated test fixtures that allow safe and convenient accommodation of the IGBT.

In this example, a CS-8500 main frame is used in combination with a CS-220 high-current unit, and a CS-322 test fixture. The test fixture CS-322 is further equipped with a CS-520 patch panel and a CS-501A adapter.

The gate and emitter are wired according to the measurement mode (e.g., leakage, output, transfer), and the tracer sweeps voltage while measuring current. For leakage current (ICES), the gate is shorted to the emitter and a specified VCE is applied, with current measured in the nanoamp to milliamp range.

2. Dynamic Testing — Real-World Switching Behavior

Dynamic testing begins when the device is evaluated under high-speed switching conditions, where parameters depend on time, parasitics, and load.

A double-pulse tester is the industry-standard tool for this.
It applies two voltage/current pulses to the device under test, allowing you to observe:

• Turn-on & turn-off waveforms

• Switching losses ($E_{\text{on}}, E_{\text{off}}$)

• Body diode reverse recovery

• Surge voltages and ringing

Why a double-pulse test is different from static testing

• Horizontal axis: In a curve tracer, it’s voltage; in a double-pulse test, it’s time.

• Connection method: Curve tracers use fixed internal pins; double-pulse testers require external dynamic probes and sockets.

• Influence of setup: Parasitic inductances and capacitances in the wiring/jigs can significantly distort waveforms — even the same device can look different depending on who performs the test.

Example — NGTG50N60FWG Dynamic Parameters

(Conditions: $V_{CC} = 400 \ \text{V}, I_C = 50 \ \text{A}, R_G = 10 \ \Omega$)

Switching loss calculation:

$$P_{\text{sw}} = (E_{\text{on}} + E_{\text{off}}) \times f_{\text{sw}}$$

For $E_{\text{on}} + E_{\text{off}} = 2.3 \ \text{mJ}$ and $f_{\text{sw}} = 20 \ \text{kHz}$:

$$P_{\text{sw}} = 2.3 \times 10^{-3} \times 20 \times 10^{3} = 46 \ \text{W}$$

Dynamic Test Setup

Example demo setup for dynamic testing such as double-pulse tests. The entire test rig can be tightly fixed to the Skid platform by hand-tightening the 3D-positioners and placed inside an explosion-safe enclosure. Products shown in the illustration:

• Skid®
• 3D-Positioner
• Optical probe head FireFly®
• High-Speed Differential Probe HSDP 
• Differential probe BumbleBee®
• 4-mm test point adapters

Dynamic testing often uses a double-pulse tester to measure instantaneous switching events. In such a setup:

1. The DUT is mounted in a socket with minimal parasitic inductance.

2. A large current pulse is applied through the device.

3. High-speed probes (e.g., PMK FireFly high-voltage differential probe) connect to an oscilloscope.

4. The oscilloscope displays voltage and current waveforms vs. time.

From these waveforms, engineers can determine (selection):

• Turn-on/turn-off energy loss

• Reverse recovery behavior of the body diode

• Overshoot voltage and ringing due to parasitics

3. Static vs. Dynamic — Side-by-Side

4. Where One Ends and the Other Begins

• Static testing ends when the device transitions from a steady bias into a switching event.
  It confirms the device is fundamentally healthy and within datasheet DC limits.

• Dynamic testing begins when evaluating how it switches: speed, losses, and stresses at real operating conditions.

Best practice:

1. Start with static — verify safe operation limits.

2. Move to dynamic — optimize performance for your circuit, switching frequency, and load.

Interested in static or dynamic testing? We're here to help! Send us an email and tell us your questions and requirements: sales@pmkamerica.com.