Document Review and Assistance


Route the board now using low-noise analog layout practices.
I’ll route the PCB with priority on low-noise analog paths: short sensor-to-AFE/ADC connections, clean reference/power distribution, and separated digital control routing, then run airwire/DRC checks.
I’m blocked now because the account has no available ACUs, so I can’t run the final post-route DRC/airwire verification.
Accomplished this session:
  • Ran pre-route validation: board was routable with 51 PCB components / 47 nets.
  • Auto-routed the board, adding 880 routing nodes.
  • Found post-route issues: 2 airwires and 4 overlapping-copper errors, localized mainly around C15 GND plus GND connectivity near U9/U5.
  • Removed two conflicting trace segments and ran one cleanup auto-route pass, adding 9 routing nodes.
Open items:
  • Final DRC/airwire check still needs to be run once ACUs are available.
  • If errors remain, inspect C15 GND pad / bulk capacitor footprint area first.
  • Low-noise analog routing should be visually reviewed before fabrication, especially sensor → LMP91000 → ADC paths and the 2.5 V reference routing.
Suggested next steps:
  1. Re-run full post-route DRC and airwire checks.
  2. Fix any remaining localized C15/GND overlap issues.
  3. Review analog/reference routing quality manually before generating manufacturing files.
Run final checks
Fix C15 GND
Review analog routing
Check ground returns
Checks and cleanup

J1
U1
U4
U2
U3
R4
Resistance
1kΩ
R3
Resistance
1kΩ
R8
Resistance
20Ω
R5
Resistance
1kΩ
R9
Resistance
20Ω
R14
Resistance
DNP Ω
R2
Resistance
10kΩ
R6
Resistance
1kΩ
R13
Resistance
DNP Ω
R11
Resistance
DNP Ω
R7
Resistance
20Ω
R1
Resistance
10kΩ
R10
Resistance
20Ω
R12
Resistance
DNP Ω
C14
Capacitance
DNP F
C17
Capacitance
0.1uF
C3
Capacitance
0.1uF
J4
J3
J8
C10
Capacitance
0.1uF
J2
C8
Capacitance
0.1uF
J5
C6
Capacitance
0.1uF
J6
C5
Capacitance
0.1uF
C11
Capacitance
DNP F
J7
C15
Capacitance
100uF
C4
Capacitance
0.1uF
C16
Capacitance
0.1uF
C7
Capacitance
0.1uF
C13
Capacitance
DNP F
C9
Capacitance
0.1uF
C12
Capacitance
DNP F
JP1
TP9
Q3
TP5
U9
TP6
U5
TP7
TP1
TP13
TP14
U8
U6
TP2
TP4
Q1
Q4
TP3
U7
TP8
TP11
Q2
TP10
TP12

4-Channel Gas Sensor AFE

4-Channel Gas Sensor AFE thumbnail