74Logic SA ADC
About the 74Logic SA ADC PCB
74Logic SA ADC is an open source PCB design by schilkp, published on GitHub under the MIT license. It is a 2-layer board measuring 95.9 × 69.2 mm, with 189 components from 39 distinct parts.
Other key parts include the SN74LVC1G04DCK, SN74LVC1G08DCK, SN74LVC1G32DCK, SN74HC245DBR and 74LVC1G157GW. By type, the board carries 58 resistors, 46 capacitors, 39 ICs, 34 diodes, 4 test points and 3 connectors.
From the project
A discrete Successive Approximation ADC built from individual logic gates.
Built to understand SA-ADCs, and serve as a demonstration unit.
As this is a demonstration unit only really meant for DC inputs, no Sample-&-Hold stage is included.
This Project uses the classic DAC-based Successive Approximation Architecture Wikipedia.
It is essentially an analog implementation of a binary-search algorithm. The ADC first sets it's DAC to 2.5V (Vref/2), and uses an analog comparator to determine if the applied input voltage is higher or lower than the generated voltage. Depending on the comparator's output the DAC voltage is then repeatedly refined to determine each bit of…
Main components on the 74Logic SA ADC
74Logic SA ADC bill of materials (BOM)
189 components, 39 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 3 | SN74LVC1G04DCK | SOT-353_SC-70-5 | U1, U25, U27 |
| 1 | SN74LVC1G08DCK | SOT-353_SC-70-5 | U2 |
| 14 | SN74LVC1G32DCK | SOT-353_SC-70-5 | U3, U5, U6, U7, U8, U9, U10, U11 +6 |
| 1 | SN74HC245DBR | SSOP-20_5.3x7.2mm_P0.65mm | U4 |
| 7 | 74LVC1G157GW | SOT-363_SC-70-6 | U17, U18, U19, U20, U21, U22, U23 |
| 2 | SN74HC377DW | SOIC-20W_7.5x12.8mm_P1.27mm | U24, U26 |
| 1 | 74HC161D | SOIC-14_3.9x8.7mm_P1.27mm | U28 |
| 1 | SN74LVC1G175DCK | SOT-363_SC-70-6 | U29 |
| 1 | SN74HC02D | SOIC-14_3.9x8.7mm_P1.27mm | U30 |
| 1 | SN74HC08D | SOIC-14_3.9x8.7mm_P1.27mm | U31 |
| 1 | LM358ST | MSOP-8_3x3mm_P0.65mm | U34 |
| 3 | 74LVC1G17DCK | SOT-353_SC-70-5 | U35, U45, U48 |
| 1 | LM317 | TO-252-2 | U37 |
| 1 | L7805CDT | TO-252-2 | U38 |
| 1 | NE555DR | SOP-8_3.9x4.9mm_P1.27mm | U44 |
| 1 | Vin | PinHeader_1x03_P2.54mm_Vertical | J1 |
| 1 | Power | PinHeader_1x02_P2.54mm_Horizontal | J2 |
| 1 | Out | PinHeader_1x08_P2.54mm_Vertical | J3 |
| 1 | 10K | Potentiometer_Alps_RK09K_Single_Vertical | RV1 |
| 1 | 1Meg | Potentiometer_Bourns_3386P_Vertical | RV2 |
Show 19 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 2 | SW_Push_SPDT | PinHeader_1x03_P2.54mm_Vertical | SW1, SW3 |
| 1 | SW_Push | SW_PUSH_6mm | SW2 |
| 1 | Vin | TestPoint_Keystone_5019_Minature | TP1 |
| 1 | Vdac | TestPoint_Keystone_5019_Minature | TP2 |
| 1 | CompOut | TestPoint_Keystone_5019_Minature | TP3 |
| 1 | GND | TestPoint_Keystone_5019_Minature | TP4 |
| 34 | LED | LED_0603_1608Metric | D1, D2, D3, D4, D5, D6, D7, D8 +26 |
| 40 | 0u1 | C_0603_1608Metric | C1, C2, C3, C4, C5, C6, C7, C8 +32 |
| 4 | DNS | C_0603_1608Metric | C35, C38, C39, C49 |
| 2 | 100u | CP_Elec_8x6.5 | C40, C41 |
| 34 | 39K | R_0603_1608Metric | R1, R2, R3, R4, R5, R6, R7, R8 +26 |
| 3 | 10K | R_0603_1608Metric | R10, R59, R60 |
| 1 | 270R | R_0603_1608Metric | R36 |
| 1 | 1K | R_0603_1608Metric | R37 |
| 1 | 100R | R_0603_1608Metric | R38 |
| 1 | DNS | R_0603_1608Metric | R39 |
| 9 | 20K 0.1% | R_0603_1608Metric | R41, R42, R43, R44, R45, R46, R47, R48 +1 |
| 7 | 10K 0.1% | R_0603_1608Metric | R50, R51, R52, R53, R54, R55, R56 |
| 1 | 5K6 | R_0603_1608Metric | R57 |
74Logic SA ADC design files
The KiCad project lives in the schilkp/74Logic_SA_ADC repository on GitHub; these links point at the commit this page was built from.
- LayoutKiCad/SA-ADC.kicad_pcb
74Logic SA ADC: common questions
How big is the 74Logic SA ADC PCB?
The 74Logic SA ADC measures 95.9 × 69.2 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the 74Logic SA ADC?
189 components, from 39 distinct parts. The full bill of materials is listed on this page.
Where can I download the 74Logic SA ADC design files?
From the schilkp/74Logic_SA_ADC repository on GitHub, which has the KiCad layout; the links under Design files point to each one.
Can I use the 74Logic SA ADC design in my own project?
Yes, under the terms of its MIT license, which schilkp chose for the repository.