Below is a schematic update suggestion that adds all the specified parts with their size‐optimized footprints for the compact 30×20 mm board:
Schematic Update Suggestions:
Battery Subsystem:
Add an SMD coin cell holder for the CR1220 with a footprint near 10 mm × 2.5 mm and height ~2.5 mm.
This holder will be used to mount the CR1220 (3V, 35 mAh).
Microcontroller:
Place the ATtiny20 QFN-20 with its compact 3×3 mm footprint and 0.8 mm thickness.
Include a 0.1µF (0603) decoupling capacitor (e.g., 0.1µF Capacitor) close to its power pins.
LED Subsystem:
Add an ultra-compact 0603 SMD LED (1.6 mm × 0.8 mm × 0.6 mm).
Connect a 220Ω (0603) current-limiting resistor (e.g., 220Ω Resistor) in series with the LED.
Push Button Subsystem:
Place an SMD tactile push button sized about 3 mm × 3 mm × 1.5 mm.
Include a 10kΩ (0603) resistor (e.g., 10kΩ Resistor) as a pull-up resistor for the push button signal.
DIP Switch Subsystem:
Add a DIP switch; you can choose either a 6-bit unit (e.g., 6-bit SMD DIP switch) or a 7-bit version if you require a range up to 99.
For each switch contact, include an individual 10kΩ (0603) pull-up resistor (10kΩ Resistor).
Layout Constraints:
Ensure that each component footprint is chosen or scaled to meet the board’s overall dimensions (~30×20 mm) while keeping the total device height ≤6 mm.
Use SMD components on both sides if needed and consider a custom double-sided FR4 PCB (0.8 mm thick) to optimize space.
You can use the "Apply changes" button to update your schematic with these component additions and ensure that each part's footprint meets the specified compact design requirements. Let me know if you need wiring recommendations or further modifications!
Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portal
General Purpose Thick Film Standard Power
and High-Power Chip Resistor
47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film
Features:
- RMCF – standard power ratings
- RMCP – high power ratings
- Nickel barrier terminations standard
- Power derating from 100% at 70ºC to zero at +155ºC
- RoHS compliant, REACH compliant, and halogen free
- AEC-Q200 compliant