4 layers243.8 × 170.2 mm
2 layers83.8 × 61.5 mm
SegaCD Ramcart
WindDrake/SegaCD_Ramcart28Sega Genesis/Megadrive CD Back-up RAM Cart
- Size
- 83.8 × 61.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 22
- Nets
- 82
- Pads
- 215
- Tracks, vias
- 867, 153
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 20 Aug 2021
- Updated
- 14 Dec 2025
Overview
SegaCD Ramcart is an open-source printed circuit board by WindDrake, from the WindDrake/SegaCD_Ramcart repository on GitHub. It is a 2-layer board of 83.8 × 61.5 mm with 22 parts on 82 nets, routed with 867 tracks and 153 vias.
It is built around the 74LS245SC, 74LS30PC and 74LS32SC, with the 74LS74PC, IS61C5128AS-25QLI and MMBD1204 among its other parts. Its parts include 8 capacitors, 7 ICs, 2 resistors, 1 diode and 1 connector.
Main components
674LS245SC
-0℃~+70℃ 12ns@5V,45pF 15mA 24mA 4.75V~5.25V 74LS 8 Bidirectional Output enable Schmitt trigger Tri-State - Buffers, Drivers, Receivers, Transceivers ROHSTexas InstrumentsBuffers, Drivers, Receivers, Transceivers
74LS30PC
PDIP-140℃~+70℃ 1 1.1mA 18ns@5V,50pF、20ns@5V,50pF 2.7V 2V 4.75V~5.25V 400uA 500mV 74LS Series 8 800mV 8mA NAND Gate PDIP-14 Logic GatesTexas InstrumentsLogic Gates
74LS32SC
-- Logic Gates ROHSTexas InstrumentsLogic Gates74LS74PC
DIP-140ns 0℃~+70℃ 1 2 20MHz 3.5pF 35ns@5V,50pF 4.5ns 4.75V~5.25V 400uA 74LS Series 8mA 8mA Asynchronous Complementary D-Type Rising Edge Set and Reset DIP-14 Flip FlopsTexas InstrumentsFlip Flops
IS61C5128AS-25QLI
SOP-32-11.3mm-40℃~+85℃ 15mA 25ns 4.5V~5.5V 4Mbit 900uA Auto power-down function Parallel Port (Parallel) SOP-32-11.3mm SRAM ROHSISSISRAM
MMBD1204
SOT-231 Pair Common Cathode 1.1V@300mA 100V 200mA 2A 50nA@50V SOT-23 Diodes - General Purpose ROHSonsemiDiodes - General Purpose
README
README.mdSegaCD_Ramcart
Sega Genesis/Megadrive CD Back-up RAM Cart
Design done in Kicad 5.1.10 with Digikey libraries. If you want to edit it, you'll need those libraries as well as these files.
Board tested working 9/3/21 after fixing A20/A22 accidental swap @ U4.
PCB revision 1.1 has this fixed. PCB revision 1.2 adds R2 to make sure the SRAM goes into sleep mode. The BOM has also changed.
RAM Cart tested 9/3 with Dark Wizard and does not have the save corruption issue that the Castlemania Ultra cart has.
CSV Format BOM & Gerbers added 10/30/21.
If you have an Etsy/eBay/Aliexpress/etc. cartridge and are experiencing low battery life, you'll need to swap parts at R1, D1, and U2 with the parts listed in the current BOM. You'll also need to add a 10k resistor from U2 Pin 22 to D1 Pin 3 (the single pin on top).
Parts
22| Qty | Value | Footprint | References |
|---|---|---|---|
| 7 | 0.1uF | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C1, C2, C3, C4, C5, C6, C7 |
| 2 | 74LS30 | digikey-footprints:SOIC-14_W3.9mm | U1, U3 |
| 2 | MountingHole | Sega CD RAM Cart:MountingHole_6.2mm | H1, H2 |
| 1 | 10k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R2 |
| 1 | 1K | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1 |
| 1 | 22uF 25v | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C8 |
| 1 | 74LS138 | digikey-footprints:SOIC-16_W3.90mm | U4 |
| 1 | 74LS245 | digikey-footprints:SSOP-20_W5.3mm | U7 |
| 1 | 74LS32 | digikey-footprints:SOIC-14_W3.9mm | U5 |
| 1 | 74LS74 | digikey-footprints:SOIC-14_W3.9mm | U6 |
| 1 | Battery_Cell | BU2450SM:BAT_BU2450SM-JJ-G | BT1 |
| 1 | Genesis_Edge_Connector | Sega CD RAM Cart:Genesis_Card_Edge | J1 |
| 1 | IS61C5128AS-25QLI | Package_SO:SSOP-32_11.305x20.495mm_P1.27mm | U2 |
| 1 | MMBD1204 | digikey-footprints:SOT-23-3 | D1 |
Similar boards
- 2 layers99.7 × 149.9 mm
- 4 layers304.8 × 215.9 mm
64 256KB SYSTEM BOARD
kev-ju/PC-Retro-MTM
Modern KiCad version of the IBM 5150 system board originally created by MTM Scientific, Inc.
197 parts4 - 6 layers244 × 244 mm
Retroslop
CPTforever/8088-MicroATX-Computer
A 8088 based, IBM 5150 like computer compatible with the MicroATX motherboard form factor.
193 parts - 4 layers129.5 × 106.7 mm
- 4 layers129.5 × 55 mm
Amiga500 Actionreplay 5
Gnome78/MKV_4_DENISE_ITX
Action Replay MK3 For DeniseITX (Based Of Demon Card Project for Amiga)
47 parts1 - 2 layers203.4 × 139.1 mm
Tandy Color Computer Multi Pak
djtersteegc/Tandy-Color-Computer-Multi-Pak
Respin of the Tandy 26-3024 Multi-Pak (MPI) for the DIY builder.
70 parts16MIT - 2 layers98.3 × 107.1 mm
Coco9511pak
barberd/coco9511pak
This board is a cartridge for the Tandy Radio Shack TRS-80 Color Computer (CoCo), an 8 bit computer produced between 1980 and 1991. It provides an Arithmetic Processor Unit (APU), the AMD 9511, to the CoCo.
44 parts13GPL-3.0
Questions
How big is the SegaCD Ramcart PCB?
It measures 83.8 × 61.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the SegaCD Ramcart use?
22 parts, built around the 74LS245SC, 74LS30PC, 74LS32SC and 74LS74PC. 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 SegaCD Ramcart KiCad files?
From the WindDrake/SegaCD_Ramcart repository on GitHub, at the commit this page was made from: the board is Sega CD RAM Cart.kicad_pcb and its schematic Sega CD RAM Cart.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the SegaCD Ramcart design in my own project?
Its repository states no licence, so its author keeps all rights: ask WindDrake before reusing the design.