Aurora Hearing Device Design
Worked for 29 sec
Blocked: your account is currently out of ACUs, so I can’t mutate the board/layout further in this run.
Accomplished this session:
- Started the 12 mm product-like redesign workflow.
- Loaded the required layout/component procedures for the crescent board, compact part replacement, and placement constraints.
- Confirmed the next execution plan: 12 mm max-width smooth crescent, 4-layer stackup, compact USB-C replacement, high-SPL mic replacement, removal/shrinking of bulky hook-side parts, and dense two-sided placement.
Remaining:
- Apply the new 12 mm crescent board outline and 4-layer stackup.
- Replace/flag oversized parts: current USB-C, ICS-40730 mics, large flash, tactile switch, and bulky connectors.
- Re-place the hook PCB components into the slim crescent form factor.
- Run layout fit/congestion checks and update the project documentation.
Estimate the ACUs needed to finish the 12 mm redesign.
Thought for 5 sec
Estimate: ~25–45 ACUs to finish a credible 12 mm hook redesign pass.
Breakdown:
- Apply 12 mm crescent outline + 4-layer stackup: 2–5 ACUs
- Research/replace compact USB-C + high-SPL mics + smaller flash/switch/connectors: 6–12 ACUs
- Re-place dense two-sided hook layout: 8–15 ACUs
- Fit/congestion/layout verification: 4–8 ACUs
- Update project docs and next-step notes: 2–5 ACUs
If we also route the board afterward, budget another 40–90 ACUs, because fine-pitch nRF5340/CS47L63, RF, USB, and dense wearable placement will likely need multiple iterations.
Proceed after ACUs
Prioritize fit check
Research compact parts
Update migration plan
Review power impact
Refine this doc
Ask about this doc
Schematic Wiring Status — Project Aura
Status
Core schematic wiring and the main support-passive pass are complete. A focused electrical/passive review now reports no open warnings for floating pins, no-connects, power pins, single-pin nets, shorted components, undriven nets, decoupling caps, capacitor voltage rating, or pull-up/pull-down checks.
Remaining work is now primarily schematic readability cleanup and PCB/layout-stage validation: RF physical placement/keepout, controlled-impedance routing, VNA antenna tuning, and final audio/power validation before manufacturing.
Major Correction Made During Wiring
The 7-conductor flex interpretation was revised after the analog ICS-40730 hook microphones were added.
Corrected placement assumption:
- Hook side: nRF5340, nPM1100, TLV62568 3V0 buck, flash, USB-C, battery connector, two ICS-40730 analog microphones, CS47L63, CS47 1V8/1V2 regulators.
- IEM side: three MAX98360A amplifiers and the three Knowles BA receivers.
Corrected 7-conductor flex signals:
- VSYS_AMP
- GND
- GND_SHIELD
- TDM_BCLK
- TDM_FSYNC
- TDM_DOUT
- AMP_EN
This preserves the 7-conductor constraint while avoiding the impossible case of sending two analog differential microphones across the same limited flex.
Wired Blocks
Power / Charging
- USB-C VBUS, CC1/CC2 sink pull-downs, USB D+/D− to nRF5340 and nPM1100 port-detect pins.
- JST-PH battery connector through BAT54 prototype Schottky protection to nPM1100 VBAT.
- nPM1100 VSYS to MAX98360A supply branch and TLV62568 VIN.
- nPM1100 charger configuration: 11 kΩ ICHG resistor for ~50 mA charge current, ISET low for USB detection/default 100 mA behavior, VTERMSET high for 4.2 V termination, MODE low, SHPHLD/SHPACT low, fixed 10 kΩ NTC resistor for prototype no-thermistor case, and DEC capacitor populated.
- nPM1100 VOUTB/SW are intentionally unused because the main 3V0 rail is provided by the external TLV62568 buck.
- TLV62568 3V0 buck: 2.2 uH inductor, 4.7 uF input cap, 10 uF output cap, 400k/100k feedback divider, 6.8 pF feed-forward cap.
- TPS79318 1V8_A rail for CS47L63 VDD_A.
- TLV70012 1V2_D rail for CS47L63 VDD_D.
Compute / Storage / USB
- nRF5340 VDD pins tied to 3V0; grounds tied to GND.
- nRF5340 Nordic reference DEC/DC-DC support added: DECR/DECRF, DECD, DECN, DECA, and DECUSB networks with reference values.
- SWDIO, SWDCLK, nRESET, GND, and 3V0 test pads added.
- W25Q01JV QSPI flash wired to nRF5340 P0.13–P0.18 QSPI pins.
- USB-C D+/D− wired to nRF5340 USB and nPM1100 USB detection.
- 32 MHz MP06003 crystal wired to nRF5340 XC1/XC2 with 12 pF load capacitors.
Audio / Control
- nRF5340 to CS47L63 control: I2C on P1.02/P1.03 with 4.7k pull-ups to 3V0.
- nRF5340 to CS47L63 stereo audio: I2S BCLK/FSYNC/DOUT to CS47L63 ASP2 input.
- CS47L63 VREF1_FILT and VREF2_FILT capacitors added per datasheet.
- CS47L63 VDD_LDO is intentionally unused because the external ICS-40730 MEMS microphones are powered from 3V0; per datasheet, VDD_LDO and LDO_FILT are tied to GND.
- CS47L63 to MAX98360A amps: ASP1 TDM BCLK/FSYNC/DOUT bus.
- MAX98360A TDM slot straps: U3 slot 0, U4 slot 1, U5 slot 2 by leaving U5 GAIN_SLOT open.
- AMP_EN from nRF5340 P0.25 to all MAX98360A EN pins and flex AMP_EN, with 100k pulldown default-off.
- MAX98360A outputs wired to WBFK, CI, and TWFK BA receiver terminals.
- ICS-40730 microphones now include local 0.1 uF VDD decoupling and 2.2 uF series DC-blocking capacitors on each differential output before the CS47L63 analog inputs.
RF
- Replaced the temporary direct nRF5340 ANT-to-antenna feed with a tunable RF matching footprint.
- Added L4 as the initial 1.5 nH series matching element based on Johanson 2450AT42E010B evaluation-board guidance.
- Added C30/C31 as optional DNP 0201 C0G/NP0 shunt tuning pads on the nRF side and antenna side of the series element.
- Marked RF_NRF_2G4 and RF_ANT_2G4 as 50 Ω controlled-impedance high-speed nets.
- Final component values still require final PCB geometry, antenna placement, and VNA tuning; Johanson notes that client PCB matching values will differ from evaluation-board values.
Latest Focused ERC Result
Focused review types checked:
- Floating pins
- No-connect issues
- Power pins
- Single-pin nets
- Pin-to-pin issues
- Shorted components
- Undriven nets
- Decoupling caps
- Pull-up / pull-down checks
- Capacitor voltage rating
Result: no open warnings or errors returned for those focused electrical/passive categories as of 2026-07-17.
Remaining Work Before Layout
- Clean up schematic readability: many auto-generated portals/wires are visually dense and can trigger schematic collision/readability warnings.
- During PCB setup, place the Johanson antenna and L4/C30/C31 matching network exactly per RF layout constraints, with short 50 Ω CPWG feed and appropriate ground/keepout behavior.
- VNA-tune the RF matching network on the final board; L4/C30/C31 values are starting/tuning placeholders, not production-final values.
- Verify MAX98360A logic thresholds with VSYS supply and 3V0 TDM input signals.
- Replace BAT54 Schottky with ideal-diode MOSFET protection if voltage drop/headroom is unacceptable.
- Add current-measurement jumpers or explicit test points for VSYS, 3V0, 1V8_A, 1V2_D, and amp supply if measurement priority is high.
- Confirm nRF5340 VDDH/DCCH regulator-mode choice against Nordic reference layout before final PCB layout.
Latest Change Note
2026-07-17: Added ICS-40730 microphone AC-coupling and local decoupling, tied unused CS47L63 LDO pins per datasheet, added the RF matching/tuning footprint, marked RF nets as 50 Ω, and re-ran focused electrical/passive ERC clean.
Status
Major Correction Made During Wiring
Wired Blocks
Power / Charging
Compute / Storage / USB
Audio / Control
RF
Latest Focused ERC Result
Remaining Work Before Layout
Latest Change Note
