2 layers200.7 × 149.9 mm
2 layers185.4 × 102.9 mm
Isa FDC CF USB
TheDuck0s/isa_FDC-CF-USBISA 8-bit Floppy, XT-CF(v4) and USB card
- Size
- 185.4 × 102.9 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 76
- Nets
- 192
- Pads
- 647
- Tracks, vias
- 5,926, 208
- Pours
- 961
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 11 Jul 2026
- Updated
- 17 Oct 2026
Overview
Isa FDC CF USB is an open-source printed circuit board by TheDuck0s, from the TheDuck0s/isa_FDC-CF-USB repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 185.4 × 102.9 mm with 76 parts on 192 nets, routed with 5,926 tracks and 208 vias.
It is built around the 74HC245D, 74LS32SC and 74LS04PC, with the USBLC6-2P6 among its other parts. Its parts include 29 capacitors, 15 ICs, 8 resistors, 5 switches and 3 connectors.
Main components
4
74HC245D
SO-20-300mil-40℃~+125℃ 1 160uA 2V~6V 7.8mA 7.8mA 74HC 8 9ns@4.5V,50pF Bidirectional Tri-State SOIC-20-300mil Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers
74LS32SC
-- Logic Gates ROHSTexas InstrumentsLogic Gates
74LS04PC
PDIP-140℃~+70℃ 4.75V~5.25V 6 6.6mA 74LS PDIP-14 InvertersonsemiInverters
USBLC6-2P6
SOT-666-6-40℃~+125℃ 150nA 17V 2 3.5pF 5.25V 5A@8/20us 6V ESD IEC 61000-4-2 Unidirectional SOT-666-6 ESD and Surge Protection (TVS/ESD) ROHSSTMicroelectronicsESD And Surge Protection (TVS/ESD)
README
README.mdISA FDC, XT-CF, USB Card
This is an IBM XT-compatible FDC, XT-CF-Lite and USB card, based on a design (FDC & XT-CF-Lite-V4) by Sergey Kiselev.
The Idea
The goal of this project is to create an XT-compatible computer on a passive backplane with a modular card-based architecture, minimizing the overall footprint while providing support for all common expansion cards.
Hardware Documentation
Schematic PDF: Schematic - Version 1.0
PCB PDF: Board Design - Version 1.0
Gerber Files: Gerber- Version 1.0
Bill of Materials
coming soon...
Release Notes
Changes:
Version 1.0
- Initial Release
Benchmarks
Checkit 3.0 Benchmark:
@9.55 MHz
- XT-CF: 725KB/s
Final Note
- The card is tested and works.
- This card won't fit Sergey's case (this one). The case will need to be enlarged.
- Card size 185.3 mm x 102.9 mm
Parts
76| Qty | Value | Footprint | References |
|---|---|---|---|
| 13 | 0.1uF | My_Components:Cap_Cer_508 | C1, C6, C7, C8, C9, C10, C11, C12, C13, C14, C18, C24, C29 |
| 4 | 0.1uF | Cap_Cer_504 | C2, C3, C4, C5 |
| 4 | 10uF | My_Components:Cap_Tant_508 | C22, C23, C27, C28 |
| 4 | 22pF | My_Components:Cap_Cer_508 | C19, C20, C25, C26 |
| 2 | 10kΩ | My_Components:Conn_SIL9 | RR2, RR4 |
| 2 | 1kΩ | My_Components:Res_762 | R6, R7 |
| 2 | 22pF | Cap_Cer_504 | C15, C16 |
| 2 | 74ALS138 | DIP16_300 | U4, U5 |
| 2 | 74LS32 | Package_DIP:DIP-14_W7.62mm | U10, U14 |
| 2 | 74LS688 | My_Components:IC_DIP20_300 | U7, U8 |
| 2 | CONN_1 | HOLE_3MM | HOLE1, HOLE2 |
| 1 | 0.01uF | My_Components:Cap_Cer_508 | C21 |
| 1 | 1.1A | My_Components:Cap_Cer_508 | F1 |
| 1 | 10k | My_Components:Res_762 | R4 |
| 1 | 10k | My_Components:Conn_SIL5 | RR3 |
| 1 | 12MHz | My_Components:Crystal_HC-49U_Vert | X2 |
| 1 | 1k | My_Components:Conn_SIL6 | RR1 |
| 1 | 1k | My_Components:Res_762 | R5 |
| 1 | 24MHz | Crystal_HC-49U_Vert | X1 |
| 1 | 28C64 | DIP28_600 | U2 |
| 1 | 28C64 | My_Components:IC_DIP28_600 | U6 |
| 1 | 2N7000 | Package_TO_SOT_THT:TO-92 | Q1 |
| 1 | 330Ω | My_Components:Res_762 | R2 |
| 1 | 4.7nF | Cap_Cer_504 | C17 |
| 1 | 470 | My_Components:Res_762 | R1 |
| 1 | 470Ω | My_Components:Res_762 | R8 |
| 1 | 5.6k | My_Components:Res_762 | R3 |
| 1 | 74ALS138 | Package_DIP:DIP-16_W7.62mm | U13 |
| 1 | 74HC245 | Package_DIP:DIP-20_W7.62mm | U12 |
| 1 | 74LS04 | Package_DIP:DIP-14_W7.62mm | U9 |
| 1 | 74LS688 | DIP20_300 | U3 |
| 1 | 82077AA | PLCC68_TH | U1 |
| 1 | CF_CARD | My_Components:Conn_CF_N7E50-Q516XX-40 | P2 |
| 1 | CH375 | Package_SO:SOP-28_8.4x18.16mm_P1.27mm | U11 |
| 1 | FDC_CFG | My_Components:Switch_DIP_7_Positions | SW1 |
| 1 | FILTER | My_Components:Res_1016 | FB1 |
| 1 | FLOPPY | My_Components:Conn_Pin_Header_17x2_2.54mm_Shrouded | P1 |
| 1 | LED_USB | My_Components:Conn_Pin_Header_2x1_2.54mm | JP3 |
| 1 | LED_XTCF | My_Components:Conn_Pin_Header_2x1_2.54mm | JP2 |
| 1 | PCB Edge Connector | Conn_Bus_ISA8 | BUS1 |
| 1 | PS/2 FLOPPY | Conn_Pin_Header_2x1_Nokey | JP1 |
| 1 | PWR_LED | My_Components:LED_3mm | D1 |
| 1 | USBLC6-2P6 | Package_TO_SOT_SMD:SOT-23-6 | U15 |
| 1 | USB_A | My_Components:Conn_Pin_Header_5x1_2.54mm | P3 |
| 1 | USB_CFG | My_Components:Switch_DIP_4_Positions | SW4 |
| 1 | USB_IRQ | My_Components:Switch_DIP_5_Positions | SW5 |
| 1 | XTCF_CFG | My_Components:Switch_DIP_7_Positions | SW3 |
| 1 | XTCF_CS | My_Components:Switch_DIP_3_Positions | SW2 |
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Questions
How big is the Isa FDC CF USB PCB?
It measures 185.4 × 102.9 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Isa FDC CF USB use?
76 parts, built around the 74HC245D, 74LS32SC, 74LS04PC and USBLC6-2P6. 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 Isa FDC CF USB KiCad files?
From the TheDuck0s/isa_FDC-CF-USB repository on GitHub, at the commit this page was made from: the board is Kicad/isa_FDC-CF-USB.kicad_pcb and its schematic Kicad/isa_FDC-CF-USB.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Isa FDC CF USB design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).