SRAM Board 2MB
About the SRAM Board 2MB
SRAM Board 2MB is an open source PCB design by kr239, published on GitHub under the GPL-2.0 license. It is a 2-layer board measuring 125.7 × 33 mm, with 48 components from 9 distinct parts.
Other key parts include the 74ABT00, 74ABT821ADW, 74ABT32, CY62157ESL-45ZSXI and 74ABT373. By type, the board carries 32 connectors, 8 ICs and 8 capacitors.
It belongs with the retro computing designs in this gallery.
From the project
Replace the old 44256 DRAM chips on your A500 with newer SRAM memory
This is a significantly revised design based around two SRAM chips, using the buffered A9 input from U34 to provide sufficient address lines. This board will give 2MB CHIP RAM in an A500+ & the trapdoor expansion will be rendered useless for any memory expansions.
This board also has seen the design optimized significantly for low z-height, meaning it shouldn't foul the keyboard in a stock A500+ case.
Main components on the SRAM Board 2MB
SRAM Board 2MB bill of materials (BOM)
48 components, 9 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 74ABT00 | SOIC-14_3.9x8.7mm_P1.27mm | U1 |
| 1 | 74ABT821ADW | SOIC-24W_7.5x15.4mm_P1.27mm | U2 |
| 1 | 74ABT32 | SOIC-14_3.9x8.7mm_P1.27mm | U3 |
| 2 | CY62157ESL-45ZSXI | TSOP-II-44_10.16x18.41mm_P0.8mm_copy | U4, U5 |
| 1 | 74ABT373 | SOIC-20W_7.5x12.8mm_P1.27mm | U6 |
| 1 | 74AHCT1G79 | SOT-353_SC-70-5_Handsoldering | U7 |
| 1 | 74LS373 | DIP-20_W7.62mm_Socket_LongPads | U34 |
| 32 | Conn_01x01 | PinHeader_1x01_P2.54mm_Vertical | J1, J2, J3, J4, J5, J6, J7, J8 +24 |
| 8 | 0.1uF | C_1206_3216Metric_Pad1.42x1.75mm_HandSolder | C1, C2, C3, C4, C5, C6, C7, C8 |
SRAM Board 2MB design files
The KiCad project lives in the kr239/A500-SRAM-Board repository on GitHub; these links point at the commit this page was built from.
SRAM Board 2MB: common questions
How big is the SRAM Board 2MB?
The SRAM Board 2MB measures 125.7 × 33 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the SRAM Board 2MB?
48 components, from 9 distinct parts. The full bill of materials is listed on this page.
Where can I download the SRAM Board 2MB design files?
From the kr239/A500-SRAM-Board repository on GitHub, which has the KiCad layout; the links under Design files point to each one.
Can I use the SRAM Board 2MB design in my own project?
Yes, under the terms of its GPL-2.0 license, which kr239 chose for the repository.
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