ClassA Motor

Sub-assembly

Hall Sensor Board (PCBA)

The small board at the stator end that carries three Hall ICs to sense rotor position for commutation. Hall position accuracy directly sets commutation timing, so placement, soldering and mounting on the stator are the critical points.

✓ Expert reviewed All content on this page has been reviewed by a senior motor engineer.

Component BOM

Electronic and other components, grouped by function (not part numbers). ★ marks items critical to performance.

PartMaterialKey specificationQtyRepresentative suppliers
Bare PCBPrinted Circuit Board (bare board)Purchased componentFR-4, 1.0–1.6 mm, single or double sided, OSP or ENIG finish1SuntakShenzhen, KinwongShenzhen, FastprintGuangzhou+1 more →
★Hall ICsHall-effect Sensor ICPurchased componentLatch type, -40–150 °C, open-collector output3Allegro MicroSystemsShenzhen, Dream ElectronicsShenzhen, SekormShenzhen+2 more →
Pull-up resistors and decoupling capacitorsPassive Components (chip resistors, MLCC)Purchased component0603 / 0805 chip partsPer schematicFenghuaZhaoqing, EYANGShenzhen, MilliohmShenzhen+1 more →
Hall lead wires and connectorLead Wires & ConnectorsPurchased component5-core lead (power, ground, Hall A / B / C), UL1007 26 AWG, with connector1 setMolexShenzhen, WoerShenzhen, XSD CableDongguan+2 more →
Solder pasteSolder Paste (lead-free)Auxiliary materialLead-free SAC305, type 4 powder, no-clean fluxAs requiredVitalShenzhen, Yik Shing TatShenzhen, Jufeng SolderShenzhen

Process flow

4 main process steps, with the equipment and instruments used at each step, their main suppliers, and the technical control points.

  1. 1

    Solder-paste printing & SPI

    Solder paste is printed through a stencil and its volume inspected.

    ⚙ SMT Line (printer, SPI, placement, reflow, AOI)Automated
    International
    Koh YoungShenzhen, ASMPT, FUJI Corporation+1 more →
    Mainland China
    GKGDongguan, JT AutomationShenzhen

    Technical control points:

    • ▪Paste volume and offset — Volume 70–130% of nominal; offset ≤ 25% of padCheck: SPI; 100%
    • ▪Stencil cleaning — Every 5–10 printsCheck: Printer setting; verified each shift
  2. 2

    Placement & reflow

    Hall ICs and passives are placed and reflow-soldered.

    ⚙ SMT Line (printer, SPI, placement, reflow, AOI)Automated
    International
    Koh YoungShenzhen, ASMPT, FUJI Corporation+1 more →
    Mainland China
    GKGDongguan, JT AutomationShenzhen

    Technical control points:

    • ▪Hall IC position and orientation — Position ±0.05 mm, correct orientation — sets commutation timingCheck: AOI; 100%
    • ▪Reflow profile — Lead-free SAC305: peak 235–250 °C, time above liquidus 45–90 sCheck: Profiler; each shift and changeover
    • ▪ESD protection — Per IEC 61340-5-1Check: Wrist-strap / grounding checks; daily
  3. 3

    AOI & electrical test

    Joints are optically inspected and boards functionally tested before depaneling.

    ⚙ SMT Line (printer, SPI, placement, reflow, AOI)Automated
    International
    Koh YoungShenzhen, ASMPT, FUJI Corporation+1 more →
    Mainland China
    GKGDongguan, JT AutomationShenzhen

    Technical control points:

    • ▪Solder-joint quality — IPC-A-610 Class 2 (Class 3 for automotive)Check: AOI; 100%
    • ▪Hall output function — All three outputs switch correctly with a test magnetCheck: Functional tester; 100%
    • ▪Depaneling stress — Board strain ≤ 500 µε near componentsCheck: Strain gauge; at setup
  4. 4

    Lead-wire soldering & final inspection

    Lead wires are soldered to the board pads, sleeved or potted, and each board is checked before it goes to motor assembly.

    ⚙ Soldering Robot / Soldering StationAutomatedSemi-automaticManual
    International
    To be added
    Mainland China
    JT AutomationShenzhen, ATTENShenzhen, QuangangDongguan

    Technical control points:

    • ▪Lead solder joints — IPC-A-610 Class 2; no cold joints or bridgesCheck: Visual / magnifier; 100%
    • ▪Wire order and pull strength — Colours match power / ground / Hall A, B, C per drawing; pull strength per drawingCheck: Visual check; pull test on samples

Reliability tests

  • Temperature cycling of solder jointsIPC-9701 (e.g. -40 / +125 °C, 500–1,000 cycles)
  • Hall switching points over temperature-40–150 °C with a test magnet or on the motor
  • Damp heat with biasIEC 60068-2-78 (e.g. 85 °C / 85% RH)
  • ESD on the lead wiresIEC 61000-4-2, level per customer requirement

Assembly-level tests for product validation; incoming tests for each component are on its material page.