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ES Press-Fit vs Screw vs Solder Pin Terminals in Power Modules
Compare press-fit, screw and solder pin terminals in IGBT and SiC power modules: current paths, PCB and busbar requirements, rework limits and a practical selection checklist.
A power module’s electrical rating means little if the connection between the module and the rest of the converter cannot carry the current reliably for ten or fifteen years. Terminals are where the datasheet meets the real assembly line, and the choice between press-fit pins, screw terminals and solder pins affects PCB design, production yield, serviceability and long-term reliability.
This article explains how each terminal type works, where it is typically used, and what to check before you commit a design. It is written for engineers selecting IGBT modules and SiC modules for inverters, drives and power conversion systems.
Where Each Terminal Type Sits in a Module
Most industrial module packages use more than one terminal type at once. The high-current power terminals (DC+, DC−, phase output) and the low-current auxiliary pins (gate, emitter sense, NTC) have different jobs, so they are often built differently.
Infineon’s EconoDUAL 3 mounting note is a clear example: the power terminals are screw terminals for busbar connection, while the auxiliary terminals are available as either solder-only pins or PressFIT pins (Infineon AN2006-05). PCB-mounted families such as Easy modules offer solder pins alongside standard and high-current PressFIT pins (Infineon AN2023-07).
HIITIO Semi supplies modules in these same industry package families, including Easy 2B/3B, Econo Dual 3, Econo PIM and 62 mm. The exact terminal construction of each part is defined in its datasheet, so it should be confirmed against the datasheet before layout begins.
Press-Fit Pins
A press-fit pin is pressed into a plated through-hole in the PCB without solder. The pin is designed so that its contact zone deforms to form a gas-tight, solderless connection with the hole wall. The relevant general standard is IEC 60352-5, “Solderless connections – Part 5: Press-in connections,” which is cited in both the ZVEI press-fit recommendations and Infineon’s application notes.
What works well
- No soldering step. There is no reflow or wave exposure for the module, and the press-in operation is a single mechanical step. Infineon specifies a press-in speed of 25 to 100 mm/min per IEC 60352-5 for EconoDUAL 3.
- Repeatable joints. The connection is defined by pin geometry and hole quality rather than by solder wetting.
- Limited rework. Infineon states that a PressFIT module can be replaced up to two times, so a PCB can be used three times in total.
What to watch
- PCB hole quality is decisive. For Easy modules, Infineon specifies a 1.15 mm drill (minimum 1.12 mm, not milled), 25–50 µm copper in the hole, maximum 15 µm tin, and a final hole diameter of 0.99–1.09 mm. The ZVEI paper notes that the press-fit requirements must be agreed with the PCB manufacturer in advance because they can add cost and effort to board production.
- Surface finish matters. ZVEI lists HAL, lead-free HAL and immersion tin as having good slippage properties for press-in.
- Pin current is limited by the pin and the board. For Easy modules, Infineon rates a standard PressFIT pin at up to 25 A and a high-current pin at up to 50 A nominal. These figures are specific to that product family and should not be assumed for other packages.
- Mechanical loading. Infineon limits the force on each pin to 6 N and total pulling force on the module to 20 N, so the PCB must be supported appropriately.
Screw Terminals
Screw terminals clamp a busbar or cable lug directly onto the module’s power terminal. They are the standard solution where currents are too high for PCB pins, which is why they are common on 62 mm, Econo Dual and larger packages.
What works well
- High current paths. A busbar bolted to the terminal avoids routing hundreds of amperes through a PCB.
- Serviceable. A bolted joint can be opened, inspected and re-torqued without desoldering.
- Defined mechanical interface. Torque, screw class and thread engagement are specified.
What to watch
- Torque and thread engagement. For EconoDUAL 3, Infineon requires DIN M6 screws of at least class 6.8, tightened between 3 and 6 Nm, with thread engagement into the module not exceeding 10 mm. Over-engagement can damage the terminal; under-torque raises contact resistance.
- Busbar design. Because the busbar carries both current and mechanical stress, flatness, plating and support points affect the joint. Combination screws or suitable washers are called for in the same note.
- Parasitic inductance. The busbar geometry, not just the module, sets loop inductance in fast-switching SiC designs.
Solder Pins
Solder pins pass through PCB holes and are soldered, usually by wave or selective soldering. They remain widely used where manufacturers already operate a soldering line and do not want to change their PCB specification.
What works well
- Familiar process. Most electronics factories can solder through-hole pins without new tooling.
- Comparable current capability to press-fit. Vincotech’s pin current application note found that solder and press-fit pins show very similar temperature rise at a given current when tested in the same PCB track. The same note names ambient temperature and the number and thickness of copper layers as the main influences, and recommends testing the pin in the actual application.
- Simpler PCB hole spec. For Infineon’s soldered Easy pins the hole is D = 1.25 mm plus a tolerance X chosen per IPC-2222, rather than a tight press-in tolerance.
What to watch
- Thermal exposure during soldering. Infineon limits soldering to 260 °C for a maximum of 10 seconds and the module case temperature to 223 °C during the process.
- Permanent joint. Replacing a module means desoldering, which is harder on both the PCB and the part. Infineon notes that a module pressed out of a PCB cannot be pressed in again and can only be soldered to a new one.
- Board thickness. For Easy modules with solder pins, Infineon specifies PCBs up to 2 mm thick.
Side-by-Side Comparison
| Criterion | Press-Fit | Screw Terminal | Solder Pin |
|---|---|---|---|
| Typical role | Auxiliary and low-to-mid current PCB connections | High-current power terminals (busbar or lug) | Auxiliary and PCB-level connections |
| Joint formed by | Mechanical interference in plated hole | Clamped bolted joint | Solder fillet |
| Assembly step | Press-in | Torque-controlled tightening | Wave or selective soldering |
| Rework | Limited (up to 2 module replacements per Infineon Easy and EconoDUAL 3 notes) | Straightforward | Requires desoldering |
| Key process control | Hole size, copper thickness, finish | Torque, screw class, thread engagement | Soldering temperature and time |
| Main PCB requirement | Tight hole tolerance agreed with PCB maker | Not PCB-limited (busbar-based) | Standard through-hole spec |
| Example figure from vendor notes | 25 A / 50 A per pin (Infineon Easy, standard / high-current) | M6, 3–6 Nm (Infineon EconoDUAL 3) | 260 °C max, 10 s (Infineon) |
Some sources quote very low failure-rate figures for press-fit. For example, a Power Systems Design article on Wolfspeed’s WolfPACK modules cites 0.005 FIT for press-fit versus 0.5 FIT for screw and solder connections (The System Design Advantages of PressFIT Pins). That article is vendor-authored and gives no test conditions, so treat it as supporting context rather than a design input.
Choosing the Right Terminal Strategy
In practice, you rarely choose one terminal type for the whole module. The decision is usually made per connection and per package.
| Design question | If yes, consider | Reason |
|---|---|---|
| Is the phase or DC current in the hundreds of amperes? | Screw power terminals with a busbar | Keeps high current off the PCB |
| Do you need a solder-free, high-volume PCB assembly? | Press-fit auxiliary pins | Single mechanical step, no solder exposure |
| Does your factory already run a validated wave/selective solder line? | Solder pins | No new process qualification |
| Will modules be replaced in the field? | Screw power terminals; limit press-fit rework to the stated count | Serviceability |
| Is the PCB thick, heavily plated or exotic material? | Check the pin vendor’s hole and finish limits first | Press-fit tolerances are tight |
Several checks apply whichever option you choose:
- Read the datasheet’s mechanical section for terminal type, torque, hole size and maximum board thickness.
- Agree the PCB specification with your board maker before release when using press-fit.
- Validate current per pin in your own PCB layout, since copper layers and ambient temperature change the result.
- Handle modules with ESD controls and inspect before assembly. See HIITIO’s guides on storage and ESD handling of power modules and incoming inspection tests for power modules.
How This Applies to HIITIO Semi Module Families
HIITIO Semi lists IGBT and SiC modules in several established package families. A few examples from the live product pages:
- Easy 3B: HCG300FL120E3RA, a 1200 V, 300 A IGBT module in a 3-level NPC topology with 3.0 kV RMS isolation, an Al2O3 substrate on a copper baseplate and an integrated NTC.
- Econo Dual 3A: HCS900FH120D3C1, a 1200 V, 900 A half-bridge SiC module with a Si3N4 AMB substrate, 2.0 mΩ RDS(on), 175 °C maximum junction temperature and an internal thermistor.
- 62 mm: HCG300FH120A2E1, a 1200 V, 300 A half-bridge IGBT module with a low-inductance design.
These pages describe the electrical and thermal characteristics but do not specify terminal construction, so the terminal type, torque values and PCB hole requirements for each part should be taken from the datasheet supplied by HIITIO’s sales team. Applications where these package families are used include motor control and electric mining and construction machinery.
Get the Terminal Details Before You Lay Out the Board
Choosing a module is easier when mechanical details are confirmed at the same time as electrical ratings. HIITIO Semi supplies IGBT modules, SiC modules, SiC/Si hybrid modules and IGBT/SiC gate drivers for industrial, energy and mobility applications. If you are comparing packages for a new design, send your target voltage, current, topology and assembly method through the contact page. The team can recommend suitable modules from the IGBT and SiC ranges and provide the datasheet with terminal, torque and mounting information for review.
FAQ
Can press-fit pins be reused?
Only to a limited extent. Infineon states that a PressFIT module can be replaced up to two times, so a PCB can be used three times in total. A module that has been pressed out cannot be pressed in again; it can only be soldered to a new PCB.
Do solder pins carry less current than press-fit pins?
Not necessarily. In Vincotech’s pin current application note, solder and press-fit pins showed very similar temperature rise at a given current in the same test PCB. Actual capability depends on pin geometry, copper thickness and layer count, so validate it in your own layout.
Why do high-current modules use screw terminals?
Screw terminals let a busbar carry the main current directly, so hundreds of amperes do not have to pass through PCB traces. In Infineon’s EconoDUAL 3 package, the power terminals are screw terminals for busbar connection, while the auxiliary pins are solder or PressFIT.
What PCB requirements apply to press-fit pins?
They are specified by the pin manufacturer. For Infineon Easy modules, the note calls for a 1.15 mm drill, 25–50 µm hole copper, a maximum of 15 µm tin and a final hole diameter of 0.99–1.09 mm. The ZVEI paper recommends agreeing these requirements with the PCB manufacturer before ordering.
How do I know which terminal type a HIITIO module uses?
Check the part’s datasheet. The product pages on hiitiosemi.com list electrical and package information, and the datasheet provides the mechanical and terminal details. You can request it through the contact page.
