4 layers74.2 × 42.7 mm
4 layers74.2 × 42.7 mm
128 kB Saturn 128k-compatible RAM expansion card for Apple II
- Size
- 74.2 × 42.7 mm
- Copper layers
- 4
- Thickness
- 1.61 mm
- Parts
- 57
- Nets
- 114
- Pads
- 328
- Tracks, vias
- 1,407, 408
- Pours
- 533
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 25 Jul 2020
- Updated
- 28 Apr 2025
Overview
RAM128 is an open-source printed circuit board by garrettsworkshop, from the garrettsworkshop/RAM128 repository on GitHub. It is a 4-layer board of 74.2 × 42.7 mm with 57 parts on 114 nets, routed with 1,407 tracks and 408 vias.
It is built around the 74AHCT1G126GW, 74HCT245PW and 74AHCT1G04GW, with the 74AHCT08PW, 74AHCT1G32GW and 74AHCT32PW among its other parts. Its parts include 20 ICs, 18 capacitors, 6 resistors, 1 connector and 1 switch.
Main components
7
74AHCT1G126GW
SOT-353-40℃~+125℃ 1 1 4.5V~5.5V 4.7ns@5V 40uA 74AHCT 8mA 8mA Output enable、Level shifting TTL compatible CMOS Tri-State Unidirectional SOT-353 Buffers, Drivers, Receivers, Transceivers ROHSMDDBuffers, Drivers, Receivers, Transceivers
74HCT245PW
TSSOP-20-40℃~+125℃ 1 12ns@4.5V,50pF 160uA 4.5V~5.5V 6mA 6mA 74HCT 8 Bidirectional Tri-State TSSOP-20 Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers74AHCT1G04GW
SOT-353-40℃~+125℃ 1 1 1uA 2V 3.7V 4.5V~5.5V 550mV 7.7ns@5V,50pF 74AHCT 800mV 8mA 8mA SOT-353 Inverters ROHSNexperiaInverters
74AHCT08PW
TSSOP-14-40℃~+125℃ 2V 2uA 4 4.5V~5.5V 7.9ns@5V,50pF 74AHCT Series 800mV 8mA 8mA AND Gate TSSOP-14 Logic Gates ROHSNexperiaGates
74AHCT1G32GW
TSSOP-5-40℃~+125℃ 1 2 2V 4.4V 4.5V~5.5V 40uA 550mV 7.9ns@5V,50pF 74AHCT 800mV OR Gate Overvoltage-tolerant input TSSOP-5 Logic Gates ROHSNexperiaGates74AHCT32PW
TSSOP-14-40℃~+125℃ 100mV、440mV 2 20uA 3.8V、4.4V 4 4.5V~5.5V 74AHCT Series 8mA 8mA OR Gate Overvoltage-tolerant input TTL compatible CMOS TSSOP-14 Logic Gates ROHSTexas InstrumentsLogic Gates74HCT273PW
TSSOP-20-40℃~+125℃ 1 12ns 3.5pF 30ns@4.5V,50pF 36MHz 3ns 4.5V~5.5V 4mA 5.2mA 74HCT Series 8 8uA Asynchronous D-Type Reset Rising Edge TSSOP-20 Flip Flops ROHSNexperiaFlip Flops
Parts
57| Qty | Value | Footprint | References |
|---|---|---|---|
| 16 | 2u2 | stdpads:C_0603 | C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C17, C18 |
| 8 | 74AHCT1G04GW | stdpads:SOT-353 | U12, U13, U14, U15, U16, U17, U19, U20 |
| 5 | stdpads:PasteHole_1.152mm_NPTH | H1, H2, H3, H4, H5 | |
| 4 | 22k | stdpads:R_0805 | R1, R2, R3, R4 |
| 4 | Fiducial | stdpads:Fiducial | FID1, FID2, FID3, FID4 |
| 3 | 74AHCT08PW | stdpads:TSSOP-14_4.4x5mm_P0.65mm | U6, U8, U9 |
| 2 | 10u | stdpads:C_0805 | C1, C16 |
| 2 | 74AHCT1G32GW | stdpads:SOT-353 | U5, U18 |
| 2 | 74AHCT32PW | stdpads:TSSOP-14_4.4x5mm_P0.65mm | U7, U10 |
| 2 | 74HCT273PW | stdpads:TSSOP-20_4.4x6.5mm_P0.65mm | U3, U4 |
| 2 | LOGO | LOGO | G***, G*** |
| 1 | 0 | stdpads:R_0805 | R5 |
| 1 | 621024 | stdpads:SOP-32_450mil | U1 |
| 1 | 74AHCT1G126GW | stdpads:SOT-353 | U11 |
| 1 | 74HCT245PW | stdpads:TSSOP-20_4.4x6.5mm_P0.65mm | U2 |
| 1 | AppleIIBus | stdpads:AppleIIBus_Edge | J1 |
| 1 | DMA/ROM | stdpads:SW_DIP_SPSTx02_Slide_DSHP02TS_P1.27mm | SW1 |
| 1 | DNP | stdpads:R_0805 | R6 |
Questions
How big is the RAM128 PCB?
It measures 74.2 × 42.7 mm and has 4 copper layers, 1.61 mm thick.
What parts does the RAM128 use?
57 parts, built around the 74AHCT1G126GW, 74HCT245PW, 74AHCT1G04GW and 74AHCT08PW. 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 RAM128 KiCad files?
From the garrettsworkshop/RAM128 repository on GitHub, at the commit this page was made from: the board is RAM128.kicad_pcb and its schematic RAM128.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the RAM128 design in my own project?
Its repository states no licence, so its author keeps all rights: ask garrettsworkshop before reusing the design.
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