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Main chips

Assembly

Standard assembly will be used over economic assembly. The primary reason is that the BNO055 and BMP388 aren't available with economic assembly. The number of extended parts on the board is exactly half of all unique components on the board, therefore the loading fee is equal either way.

Point of Load vs Bus Regulation

Point of load regulation is where your power bus is lets say 7.4 volts, and all your chips are 5v so you regulate the voltage near each chip. Bus regulation would be having the bus 5v.

Point of load means having regulators on each module, but inherently less stability. If you can get away without having to do point of load regulation you could save a lot of money though.

To reduce costs, both the 5v and the 3.3v regulators will be deleted from the modules, in favour of regulated bus power. Before the full power module is ready however, we will need a very power module that supplies 5v and 3.3v.

$375 can be saved buy not doing point of load. Delete the two regs and mux, that gets rid of 5 extended JLCPCB parts. It costs $3 per extended part (actually it's about 2.21). The minimum order number is 5. There will be 5 modules. 5 * 3 * 5 * 5 = 375.

Impedance matching

This guide was used to do the impedance matching. The KiCad calculator and the JLCPCB design rules were used.

BOM

Current KiCad bom

Reference info Value Footprint LCSC Part # JLC Link Digikey Link basic? price Current Draw Qty DNP
Y2 CAN Clock X322516MLB4SI X322516MLB4SI:OSC_X322516MLB4SI C12668 https://jlcpcb.com/partdetail/Yxc_CrystalOscillators-X322516MOB4SI/C12668 nan no C$0.0829 200 uW 3.3v 1 nan
Y1 BNO055 Crystal ABS07-32.768KHZ-T ABS07-32.768KHZ-T:XTAL_ABS07-32.768KHZ-T C130253 https://jlcpcb.com/partdetail/AbraconLlc-ABS07_32_768KHZT/C130253 nan no C$0.6839 0.5 uW 3.3v 1 nan
X1 MCU Crystal ABM8-272-T3 ABM8-272-T3:ABM8-272-T3_ABR C20625731 https://jlcpcb.com/partdetail/AbraconLlc-ABM8_272T3/C20625731 nan no C$0.6692 200 uW 3.3v 1 nan
U9 CAN Controller/Tranceiver MCP25625T-E/ML MCP25625T_E_ML:QFN28_6X6MC_MCH C191253 https://jlcpcb.com/partdetail/MicrochipTech-MCP25625T_EML/C191253 nan no C$2.9424 Con=10mA, Tra=70mA 1 nan
U8 BNO055 BNO055 Package_LGA:LGA-28_5.2x3.8mm_P0.5mm C93216 https://jlcpcb.com/partdetail/BoschSensortec-BNO055/C93216 nan no C$14.0435 12.3mA 1 nan
U5 BMP388 BMP388 BMP388:PQFN50P200X200X80-10N C779278 https://jlcpcb.com/partdetail/BoschSensortec-BMP388/C779278 nan no C$2.3423 800uA 1 nan
U4 Flash W25Q128JVP Package_SON:WSON-8-1EP_6x5mm_P1.27mm_EP3.4x4.3mm C190862 https://jlcpcb.com/partdetail/WinbondElec-W25Q128JVPIQ/C190862 nan no C$1.0737 25mA 1 nan
U2 MCU RP2040 Package_DFN_QFN:QFN-56-1EP_7x7mm_P0.4mm_EP3.2x3.2mm C2040 https://jlcpcb.com/partdetail/RaspberryPi-RP2040/C2040 nan no C$1.4190 20mA 1 nan
S1,S2 Button TS-1187A-B-A-B TS-1187A-B-A-B:SW_TS-1187A-B-A-B C318884 https://jlcpcb.com/partdetail/XKBConnection-TS_1187A_B_AB/C318884 nan yes C$0.0242 nan 2 nan
R83,R87,R91 10k ohm 10k Resistor_SMD:R_0402_1005Metric C25744 https://jlcpcb.com/partdetail/26487-0402WGF1002TCE/C25744 nan yes C$0.0007 nan 3 nan
R220,R221,R222,R223 4.7k ohm 4.7k Resistor_SMD:R_0402_1005Metric C25900 https://jlcpcb.com/partdetail/26643-0402WGF4701TCE/C25900 nan yes C$0.0007 nan 4 nan
R203,R204 27 ohm 27 Resistor_SMD:R_0402_1005Metric C25100 https://jlcpcb.com/partdetail/25843-0402WGF270JTCE/C25100 nan no C$0.0007 nan 2 nan
R12,R30 1k ohm 1k Resistor_SMD:R_0402_1005Metric C11702 https://jlcpcb.com/partdetail/12256-0402WGF1001TCE/C11702 nan yes C$0.0007 nan 2 nan
R89 150 ohm 150 Resistor_SMD:R_0603_1608Metric C22808 https://jlcpcb.com/partdetail/23535-0603WAF1500T5E/C22808 nan yes C$0.0013 nan 1 nan
J6 USB-C USB_C_Receptacle_USB2.0_16P Connector_USB:USB_C_Receptacle_Palconn_UTC16-G C2765186 https://jlcpcb.com/partdetail/ShouHan-TYPE_C_16PIN_2MD_073/C2765186 nan no C$0.0738 nan 1 nan
J4 two headders Conn_01x02 Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical nan nan nan nan nan nan 1 DNP
J1 PCIe fingers Bus_PCI_Express_x1 Connector_PCBEdge:BUS_PCIexpress_x1 nan nan nan nan nan nan 1 DNP
D88 Red LED LED LED_SMD:LED_0603_1608Metric C2286 https://jlcpcb.com/partdetail/Hubei_KentoElec-KT0603R/C2286 nan yes C$0.0075 nan 1 nan
C85,C86,C94,C95 22pF Cap 22p Capacitor_SMD:C_0402_1005Metric C1555 https://jlcpcb.com/partdetail/1907-0402CG220J500NT/C1555 nan yes C$0.0077 nan 4 nan
C84,C208,C210 1uF Cap 1u Capacitor_SMD:C_0402_1005Metric C52923 https://jlcpcb.com/partdetail/53938-CL05A105KA5NQNC/C52923 nan yes C$0.0041 nan 3 nan
C40,C50,C51,C81,C82,C90,C92,C93,C206,C207,C209,C211,C212,C213,C214,C215,C216 100nF Cap 100n Capacitor_SMD:C_0402_1005Metric C307331 https://jlcpcb.com/partdetail/291005-CL05B104KB54PNC/C307331 nan yes C$0.0077 nan 17 nan
C10,C11 15pF Cap 15p Capacitor_SMD:C_0402_1005Metric C1548 https://jlcpcb.com/partdetail/1900-0402CG150J500NT/C1548 nan yes C$0.0013 nan 2 nan