Power Entry Stage Design
Started implementing a plan
#Goal
- Refine the PCB component placement for the SAR receiver board using the SAR PCB constraints markdown file as the primary engineering reference. The updated placement should optimize for the dedicated RF chain (left, with linear ordering from J3 to C19 to U7 to U8 to U6), proper PLL filter placement (immediately beside U9, which should be near U8), signal integrity for the ADC bus (ADC placed center-left with a straight path toward the FPGA), correct FPGA orientation (centered with ADC-facing pins on the left and FIFO/USB-facing pins on the right), and secure placement of FT2232H near the USB connector on the right. Additionally, assign power devices along the top edge and arrange debug/test/reset/LEDs along the bottom edge, all while preserving RF isolation, routing corridors, bus ordering, and connectivity from the schematic.
#Implementation plan
1. **Review Constraints and Layout Floorplan**
1. Read and verify the SAR PCB constraints markdown file to extract specific placement coordinates, keepout zones, and orientation requirements.
2. Reference the existing project context (80x50 mm 4-layer board) and the schematic connectivity.
2. **Zone and Group Refinement**
1. Define functional placement zones:
1. RF chain zone on left (RF components: J3, C19, U7, U8, U6).
2. PLL zone with U9 positioned near U8 and the PLL filter placed directly beside U9.
3. ADC zone on center-left with ADC bus aligned toward FPGA input pins.
4. FPGA zone centered with its ADC-facing pins on the left and FIFO/USB-facing pins toward the right.
5. USB/FT2232H zone on right, with FT2232H placed near the USB connector.
6. Power components along the top edge.
7. Debug/test/reset/LED components along the bottom edge.
3. **Placement-Only Optimization**
1. Place and refine component positions to facilitate continuous routing corridors and minimal airwires while ensuring component separation, specifically enforcing RF isolation.
2. Ensure that bus signals (ADC and FIFO) are routed in a straight, consistent pattern according to the provided direction instructions.
4. **Validation and Readiness Check**
1. Validate placement for any overlaps, violations of keepout zones, or misalignments against the markdown constraints.
2. Confirm that all functional zones preserve their unique isolation and routing channels.
3. Finalize layout freeze candidate that is ready for staged routing.
#Success criteria
- RF chain components are positioned from left to right in the order J3 → C19 → U7 → U8 → U6, with the PLL (U9) next to its filter.
- ADC is placed center-left with its bus straight toward FPGA, and the FPGA is centered as specified.
- USB/FT2232H area correctly placed near the USB connector on the right; power components along the top, and debug/test/reset/LEDs along the bottom.
- Routing corridors, RF isolation, and required bus order are fully preserved.
- The placement adheres strictly to the SAR PCB constraints markdown file with no schematic connectivity violations.
Read constraints and current placement
1:06
Applied initial floorplan refinement
18:42
flux
Task completed.
11:49
flux
flux
- Refined PCB component placement only; no routing was performed.
- Floorplanned the SAR board per the constraints file: RF chain left in order
J3 → C19 → U7 → U8 → U6,U9nearU8, PLL filter parts besideU9, ADC center-left, FPGA centered, FT2232H/USB on the right, power along the top, and debug/test/LED/reset along the bottom. - Ran a focused cleanup pass to keep the crystal loop and power-entry/debug access from crowding while preserving the routing corridors.
- ✅ RF chain ordering and left-side RF isolation corridor are preserved.
- ✅ PLL filter remains immediately beside
U9, withU9close toU8for a short LO path. - ✅
U6is center-left and ADC bus series parts are betweenU6andU3for a straight bus channel. - ✅
U3remains centered with bus corridors preserved toward ADC on the left and FIFO/USB on the right. - ✅
U5andJ2are grouped on the right with USB support/ESD nearby. - ✅ Power and debug sections are assigned to the top and bottom edges respectively.
- ✅ Schematic connectivity was not changed and no PCB routing was created.
- Proceed with staged routing: RF first, then PLL/ADC clock, ADC bus, USB pair, FIFO bus, power, and finally debug/GPIO.
