# Mosfet ## Description Airsoft HPA FCU - 2S VBAT_SOL direct, nRF52 BLE, MOSFET solenoid driver ## Project Details - **Owner:** xkamp - **Created:** 3/10/2026 - **Last Updated:** 3/30/2026 - **Visibility:** Public - **Title:** HPA FCU single-solenoid BLE driver board - **Power Requirements:** 2S Li-ion/LiPo input, VBAT_SOL direct solenoid rail, 3.3V logic buck - **Manufacturing Quantity Target:** Prototype - **Domain:** Embedded - **Connectivity:** BLE - **System Architecture:** flowchart TD BAT["Battery 2S 6.0-8.4V"] INPROT["Input protection\nFuse - reverse polarity - TVS"] VBATSOL["VBAT_SOL rail\nBulk caps"] REG33["3.3V regulator\nBuck low IQ"] MCU["MCU + BLE\nnRF52 module"] TRIG["Trigger input\nRC + Schmitt + ESD"] DRV["Solenoid driver\nN-MOSFET + flyback + clamp"] SENSE["Monitoring\nVBAT ADC + optional current sense"] DBG["SWD + UART\nTest points"] BAT --> INPROT INPROT --> VBATSOL INPROT --> REG33 REG33 --> MCU TRIG --> MCU MCU --> DRV VBATSOL --> DRV DRV --> SOL["Single solenoid"] SENSE --> MCU DBG --> MCU - **Human Interface:** Trigger input (mechanical switch) - **Software:** nRF52 BLE + solenoid timing control - **Reliability Target (MTBF):** High - **Operating Voltage:** 6.0-8.4V ## Key Components ### D1 — [SS34](https://www.flux.ai/lcsc/ss34~6q67.md) - Role Details: Mandatory flyback diode across solenoid - LCSC Part Number: C2758511 - Manufacturer Name: UMW(友台半导体) - Diode Type: Schottky - Part Type: Schottky Barrier Diodes (SBD) - Forward Voltage: 0.3V to 0.45V - Role: Protection - Package or Case Code: SMB_L4.3-W3.6-LS5.4-RD - JLCPCB Part Class: Extended Part - Package: SMA - Reverse Voltage: 40V - Manufacturer Part Number: SS34 **Pins:** - A [pin 2] - K [pin 1] ### D2 — [PESD3V3L1BA-N](https://www.flux.ai/lcsc/pesd3v3l1ba-n~de00.md) - Role: Protection - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1810301031_BORN-PESD3V3L1BA-N_C316020.pdf - Manufacturer Name: BORN(伯恩半导体) - Package: SOD-323 - Reverse Voltage: 3.3V - Product Info Url: https://lcsc.com/product-detail/Others_Bourne-Semicon-Shenzhen-PESD3V3L1BA-N_C316020.html - Role Details: ESD/TVS diode for trigger GPIO line - LCSC Part Number: C316020 - Manufacturer Part Number: PESD3V3L1BA-N - Forward Voltage: 0.9V - Part Type: TVS - Package or Case Code: SOD-323_L1.8-W1.3-LS2.5-BI - JLCPCB Part Class: Extended Part - Diode Type: TVS Diode **Pins:** - 1 [pin 1] - 2 [pin 2] ### D3 — [SMBJ12CA-13-F](https://www.flux.ai/lcsc/smbj12ca-13-f~ofg6.md) - Manufacturer Name: DIODES(美台) - Role: Protection - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Diodes-Incorporated-SMBJ12CA-13-F_C135039.pdf - JLCPCB Part Class: Extended Part - Manufacturer Part Number: SMBJ12CA-13-F - Package or Case Code: SMB_L4.6-W3.6-LS5.3-BI - LCSC Part Number: C135039 - Role Details: VBAT TVS clamp for 2S battery transients (12V standoff) - Package: SMB - Part Type: TVS - Product Info Url: https://lcsc.com/product-detail/TVS_DIODES_SMBJ12CA-13-F_SMBJ12CA-13-F_C135039.html **Pins:** - 1 [pin 1] - 2 [pin 2] ### J1 — [S2B-PH-SM4-TB(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-sm4-tblfsn~b96.md) - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - Part Type: Connector - Role: Connector - Manufacturer Part Number: S2B-PH-SM4-TB(LF)(SN) - Package: SMD - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: JST Sales America Inc. - Role Details: Battery input 2-pin JST-PH 2.0mm right-angle SMD **Pins:** - P1 [pin 1] - P2 [pin 2] ### J2 — [S2B-PH-SM4-TB(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-sm4-tblfsn~b96.md) - Package: SMD - Manufacturer Name: JST Sales America Inc. - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Solenoid output 2-pin JST-PH 2.0mm right-angle SMD (verify current rating for pulsed load) - Manufacturer Part Number: S2B-PH-SM4-TB(LF)(SN) - Part Type: Connector - Role: Connector - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf **Pins:** - P1 [pin 1] - P2 [pin 2] ### Q1 — [DMN3033LDM](https://www.flux.ai/kicad-part-library/dmn3033ldm~58x.md) - Package: SOT-23-6 - Manufacturer Part Number: DMN3033LDM - Role Details: Low-side N-MOSFET for solenoid drive from VBAT_SOL - Role: Switch - Datasheet URL: https://www.diodes.com/assets/Datasheets/ds31345.pdf - Package or Case Code: SOT-23-6 **Pins:** - D [pin 2] - D [pin 5] - D [pin 1] - D [pin 6] - G [pin 3] - S [pin 4] ### TP1 — [5019](https://www.flux.ai/lcsc/5019~mu2j.md) - Part Type: Test Points/Test Rings - Manufacturer Name: Keystone - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5019_Keystone-5019_C238131.html - Role Details: SMD test pad for SWDIO, SWDCLK, NRST, 3V3, GND, UART TX, UART RX - Manufacturer Part Number: 5019 - LCSC Part Number: C238131 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2412030922_Keystone-5019_C238131.pdf - Package: SMD - Package or Case Code: CONN-SMD_5019 - JLCPCB Part Class: Extended Part - Role: Test Point **Pins:** - 1 [pin 1] ### TP2 — [5019](https://www.flux.ai/lcsc/5019~mu2j.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2412030922_Keystone-5019_C238131.pdf - Package or Case Code: CONN-SMD_5019 - JLCPCB Part Class: Extended Part - LCSC Part Number: C238131 - Role Details: SMD test pad for SWDIO, SWDCLK, NRST, 3V3, GND, UART TX, UART RX - Manufacturer Part Number: 5019 - Role: Test Point - Package: SMD - Manufacturer Name: Keystone - Part Type: Test Points/Test Rings - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5019_Keystone-5019_C238131.html **Pins:** - 1 [pin 1] ### TP3 — [5019](https://www.flux.ai/lcsc/5019~mu2j.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2412030922_Keystone-5019_C238131.pdf - Package or Case Code: CONN-SMD_5019 - JLCPCB Part Class: Extended Part - LCSC Part Number: C238131 - Manufacturer Part Number: 5019 - Package: SMD - Role Details: SMD test pad for SWDIO, SWDCLK, NRST, 3V3, GND, UART TX, UART RX - Manufacturer Name: Keystone - Part Type: Test Points/Test Rings - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5019_Keystone-5019_C238131.html - Role: Test Point **Pins:** - 1 [pin 1] ### TP4 — [5019](https://www.flux.ai/lcsc/5019~mu2j.md) - Role Details: SMD test pad for SWDIO, SWDCLK, NRST, 3V3, GND, UART TX, UART RX - Role: Test Point - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5019_Keystone-5019_C238131.html - Part Type: Test Points/Test Rings - Manufacturer Name: Keystone - LCSC Part Number: C238131 - Package: SMD - JLCPCB Part Class: Extended Part - Package or Case Code: CONN-SMD_5019 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2412030922_Keystone-5019_C238131.pdf - Manufacturer Part Number: 5019 **Pins:** - 1 [pin 1] ### TP5 — [5019](https://www.flux.ai/lcsc/5019~mu2j.md) - Manufacturer Part Number: 5019 - Role Details: SMD test pad for SWDIO, SWDCLK, NRST, 3V3, GND, UART TX, UART RX - JLCPCB Part Class: Extended Part - Package or Case Code: CONN-SMD_5019 - Role: Test Point - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2412030922_Keystone-5019_C238131.pdf - LCSC Part Number: C238131 - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5019_Keystone-5019_C238131.html - Part Type: Test Points/Test Rings - Manufacturer Name: Keystone - Package: SMD **Pins:** - 1 [pin 1] ### TP6 — [5019](https://www.flux.ai/lcsc/5019~mu2j.md) - Role Details: SMD test pad for SWDIO, SWDCLK, NRST, 3V3, GND, UART TX, UART RX - Manufacturer Name: Keystone - Part Type: Test Points/Test Rings - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5019_Keystone-5019_C238131.html - Role: Test Point - Manufacturer Part Number: 5019 - LCSC Part Number: C238131 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2412030922_Keystone-5019_C238131.pdf - JLCPCB Part Class: Extended Part - Package or Case Code: CONN-SMD_5019 - Package: SMD **Pins:** - 1 [pin 1] ### TP7 — [5019](https://www.flux.ai/lcsc/5019~mu2j.md) - JLCPCB Part Class: Extended Part - Package or Case Code: CONN-SMD_5019 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2412030922_Keystone-5019_C238131.pdf - Package: SMD - LCSC Part Number: C238131 - Manufacturer Part Number: 5019 - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5019_Keystone-5019_C238131.html - Manufacturer Name: Keystone - Part Type: Test Points/Test Rings - Role Details: SMD test pad for SWDIO, SWDCLK, NRST, 3V3, GND, UART TX, UART RX - Role: Test Point **Pins:** - 1 [pin 1] ### U1 — [NB680GD-P](https://www.flux.ai/monolithicpower/nb680gd-p~ie.md) - Manufacturer Part Number: NB680GD-P - Manufacturer Name: Monolithic Power Systems - Package or Case Code: QFN-12_NB680_MNP - Datasheet URL: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/NB680 - Role Details: 3.3V synchronous buck from VBAT (6.0-8.4V) for logic rail - Package: QFN-12 - Role: Regulator - Product Image Url: https://www.monolithicpower.com/pub/media/catalog/product/N/B/NB680_1043_1.jpg - Product Info Url: https://www.monolithicpower.com/en/catalog/product/view/id/1043?utm_source=ultralibrarian&utm_medium=component_search&utm_campaign=listing **Pins:** - AGND [pin 10] - BST [pin 8] - CLK [pin 4] - EN [pin 11] - ENCLK [pin 12] - LDO [pin 6] - PG [pin 3] - PGND [pin 2] - SW [pin 7] - VCC [pin 9] - VIN [pin 1] - VOUT [pin 5] ### U2 — [MDBT50Q-U1MV2](https://www.flux.ai/vasyl/mdbt50q-u1mv2~zyl.md) - Package or Case Code: XCVR_MDBT50Q-1MV2 - Package: Module - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: RF module - Datasheet URL: https://www.raytac.com/download/index.php?index_id=43 - Role: MCU - Manufacturer Part Number: MDBT50Q-U1MV2 - Role Details: nRF52840 BLE module for configuration and telemetry - Manufacturer Name: Raytac Cororation **Pins:** - D- [pin 34] - D+ [pin 35] - GND [pin 55] - GND [pin 1] - GND [pin 33] - GND [pin 15] - GND [pin 2] - NC [pin 31] - NC [pin 45] - NC [pin 49] - NC [pin 4] - NC [pin 60] - NC [pin 59] - NC [pin 42] - P0.00 [pin 17] - P0.01 [pin 18] - P0.02 [pin 11] - P0.03 [pin 9] - P0.04 [pin 20] - P0.05 [pin 21] - P0.06 [pin 22] - P0.07 [pin 23] - P0.08 [pin 24] - P0.09 [pin 52] - P0.10 [pin 54] - P0.11 [pin 27] - P0.12 [pin 29] - P0.13 [pin 37] - P0.14 [pin 36] - P0.15 [pin 39] - P0.16 [pin 38] - P0.17 [pin 41] - P0.18/NRST [pin 40] - P0.19 [pin 8] - P0.20 [pin 44] - P0.21 [pin 43] - P0.22 [pin 46] - P0.23 [pin 5] - P0.24 [pin 48] - P0.25 [pin 3] - P0.26 [pin 19] - P0.27 [pin 16] - P0.28 [pin 13] - P0.29 [pin 10] - P0.30 [pin 14] - P0.31 [pin 12] - P1.00 [pin 47] - P1.01 [pin 61] - P1.02 [pin 50] - P1.03 [pin 7] - P1.04 [pin 56] - P1.05 [pin 6] - P1.06 [pin 57] - P1.07 [pin 58] - P1.08 [pin 25] - P1.09 [pin 26] - SWDCLK [pin 53] - SWDIO [pin 51] - VBUS [pin 32] - VDD [pin 28] - VDDH [pin 30] ### U3 — [74LVC1G17SE-7](https://www.flux.ai/lcsc/74lvc1g17se-7~m79.md) - Role: Conditioning - LCSC Part Number: C212314 - Manufacturer Name: DIODES(美台) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Diodes-Incorporated-74LVC1G17SE-7_C212314.pdf - JLCPCB Part Class: Extended Part - Manufacturer Part Number: 74LVC1G17SE-7 - Package: SOT-353 - Package or Case Code: SOT-353_L2.2-W1.4-P0.65-LS2.4-BL - Role Details: Schmitt buffer for trigger input (cleans RC filtered signal) - Product Info Url: https://lcsc.com/product-detail/74-Series_Diodes-Incorporated_74LVC1G17SE-7_Diodes-Incorporated-74LVC1G17SE-7_C212314.html - Part Type: Buffers / Drivers **Pins:** - A [pin 2] - GND [pin 3] - NC [pin 1] - VCC [pin 5] - Y [pin 4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/xkamp/mosfet~8m](https://www.flux.ai/xkamp/mosfet~8m).* --- *Generated from [https://www.flux.ai/xkamp/mosfet~8m](https://www.flux.ai/xkamp/mosfet~8m)*