4 layers23 × 40 mm
BTM308-host bottom
KingJacker/BTM308-bluetooth-module-host
This is a carrier board for the BTM308 Bluetooth audio module.
36 parts
4 layers52.8 × 40.1 mm
BTM308-host
KingJacker/BTM308-bluetooth-module-hostThis is a carrier board for the BTM308 Bluetooth audio module.
- Size
- 52.8 × 40.1 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 52
- Nets
- 68
- Pads
- 195
- Tracks, vias
- 322, 144
- Pours
- 7
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 24 Sep 2025
- Updated
- 20 Oct 2025
Overview
BTM308-host is an open-source printed circuit board by KingJacker, from the KingJacker/BTM308-bluetooth-module-host repository on GitHub. It is a 4-layer board of 52.8 × 40.1 mm with 52 parts on 68 nets, routed with 322 tracks and 144 vias.
It is built around the OPA1678ID, PJ-320A and SMAJ6.0A. Its parts include 21 resistors, 13 capacitors, 7 connectors, 5 switches and 3 ICs.
Main components
3
OPA1678ID
SOIC-8-150mil-18V~-2.25V、2.25V~18V -40℃~+85℃ 10pA 10pA 110dB 16MHz 2 2mA 2uV/℃ 4.5V~36V 4.5nV/√Hz@1kHz 500uV 50mA 9V/us Built-in compensation、ESD protection Rail-to-rail output SOIC-8-150mil Operational Amplifier ROHSTexas InstrumentsAudio Amplifiers
PJ-320A
插件-20℃~+70℃ 3.5mm Headphone Jack 30V 500mA 插件 Audio Connectors ROHSXKB ConnectionAudio Connectors (Headphones)
SMAJ6.0A
DO-214AC(SMA)-65℃~+150℃ 10.3V 38.8A 400W@10/1000us 6V 7.37V 800uA IEC 61000-4-2、IEC 61000-4-4 TVS Unidirectional DO-214AC(SMA) ESD and Surge Protection (TVS/ESD) ROHSLittelfuseESD And Surge Protection (TVS/ESD)
README
README.mdHost Board for BTM308 Bluetooth Audio Receiver
This is a carrier board for the BTM308 Bluetooth audio module.
Schematic
BTM308
Differential OP-AMP (OPA1678)
Board to Board Interface
Layout
| Top | Inner 1 | Inner 2 | Bottom |
|---|---|---|---|
 |  |  |  |
Assembly
Bill of Materials
| Designator | Footprint | Qty. | Designation |
|---|---|---|---|
| C4 | C_0805_2012Metric | 1 | 100nF |
| C8,C6,C7,C9 | C_0805_2012Metric | 4 | 1uF |
| C12,C13 | C_0805_2012Metric | 2 | 10uf |
| C5,C3,C10 | C_0805_2012Metric | 3 | 22uF |
| C11,C1,C2 | C_0805_2012Metric | 3 | 220uF |
| D1 | LED_0805_2012Metric | 1 | BLUE |
| D2 | LED_0805_2012Metric | 1 | RED |
| D3 | D_SMA | 1 | SMAJ6.0A |
| J1 | PinHeader_2x05_P2.54mm_Vertical | 1 | Bottom |
| J5 | PinHeader_2x05_P2.54mm_Vertical | 1 | Top |
| J2 | USB_C_Receptacle_HRO_TYPE-C-31-M-12 | 1 | USB_C_Receptacle_USB2.0_16P |
| R14,R21 | R_0805_2012Metric | 2 | 0R / Ferrite Bead |
| R2,R5,R1,R4,R3 | R_0805_2012Metric | 5 | 1k |
| R17,R18 | R_0805_2012Metric | 2 | 5.1k |
| R16,R9,R6,R7,R13,R10,R11,R15,R8,R12 | R_0805_2012Metric | 10 | 10k |
| R20,R19 | R_0805_2012Metric | 2 | 47 |
| SW6,SW1,SW2,SW3 | TST-A002_0.6MM_BOSS | 4 | Battery Status, PLAY, VOL+/- |
| SW4 | SLW8645745ARAND | 1 | ON/OFF |
| U1 | BTM308 | 1 | Bluetooth Module |
| U2 | SOIC-8_5.3x5.3mm_P1.27mm | 1 | OPA1678 OP-AMP |
| U3 | PJ-320A | 1 | PJ-320A Audio |
Parts
52| Qty | Value | Footprint | References |
|---|---|---|---|
| 10 | 10k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R6, R7, R8, R9, R10, R11, R12, R13, R15, R16 |
| 5 | 1k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2, R3, R4, R5 |
| 4 | 1uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C6, C7, C8, C9 |
| 3 | 220uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C2, C11 |
| 3 | 22uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C3, C5, C10 |
| 2 | 0 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R14, R21 |
| 2 | 10uf | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C12, C13 |
| 2 | 47 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R19, R20 |
| 2 | 5.1k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R17, R18 |
| 2 | Battery + | Connector_PinHeader_2.54mm:PinHeader_1x01_P2.54mm_Vertical | J3, J6 |
| 2 | Battery - | Connector_PinHeader_2.54mm:PinHeader_1x01_P2.54mm_Vertical | J4, J7 |
| 1 | 100nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4 |
| 1 | BLUE | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1 |
| 1 | Battery Status | TS-A002:TST-A002_0.6MM_BOSS | SW6 |
| 1 | Bluetooth Module | BTM308:BTM308 | U1 |
| 1 | Bottom | Connector_PinHeader_2.54mm:PinHeader_2x05_P2.54mm_Vertical | J1 |
| 1 | ON/OFF | KiCad:SLW8645745ARAND | SW4 |
| 1 | OPA1678 | Package_SO:SOIC-8_5.3x5.3mm_P1.27mm | U2 |
| 1 | PJ-320A | PJ-320A_Library:PJ-320A | U3 |
| 1 | PLAY | TS-A002:TST-A002_0.6MM_BOSS | SW1 |
| 1 | RED | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D2 |
| 1 | SMAJ6.0A | Diode_SMD:D_SMA | D3 |
| 1 | Top | Connector_PinHeader_2.54mm:PinHeader_2x05_P2.54mm_Vertical | J5 |
| 1 | USB_C_Receptacle_USB2.0_16P | Connector_USB:USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J2 |
| 1 | VOL+ | TS-A002:TST-A002_0.6MM_BOSS | SW3 |
| 1 | VOL- | TS-A002:TST-A002_0.6MM_BOSS | SW2 |
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Questions
How big is the BTM308-host PCB?
It measures 52.8 × 40.1 mm and has 4 copper layers, 1.6 mm thick.
What parts does the BTM308-host use?
52 parts, built around the OPA1678ID, PJ-320A and SMAJ6.0A. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the BTM308-host KiCad files?
From the KingJacker/BTM308-bluetooth-module-host repository on GitHub, at the commit this page was made from: the board is BTM308-host/BTM308-host.kicad_pcb and its schematic BTM308-host/BTM308-host.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the BTM308-host design in my own project?
Its repository states no licence, so its author keeps all rights: ask KingJacker before reusing the design.