Key Differences Between SMT and Through-Hole DC Jacks

SMT and through-hole DC jacks perform the same basic function: connecting an external DC power source to a PCB. The main differences are their mounting method, mechanical strength, assembly process, space requirements, and suitable applications.

一. Basic Mounting Difference

An SMT DC jack is mounted directly onto copper pads on the surface of the PCB. It is normally placed by a pick-and-place machine and soldered during the reflow process.

A through-hole DC jack has leads or pins that pass through drilled holes in the PCB. The leads are soldered on the opposite side, creating both an electrical connection and a stronger mechanical anchor.

SMT vs. Through-Hole DC Jacks Feature

二. Mechanical Strength

Mechanical durability is one of the most important differences between the two types. A DC plug applies insertion and removal force to the jack. It may also create sideways pressure when the cable is pulled or moved.

A through-hole DC jack transfers part of this mechanical force through the PCB holes and soldered leads. This makes it a common choice for equipment exposed to vibration, repeated plug insertion, or accidental cable movement.

An SMT DC jack can also provide reliable performance, but its strength depends on the PCB layout and enclosure design. Larger copper pads, reinforced solder joints, positioning tabs, and a close-fitting housing opening can help reduce stress on the solder joints. Without sufficient support, repeated plug movement may lift the pads or damage the PCB.

三. Assembly and Production

SMT jacks are suitable for production lines that already use automated surface-mount assembly. They can be placed together with other SMT components and soldered in one reflow process. This can reduce manual operations and improve production efficiency, especially in high-volume manufacturing.

Through-hole jacks require additional PCB holes and a separate insertion and soldering process. If the product contains mostly SMT components, using a through-hole jack may require wave soldering or selective soldering after the SMT process. This can increase process time and manufacturing cost.

For prototypes, small batches, or products that require frequent repair, through-hole assembly may still be practical because the larger pins are easier to handle and resolder.

四. Size and PCB Layout

SMT DC jacks are generally better suited to compact PCB designs. Since they do not require leads to pass through the board, they leave more space for routing and may allow components to be placed on both sides of the PCB.

Through-hole jacks occupy more board space because of their leads and drilled holes. However, this structure can provide better mechanical retention. For a product with enough internal space, the additional board area may be an acceptable trade-off for improved durability.

五. How to Choose

An SMT DC jack may be appropriate when:

• The product has a compact PCB layout.

• The assembly process is mainly SMT and reflow.

• Production volume is high.

• The jack is protected by the enclosure.

• The power cable will not be exposed to strong pulling or repeated movement.

A through-hole DC jack may be more suitable when:

• The device is plugged and unplugged frequently.

• The product operates under vibration or mechanical shock.

• The jack is positioned on the outside of the enclosure.

• Long-term mechanical durability is a priority.

• The product is manufactured in small batches or requires easy repair.

In some designs, manufacturers use a mixed structure, combining SMT contacts for electrical connection with through-hole or reinforced mounting tabs for mechanical support. This approach can provide a balance between automated assembly and connector durability.

The choice between an SMT and a through-hole DC jack depends on the product structure and manufacturing requirements. SMT models support compact designs and automated production, while through-hole models generally offer stronger mechanical support for applications involving frequent connection, cable movement, or vibration. Selecting the right type requires checking the PCB footprint, plug dimensions, rated current, mounting space, assembly process, and expected mechanical load.