JST Connector Types: Electrical Terminals for Wire-to-Wire or Wire-to-Board Connections
Electronics need circuit boards, but these PCBs cannot function independently. They need connections to peripheral devices and other components to augment their performance. Some of the most typical terminals used to make these connections are JST connectors. However, these terminals come in different types with varying features for specific applications. We will look at the features of these JST connector types and explain their most suitable applications. Let's get right into it!
What is a JST Connector?
JST refers to Japan Solderless Terminal. These terminals are electrical connectors built by a Japanese company bearing the same name, JST Mfg. Co. The term generally refers to different types of connectors fabricated to meet the design standards developed by the original manufacturer.
JST connectors
These connectors are available in thousands of different types that fall into several series and are ideal for specific applications. But all types help bridge electrical connections to carry electrical signals between wires or from a wire to a board.
JST Connector Types
These connectors fall into two categories: wire-to-wire and wire-to-board.
JST Connector Types: Wire-To-Wire Connection
The most typical solderless terminal units in this category include the following.
SM (2.5mm Pitch)
SM is exclusively a wire-to-wire connector type that has become quite popular for electrical connections. The Japan Solderless Terminal can handle three amperes at 250V and fits eight 28-22 AWG wires. Additionally, it has a high force/contact pressure secure locking mechanism and features toolless mounting on panels of various thicknesses. SM connectors are typical in decorative RGB LED strip lights.
RGB LED strip light connectors
RCY (2.5mm Pitch)
RCY is a compact, 2-position type of connector suitable for various signal and power supply circuits. Besides its tight size advantage, the unit features free spring terminals that ensure stable performance and easy insertion/removal.
JST RCY connectors
It has the same current and voltage rating as the SM connector and is typical in radio control devices (such as toys). Also, you can find it in compact Lithium Polymer batteries as a battery connector.
JST Connector Types: Wire-To-Board Connection
The typical wire-to-board JST connector that offers the most reliable connection includes the following.
SR/SH (1mm Pitch)
This 1mm pitched pin connector has a compact, low-profile design with wings on the sides. These receptacles help with disconnection without holding the wires. The housing is SH, while the header is SR.
While the shrouded SR header has a locking feature for its mating receptacle, it does not have holes that can affect vacuum gripping equipment.
SH connectors have current and voltage ratings of 1A and 50V, respectively. And they connect to 32-28 AWG wires. Also, they are compatible with SZ and SR IDC series connectors.
SHD (1mm Pitch)
SHD JST connectors are similar to the SH type above but are larger versions with two rows of pins. They are typical in LVDS and LCD applications.
An LVDS connector
GH (1.25mm Pitch)
GH connectors feature a pin-to-pin pitch of 1.25mm with a low-insertion force and positive latching mechanism for easy use. The contact section is similar to the SHL connector and has a secure locking mechanism.
A JST 1.25 male connector for small RC vehicles
Also, it can handle 1A at 50V but connects to 30-26 AWG wires. Some people confuse it with the Molex connector family, specifically the PicoBlade.
ZH (1.5mm Pitch)
This connector is one of the tiniest pitch JST types for a thru-hole wire-to-board connection. The other smaller types above are all for SMD connectivity. The unit features a dimple in the middle to create a positive terminal contact with low resistance. Also, it has a fully shrouded header and is compatible with ZM (crimp) and ZR (IDC) series connectors.
PA (2mm Pitch)
The PA JST connector can handle three amperes at 250V, which is high. So it has a secure locking device to avoid accidental disconnections caused by vibrations when routing wires. They connect to 28-22 AWG wires and are popular battery connectors in RC FMA Cellpro battery chargers.
A JST connector
PH (2mm Pitch)
PH connectors have relatively low power ratings compared to the PA (2A at 100V). So they don't have secure locking devices. But they can meet the demands of high-density connections of internal wires to computer circuit boards.
Also, they are typical in stepper motors and are compatible with CR, KR, and KRD IDC series connectors. Another key selling point of these terminals is their affordability.
XA (2.5mm Pitch)
XA connectors have similar power requirements to PA terminals but connect to 30-20 AWG wires. They feature secure locking devices to prevent accidental connections and have header wafers built using glass-filled PA66 nylon, a solder crack preventive material.
Additionally, they contain circular, reflow-treated header pins that provide a low insertion force. Shrouded headers on radial tape and headers with polarizing bosses are also available.
XH (2.5mm Pitch)
Based on the versatile and reliable NH series connectors, XH terminals are slightly bigger than their PH counterparts but with a 2.5mm pitch. However, they are still compact with a 9.8mm mounting height. The terminals are typical in low-cost consumer electronics.
A JST-XH battery plug connector
EH (2.5mm Pitch)
Like PH terminals, the EH type is a perfect choice for high-density connections of wires internally to computer boards. It features a shrouded header but without a secure locking device. And it can handle 3A at 250V, connecting the power flow to 32-22 AWG wires.
RE (2.54mm Pitch)
RE connectors are similar to male pin headers and female DuPont connectors. They are non-shrouded and don't have a locking mechanism but feature double leaf-springs that can withstand repeated mating and unmating stresses. The terminals are ideal for connecting office automation equipment, such as computers and their peripheral devices.
VH (3.96mm Pitch)
VH terminals have high current-carrying capacities of up to 10A at 250V, making them suitable for several power-supply, signal, and output circuits in consumer electronics. They are available in shrouded and non-shrouded varieties, but each has a positive latching mechanism. And they connect to broader wires (22-16 AWG) to handle the high current flow.
The list doesn't end there. Other JST connectors in the product range include the following.
A Lithium Polymer battery with its connectors
- J-FAT
- BMSC
- CPM
- FAH
- GEZ
- SJG
- PBD
- BNI
- HYV
- And more
Connector Terminology
You will discover the following terminologies when going through each connector JST builds.
- Gender: Female connectors get plugged into while male connectors plug in. The female connector might appear as a male pin and vice versa, but the one with the pins is always the male terminal. This distinction will help you buy the ideal mating connector for your project.
- Polarity: Also known as keying, this term describes terminals that connect only in one direction.
- Pitch version: Connectors have several pins, and pitch defines the distance from the center of one pin to the center of the adjacent one.
Spaced pins mean a larger pitch
- Shrouding: Connector shrouding is the boxing of pins (surrounding and protecting them with sidewalls).
- Contact: Contacts are the business portion of the connector. They comprise the metal pieces or pins that touch each other to transmit power or signals.
- Mount: Mounting refers to how the connector gets mounted for use. With JST terminals, it is usually a surface mount (SMD) or thru-hole board mount connector.
- Mating Cycles: A mating cycle refers to connecting and disconnecting the terminals. A reliable connector type should have a high mating cycle count, which shows it can withstand the plugging and unplugging stresses several times.
Male and female connectors for automotive applications
- Strain Relief: The connector-to-wire link point is fragile, and some terminals provide strain relief features to place the pressure or strain on a more mechanically-sound object.
Summary
In conclusion, JST connectors come in a wide variety, each suitable for specific applications. And they are necessary for PCB connections in most computers and consumer electronics
