Introduction

In electronic design, small-pitch wire-to-board connectors are widely used for signal transmission and power interfaces. Due to their similar appearance across different series, engineers often face confusion in terms of pitch, current capacity, and lifecycle status. Such misjudgments can lead to PCB incompatibility, overheating from overcurrent, or long-term supply risks. To prevent these issues, it is critical to understand the positioning of each series and make accurate trade-offs during the design phase.

This article compares three representative models from JST — ZER-02V-S, B2B-PH-K-S, and B2B-XH-A — examining their parameters and application scenarios to help engineers make efficient and reliable selection decisions.

Parameter Comparison

Application Analysis

ZER-02V-S

With a 1.5 mm pitch and free-hanging design, the ZER series is well-suited for compact layouts and signal-level connections.

Typical applications include office equipment, household appliance control panels, and small-scale industrial interfaces.

B2B-PH-K-S

At 2.0 mm pitch and a 2A current rating, the PH series has historically been popular in consumer electronics.

Rated for 100V, it fits light-load scenarios but has now reached EOL status, which limits its suitability for new designs.

It still plays a role in legacy system maintenance where compatibility is critical.

B2B-XH-A

Featuring a 2.5 mm pitch and 3A current capacity, the XH series is more robust and ideal for higher-current applications.

Through-hole mounting ensures mechanical strength, making it a common choice for motor drives, industrial equipment, and lighting systems.

Design Considerations

Pitch Differentiation

Although 1.5 mm (ZER), 2.0 mm (PH), and 2.5 mm (XH) appear similar, PCB design and connector compatibility require strict distinction.

Current Capacity

XH supports up to 3A, making it suitable for power circuits.

ZER and PH are better suited for low-current or signal-level use.

Lifecycle Risks

PH series models are obsolete (EOL). Incorporating them into new projects introduces significant supply and maintenance risks.

Mounting styles

ZER uses free-hanging sockets for wire harnesses.

PH and XH employ through-hole headers, better suited for fixed, mass-production assemblies.

Common Pitfalls

Focusing only on appearance while ignoring series differences: ZER, PH, and XH connectors look very similar. In urgent procurement or replacement situations, engineers may rely only on pitch and pin count, overlooking current and voltage ratings, which leads to mismatched performance.

Overlooking Current Requirements: Using ZER or PH in higher-current applications can cause overheating.

Ignoring Lifecycle Status: Designing with EOL PH series connectors can create long-term maintenance challenges.

Replacement & Migration

PH → ZER/XH

As many PH series models are already EOL, they should be avoided in new designs. Migration can be made depending on application needs:

ZER series: Best for compact layouts and low-current signal use.

XH series: Suitable for higher current and industrial-grade applications.

ZER vs. XH

Both series remain active, with a clear selection logic:

For compact form factors and signal-level applications → ZER series.

For higher current capacity and stronger mechanical requirements → XH series.

ZER-02V-S: Ideal for compact layouts and light signal connections, widely used in office and home appliance designs.

B2B-PH-K-S: A once-common 2.0 mm pitch solution for consumer electronics, now obsolete; suitable only for legacy maintenance.

B2B-XH-A: Higher current capacity and robust mechanical design make it a reliable choice for industrial and power-related applications.

Key Takeaway

ZER = Compact signal

PH = Consumer lightweight (EOL)

XH = Industrial high-current

WIN SOURCE provides JST connector series including ZER, PH, and XH, covering both active and obsolete models. Engineers can quickly select and order based on project needs. Visit WIN SOURCE to check real-time inventory and lead time, and avoid project delays.