Five-pin Magnetic Wiring: Assignments, Views and Validation

• What the Contact Assignment Defines
• Six Example Wiring Arrangements
• An Example Power-and-data Layout
• Documenting Both Mating Views
• Current Paths and Contact Heating
• Signal Routing and Stability
• Detection and Power-control Timing
• Choosing a 90° or 180° Cable Exit
• Board and Housing Integration
• Sealing the Rear and Cable Exit
• Designing Against Corrosion
• Documenting Cable Colors
• Prototype Verification
• Application Examples
• Inputs for a Custom Cable Drawing

A five-contact magnetic interface can combine charging, data, detection and control. This guide covers example assignments, mapping between mating halves, power and signal routing, 90° and 180° cable exits, sealing and the tests needed before sample approval and production.

What the Contact Assignment Defines

A pinout assigns an electrical role to each contact. Similar-looking five-contact parts can be wired differently, so external appearance does not establish compatibility.

One project may use the five pins for:

• Pin 1: Power

• Pin 2: Ground

• Pin 3: Data+

• Pin 4: Data-

• Pin 5: Device Detection

Another device may use:

• Pin 1: Power

• Pin 2: Ground

• Pin 3: Transmit Signal

• Pin 4: Receive Signal

• Pin 5: Identification or Control

For charging only, a design may use parallel power or return contacts according to its current and space requirements. Evaluate current sharing and the entire supply-and-return path.

Do not copy the colors or contact order of an unrelated cable. Before assembling samples, agree the mating-face drawing, wire definitions, PCB layout and electrical schematic for the actual pair.

Six Example Wiring Arrangements

These arrangements illustrate engineering options; none is a mandatory five-pin standard.

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Let the device requirements determine the contact assignment. Establish these inputs before allocating the five contacts:

• Required charging current and voltage

• Signal protocol and data rate

• Whether hot plugging is allowed

• Whether device detection is needed

• Available PCB space

• Contact sequence during mating

• Cable wire gauge and shielding

• Waterproof and corrosion requirements

An Example Power-and-data Layout

For a low-voltage product with charging and basic communication, the following is one possible layout:

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With the appropriate circuit, this compact layout can provide charging, communication and detection through the same interface.

Set the physical contact order with return paths and noise in mind. Closely adjacent power and signal contacts without a suitable return can expose communication to charging-switch noise. A center ground or a ground between power and signal contacts is an option for sensitive signals, subject to the complete layout and protocol.

Documenting Both Mating Views

A change of viewing direction between the two connector drawings can lead to a wiring error.

For example, copying an order shown at the device mating face onto a cable-side rear or solder-side view can reverse contacts 1 and 5. The actual mapping depends on both viewing directions and the keying geometry.

Every drawing should clearly indicate:

• Mating-face view or rear view

• Male-side contact numbering

• Female-side contact numbering

• Cable wire colors

• Magnet polarity

• Connector orientation mark

• PCB pad numbering

Use a drawing note that defines the relevant views, for example:

Contact numbers refer to the specified mating-face view. Map the cable-side contacts to the complementary mating arrangement using the defined views, orientation marks and contact-to-net drawing.

Before applying power, check continuity and unintended shorts with the circuit isolated. Confirm the approved mapping between the mating halves.

Current Paths and Contact Heating

Five contacts do not define a current rating. Contact diameter and material, spring force, travel, resistance, plating, wire gauge, PCB copper and ambient temperature all contribute to the complete path’s limit.

The power loss at a contact can be estimated using:

Power loss = Current² × Contact resistance

A small resistance increase can produce significant heating at higher current. Contamination, insufficient compression, worn plating or misalignment can increase that resistance further.

During development, engineers should test:

• Contact resistance before and after mating-cycle testing

• Connector temperature under continuous load

• Temperature at the solder joint and cable outlet

• Voltage drop across the complete cable assembly

• Performance at minimum and maximum working stroke

• Behavior after salt-spray or humidity exposure

Parallel power or return contacts can add current-carrying area, but unequal resistance can produce uneven current sharing. Verify temperature rise and voltage drop through the complete circuit, including any single-contact return path.

Signal Routing and Stability

Low-speed communication, detection, sensing and control are possible five-contact functions. Higher-speed communication needs a more detailed interface and signal-integrity assessment.

Signal performance is influenced by:

• Pin spacing

• Ground-return location

• Cable length

• Wire twisting or shielding

• Connector geometry

• Contact resistance variation

• Cable routing near power circuits

• Mating movement and vibration

Give a differential pair appropriately matched electrical paths and controlled cable routing for its protocol. Its ground reference must not rely on an undersized or intermittent contact.

Communication on an open bench does not establish installed performance. Test the sample inside its intended enclosure with the specified cable length, charger, PCB and firmware.

Detection and Power-control Timing

The fifth contact can be allocated to device detection, charger or accessory identification, temperature sensing or power-enable control. Its role comes from the device architecture.

A detection pin can help the system:

• Confirm that the connector is fully seated

• Enable the charging circuit after stable contact is established

• Disable power before disconnection

• Identify an approved cable or accessory

• Switch the device into docking mode

• Monitor a thermistor or other sensor

Large input capacitors and frequent hot plugging make controlled enabling particularly relevant. Instead of energizing the interface at the first touch, a suitable circuit can detect mating and apply power after a defined delay. Debounce, inrush and sequencing still need validation.

Different contact heights can help control the mating sequence, subject to mechanical tolerances and test results. A longer detection pin can touch first before the main contacts seat, but it commonly separates later; it does not by itself ensure that power is disabled before separation.

Choosing a 90° or 180° Cable Exit

A 90° exit and a 180° exit may use the same electrical contact assignment. The primary distinction is cable routing and its associated mechanical geometry.

90° 5 Pin Magnetic Data Cable

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A side-entry exit, described here as 90°, may suit a cable that must stay near the enclosure or where straight routing has insufficient rear clearance. Confirm the angle convention on the approved drawing.

Common applications include:

• Wearable charging equipment

• Side-mounted industrial controllers

• Medical electronics

• Compact handheld devices

• Devices installed against a wall or panel

Allow for overmold dimensions, bend radius, pull direction and strain relief. A side exit can reduce a bend directly behind the head, but an unsuitable orientation can introduce rotational load.

180° 5 Pin Magnetic Data Cable

View image

A straight exit, described here as 180°, can suit open mounting space, docks, test equipment, robots or handheld terminals. Compare the actual route and clearances for the assembly.

The straight structure generally offers:

• Direct cable routing

• Easier assembly in open housings

• Simpler cable replacement

• Clearer strain direction

• Convenient connection to desktop charging bases

Choose the exit from the housing drawing and expected cable movement, rather than appearance alone.

Board and Housing Integration

A correct wire assignment is only part of reliable contact. Integrate both mating halves with the PCB and housing so the mechanical stack maintains their electrical connection.

Engineers should review:

Working height

After mating, each pogo contact should remain within its specified compression range. Too little compression can allow dropouts; too much can damage the spring or housing.

Coplanarity

Account for pin-height variation, PCB warp, housing deformation and assembly tolerances. All five contacts must seat as intended; a signal can remain open even while the power contacts conduct.

Magnetic force

Set enough retention for normal device movement without making release unnecessarily difficult or overloading the board, cable or mounting structure.

Mounting method

Possible structures include:

• SMT mounting

• THT / through-hole electrical termination

• Wire-solder connection

• Embedded housing installation

• Panel mounting

• Overmolded cable assembly

Choose the mounting combination around assembly methods, board area, operating loads and the sealing plan.

Sealing the Rear and Cable Exit

Sealing only the contact face is insufficient. Water can reach the rear joints, cable exit, plastic-to-metal boundary, mounting opening or the interface between the connector and enclosure.

Depending on the project, the sealing structure may include:

• Rear adhesive sealing

• Potting compound

• O-ring

• Gasket

• Overmolded cable head

• Sealed mounting recess

• Waterproof housing interface

Verify IP65, IP67 or IP68 targets on the complete installed assembly. A rated connector component does not automatically give the finished device the same protection.

Define sealing requirements before finalizing the enclosure and cable tooling. Seal features can alter connector dimensions and installation clearances.

Designing Against Corrosion

Sweat, humidity, salt mist, cleaning chemicals and condensation can affect contacts in wearable, outdoor, medical or industrial products, raising resistance or interrupting charging and data. Match protection to the actual exposure.

The engineering review should consider:

• Contact base material

• Gold or composite plating

• Plating thickness

• Nickel barrier layer

• Magnet corrosion protection

• Plastic material

• Drainage and cleaning access

• Mated and unmated exposure

• Required salt-spray duration

Relevant verification includes plating-thickness checks, salt spray, controlled temperature-and-humidity exposure, microscopy and resistance measurements before and after environmental tests.

A desktop interface, pet tracker, medical wearable and outdoor sensor face different exposure. Select the contact finish and protective structure for the actual environment.

Documenting Cable Colors

Colors assist assembly, but the approved pinout remains the authority. The table gives one possible custom cable color scheme:

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This color scheme is an example only. Other factories, cables and projects may assign different colors.

The approved cable drawing should include:

• Pin number

• Wire color

• Wire gauge

• Cable length

• Terminal type

• Shielding requirement

• Continuity definition

• Cable outlet direction

• Connector part number

• Tolerance

Production continuity checks should cover all five assigned paths and detect shorts between neighboring contacts. Contact count does not imply five independent complete circuits.

Prototype Verification

Complete both electrical and mechanical verification before releasing a custom five-contact cable assembly for production. Agree test conditions and acceptance criteria for the project.

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Where possible, evaluate the sample in the intended board and enclosure. A part that passes isolated tests can still fail due to mounting-height tolerances, housing fit, cable clearance or firmware timing.

Application Examples

Consider five contacts where charging must share an interface with one or more auxiliary functions.

Typical applications include:

• Smartwatches and fitness trackers

• Smart rings and wearable charging docks

• Behind-the-ear electronic devices

• Portable medical electronics

• Smart locks and removable control modules

• POS terminals and barcode scanners

• Industrial tablets

• Pet trackers

• Smart mugs and heated cup bases

• Test equipment

• Robots and sensor modules

• Portable consumer electronics

Five contacts can allocate power, return, detection, ID, data or control in a custom geometry. Compare the enclosure integration with a conventional USB opening; the interface still needs its own approved mounting and sealing structure.

Inputs for a Custom Cable Drawing

Provide these inputs when developing a custom five-contact assignment:

• Device application

• Housing drawing or 3D model

• Available connector dimensions

• PCB layout

• Required pin assignment

• Current and voltage

• Signal type and data rate

• Mounting method

• Desired magnetic force

• 90° or 180° cable direction

• Cable length

• Wire gauge

• Cable-end connector

• Waterproof requirement

• Environmental exposure

• Sample quantity

• Estimated production volume

Use these inputs to review structure, contact arrangement, wiring, plating, polarity and sealing before approving samples.

Wiring Design Questions

Is There a Universal Five-contact Assignment?

No. The device circuit determines how the five contacts carry power, return, data, detection, ID or control. Confirm the approved mating-face views and wire definitions for the actual pair.

What Is Required to Carry Power and Data Together?

Evaluate contact layout, cable construction, signal type, ground paths, current load and connector geometry for the application. Higher-speed communication may require additional signal-integrity testing.

What Must Be Checked Before Paralleling Contacts?

Parallel power or return contacts need current-sharing assessment across resistance, spring force, compression, board routing and cable construction. Verify temperature rise and voltage drop; do not simply add nominal contact ratings.

Which Roles Can the Fifth Contact Have?

Detection, identification, control, temperature sensing or another data path are possible roles. Define one appropriate function or a supported circuit arrangement for the device.

Does the Cable Exit Determine the Pinout?

No fixed change is required. A 90° and a 180° exit can share an assignment while differing in exit direction, overmold, bend radius and installation space. Confirm each assembly drawing.

How Is Sealing Performance Established?

A custom structure can be developed toward IP65, IP67 or IP68 requirements. Rear seals, overmolding, enclosure installation and gasket design must be evaluated by complete-device testing.

Releasing a Documented Design

Begin with the circuit and mechanical stack, rather than a generic cable color scheme. Before releasing drawings, define current paths, signals, detection logic, mapping between both halves, mounting height, retention, cable route and environmental exposure.

A suitable five-contact pogo interface can combine charging, data, ID and control while easing alignment and limiting insertion wear. A 90° or 180° cable may use the same pinout, but its clearance, strain relief and installation direction still need validation inside the final enclosure.