4 layers194 × 94 mm
4 layers172 × 140.5 mm
Bottom board
mod-audio/mod-hw-duoX1Hardware project of MOD Duo X
- Size
- 172 × 140.5 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 403
- Nets
- 416
- Pads
- 1,358
- Tracks, vias
- 4,184, 498
- Pours
- 14
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 13 Nov 2014
- Updated
- 3 Nov 2026
Overview
Bottom board is an open-source printed circuit board by mod-audio, from the mod-audio/mod-hw-duoX repository on GitHub. It is a 4-layer board of 172 × 140.5 mm with 403 parts on 416 nets, routed with 4,184 tracks and 498 vias.
It is built around the 74LVC3G17DP, ISL83491IBZ and CS4265-CNZ, with the LM2596S-5.0, LM358 and LM4562NA among its other parts. Its parts include 151 resistors, 98 capacitors, 26 diodes, 17 ICs and 14 transistors.
Main components
12
74LVC3G17DP
TSSOP-8-40℃~+125℃ 1 1.65V~5.5V 3 3.6ns@3.3V,50pF 32mA 32mA 4uA 74LVC Schmitt trigger Unidirectional TSSOP-8 Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers
ISL83491IBZ
SOIC-14-40℃~+85℃ 1 1 10Mbps 3V~3.6V Transceiver SOIC-14 RS-485 / RS-422 ICs ROHSRenesas ElectronicsRS-485/RS-422 ICsCS4265-CNZ
QFN-32(5x5)-10℃~+70℃ 3.13V~5.25V、3.13V~5.25V 4kHz~192kHz Encoder/decoder On-chip digital gain、Mute control、Master-slave clock negotiation Serial QFN-32(5x5) Audio Interface ICs ROHSCirrus LogicAudio Interface ICs
LM2596S-5.0
TO-263-5-40℃~+125℃@(TJ) 1 150kHz 3A 4.5V~40V 5V 5mA Buck Buck Built-in Fixed No TO-263-5 DC-DC Converters ROHSTexas InstrumentsDC-DC Converters
LM358
SOP-8-18V~18V 0℃~+70℃ 1.2MHz 10nA 2 24mA 3V~36V 500uA 50nA 5mV 80dB Built-in compensation SOP-8 Operational Amplifier ROHSMSKSEMIOperational Amplifier
LM4562NA
PDIP-8-17V~-2.5V、2.5V~17V -40℃~+85℃ 0.00003% 10mA 120dB 2-Channel PDIP-8 Audio Amplifiers ROHSTexas InstrumentsAudio Amplifiers
DG9426EDQ-T1-GE3
TSSOP-16-40℃~+85℃ -8V~-3V、3V~16V、3V~8V 1.6Ω 1:1 20ns 36ns 4 44ns 89pF TSSOP-16 Analog Switches, Multiplexers ROHSVishay IntertechnologyAnalog Switches, Multiplexers
LD1117S50TR(MS)
SOT-223-20℃~+125℃@(Ta) 1 1.4V@(1A) 12V 1A 2mA 4.9V~5.1V Fixed Positive Thermal Shutdown SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSMSKSEMIVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
6N136S
SMD-8P-40℃~+100℃ 1 1.45V 19% 1Mbit/s 1kV/us 20V 20mA 25mA 4.5V~18V 5V 5kV 800ns 800ns 8mA DC SMD-8P Logic Output Optoisolators ROHSAOTELogic Output Optoisolators
AP2120N-3.3TRG1
SOT-23-40℃~+85℃@(Tj) 1 150mA 200mV@(100mA) 25uA 3.3V 30uVrms 65dB@(1kHz) 6V Fixed Over Current Protection Positive SOT-23 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSDiodes IncorporatedVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
AT24CS08-STUM-T
SOT-23-5-40℃~+85℃ 1,000,000 cycles 1.7V~5.5V 100 Years 1MHz 5ms 8Kbit Hardware write protection function、Noise suppression function、Built-in power-on reset (POR) I2C SOT-23-5 EEPROM ROHSMicrochip TechnologyEEPROM
RR0816P-103-D
0603-55℃~+125℃ 10kΩ 63mW Thin Film Resistor ±0.5% ±25ppm/℃ 0603 Chip Resistor - Surface Mount ROHSSusumuChip Resistor - Surface Mount
README
README.mdmod-hw-duoX
This repository contains the schematics and PCB design files for the MOD Duo X.
The MOD DuoX bottom-board is done in Kicad 5. The other board (controller board) is done in Altium.
Please, use KiCAD 5 to edit the project.
The master branch has the most recent version of the bottom-board project, made for the Duo X.
The rev_20161129-updated branch has the legacy production version of the MOD Duo boards.
License
Copyright (c) 2014-2026 MOD Audio Limited.
The hardware design files (schematics, PCB layouts, fabrication files, BOMs) are licensed under
CC BY-NC-SA 4.0 (see LICENSE).
You may study, modify, repair and build them for yourself, and share your changes under the same licence.
You may not use them commercially, for example to make or sell boards or devices.
Third-party files (manufacturer component models, symbols and footprints, module documentation) are not covered by
this licence. See NOTICE for the list.
The MOD logo is a registered trademark (EU trade mark no. 016228827; UK trade mark no. UK00916228827).
The licence gives no right to use the MOD name or logo. See NOTICE.
For commercial licensing, contact MOD Audio.
Parts
403| Qty | Value | Footprint | References |
|---|---|---|---|
| 53 | 100nF | Capacitor_SMD:C_0603_1608Metric | C2, C11, C12, C14, C17, C18, C20, C21, C22, C24, C25, C28, C30, C32, C36, C37 +37 |
| 43 | 10K | Resistor_SMD:R_0603_1608Metric | R1, R107, R108, R109, R110, R111, R112, R113, R114, R115, R116, R117, R118, R119, R120, R133 +27 |
| 19 | 10uF | Capacitor_SMD:C_0805_2012Metric | C10, C13, C16, C19, C26, C27, C29, C31, C34, C35, C38, C59, C60, C63, C66, C69 +3 |
| 16 | TestPoint | TestPoint:TestPoint_Pad_D1.0mm | TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP14, TP15, TP16, TP20, TP21 |
| 14 | 1M | Resistor_SMD:R_0603_1608Metric | R18, R57, R60, R61, R69, R70, R78, R81, R82, R83, R93, R94, R95, R96 |
| 12 | 100pF | Capacitor_SMD:C_0603_1608Metric | CA3, CA5, CA7, CA9, CA13, CA14, CA18, CA23, CA24, CA28, CA29, CA30 |
| 12 | 22R | Resistor_SMD:R_0603_1608Metric | R9, R10, R11, R12, R13, R14, R15, R19, R26, R27, R37, R38 |
| 11 | 2K7 | Resistor_SMD:R_0603_1608Metric | R6, R7, R8, R20, R21, R22, R23, R65, R66, R67, R68 |
| 11 | BAT54S | Package_TO_SOT_SMD:SOT-23 | D3, D4, D5, D6, D14, D15, D22, D23, D24, D25, D28 |
| 10 | 10uF | Capacitor_SMD:CP_Elec_4x5.7 | CA6, CA10, CA11, CA12, CA15, CA19, CA20, CA25, CA26, CA27 |
| 10 | 1N4148 | Diode_SMD:D_SOD-323 | D7, D8, D11, D12, D13, D16, D17, D18, D19, D20 |
| 10 | 22uF | Capacitor_SMD:C_0805_2012Metric | C8, C33, C53, C54, C78, C86, C88, C90, C92, C94 |
| 8 | 150R | Resistor_SMD:R_0603_1608Metric | R121, R122, R123, R124, R125, R126, R127, R128 |
| 8 | 2N7002 | Package_TO_SOT_SMD:SOT-23 | Q1, Q2, Q3, Q4, Q9, Q12, Q13, Q16 |
| 7 | 100K | Resistor_SMD:R_0603_1608Metric | R5, R28, R58, R59, R62, R84, R86 |
| 7 | 1K | Resistor_SMD:R_0603_1608Metric | R17, R41, R54, R63, R64, R143, R144 |
| 6 | J110 | Package_TO_SOT_SMD:SOT-23 | Q8, Q10, Q11, Q14, Q15, Q17 |
| 6 | NYS215 | footprints:NMJ6HCD2 | J7, J8, J9, J10, J16, J17 |
| 5 | 56K | Resistor_SMD:R_0603_1608Metric | R42, R53, R71, R72, R85 |
| 5 | HOLE | MountingHole:MountingHole_3.5mm | H1, H2, H3, H4, H5 |
| 4 | 0R | Resistor_SMD:R_0603_1608Metric | R147, R148, R149, R150 |
| 4 | 100R | Resistor_SMD:R_0603_1608Metric | R47, R105, R106, RA38 |
| 4 | 1uF | Capacitor_SMD:C_0603_1608Metric | C15, C62, C67, C77 |
| 4 | 47uF | Capacitor_SMD:CP_Elec_6.3x7.7 | CA17, CA31, CA32, CA33 |
| 4 | 4K7 | Resistor_SMD:R_0603_1608Metric | R101, R102, R103, R104 |
| 4 | 56R | Resistor_SMD:R_0603_1608Metric | R43, R44, R45, R46 |
| 3 | 100uF | Capacitor_SMD:CP_Elec_6.3x7.7 | CA16, CA21, CA22 |
| 3 | 15K | Resistor_SMD:R_0603_1608Metric | R30, R89, R90 |
| 3 | 220K | Resistor_SMD:R_0603_1608Metric | R74, R75, R87 |
| 3 | 220R | Resistor_SMD:R_0603_1608Metric | R32, R33, R34 |
| 3 | 47K | Resistor_SMD:R_0603_1608Metric | R76, R77, R88 |
| 3 | 47uF | Capacitor_SMD:CP_Elec_5x5.4 | C6, C9, C23 |
| 3 | FIDUCIAL | footprints:fiducial_in-circuit | FID1, FID2, FID3 |
| 3 | Ferrite_Bead | Resistor_SMD:R_0603_1608Metric | FB1, FB2, FB3 |
| 3 | LM833DR2G | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U11, U12, U22 |
| 2 | 1000uF | Capacitor_SMD:CP_Elec_10x10.5 | C1, C3 |
| 2 | 1nF | Capacitor_SMD:C_0603_1608Metric | C5, C44 |
| 2 | 1uF | Capacitor_SMD:C_1210_3225Metric | CA4, CA8 |
| 2 | 2.2nF | Capacitor_SMD:C_0603_1608Metric | CA1, CA2 |
| 2 | 22K | Resistor_SMD:R_0603_1608Metric | R99, R100 |
| 2 | 33nF | Capacitor_SMD:C_0603_1608Metric | C73, C74 |
| 2 | 47R | Resistor_SMD:R_0603_1608Metric | R91, R92 |
| 2 | 499K | Resistor_SMD:R_0603_1608Metric | R141, R142 |
| 2 | 5K6 | Resistor_SMD:R_0603_1608Metric | R97, R98 |
| 2 | 6R8 | Resistor_SMD:R_0603_1608Metric | R131, R132 |
| 2 | 75K | Resistor_SMD:R_0603_1608Metric | R129, R130 |
| 2 | DG9426E | Package_SO:TSSOP-16_4.4x5mm_P0.65mm | U9, U13 |
| 2 | DIN_5 | footprints:SDS-50J | J13, J14 |
| 2 | G6S-2 | footprints:Relay_DPDT_Omron_G6S-2F | K1, K2 |
| 2 | HOLE | MountingHole:MountingHole_2.7mm | H8, H9 |
| 2 | LD1117S50TR | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U2, U4 |
| 2 | PRTR5V0U2X | Package_TO_SOT_SMD:SOT-143 | D9, D10 |
| 2 | RSX205 | Diode_SMD:D_SOD-123F | D1, D2 |
| 2 | Standoff | MountingHole:MountingHole_3.2mm_M3_DIN965_Pad | H6, H7 |
| 2 | TestPoint | TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded | TP18, TP22 |
| 1 | 107R | Resistor_SMD:R_0603_1608Metric | R56 |
| 1 | 10R | Resistor_SMD:R_0603_1608Metric | R16 |
| 1 | 10nF | Capacitor_SMD:C_0603_1608Metric | C84 |
| 1 | 1K5 | Resistor_SMD:R_0603_1608Metric | R73 |
| 1 | 1mH | Inductor_SMD:L_Bourns_SRR1260 | L1 |
| 1 | 22pF | Capacitor_SMD:C_0603_1608Metric | C85 |
| 1 | 24.576MHz | Oscillator:Oscillator_SMD_Abracon_ASV-4Pin_7.0x5.1mm | X1 |
| 1 | 243R | Resistor_SMD:R_0603_1608Metric | R55 |
| 1 | 470uF | Capacitor_SMD:CP_Elec_8x10.5 | C43 |
| 1 | 47UH 2A 135 MOHM | Uno:SRN8040TA | L2 |
| 1 | 6N136S | Package_DIP:SMDIP-8_W9.53mm | U17 |
| 1 | 74LVC3G17 | Package_SO:VSSOP-8_2.3x2mm_P0.5mm | U3 |
| 1 | ADC122S021 | Package_SO:VSSOP-8_3.0x3.0mm_P0.65mm | U20 |
| 1 | AP2120N-3.3 | Package_TO_SOT_SMD:SOT-23 | U5 |
| 1 | AS0A823-H4SB-7H | Uno:TE_2309409-1 | J3 |
| 1 | AT24CS08 | Package_TO_SOT_SMD:SOT-23-5 | U7 |
| 1 | CS4265 | Package_DFN_QFN:QFN-32-1EP_5x5mm_P0.5mm_EP3.1x3.1mm | U6 |
| 1 | Conn_01x25 | F51L-1A7H1-11024:F51L-1A7H1-11024 | J2 |
| 1 | D_Schottky-Device | Diode_SMD:D_MELF | D21 |
| 1 | Fuse 2A | footprints:Fuse_2920_0ZCF_Bel | F1 |
| 1 | ISL83086E | Package_SO:SOIC-14_3.9x8.7mm_P1.27mm | U18 |
| 1 | Jumper | Jumper:SolderJumper-2_P1.3mm_Bridged2Bar_RoundedPad1.0x1.5mm | JP1 |
| 1 | LM2596S-5 | Package_TO_SOT_SMD:TO-263-5_TabPin3 | U15 |
| 1 | LM358 | Package_SO:TSSOP-8_3x3mm_P0.65mm | U10 |
| 1 | LM4562 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U8 |
The 389 most common of 403 parts.
Questions
How big is the Bottom board PCB?
It measures 172 × 140.5 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Bottom board use?
403 parts, built around the 74LVC3G17DP, ISL83491IBZ, CS4265-CNZ and LM2596S-5.0. 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 Bottom board KiCad files?
From the mod-audio/mod-hw-duoX repository on GitHub, at the commit this page was made from: the board is hw-design/bottom-board/PCB Source/bottom-board.kicad_pcb and its schematic hw-design/bottom-board/PCB Source/audio-codec.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Bottom board design in my own project?
Its repository states no licence, so its author keeps all rights: ask mod-audio before reusing the design.
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