# PM_K-1 Core Board — Reference Materials

Every datasheet and reference behind the design, with the **verified facts** extracted during
capture (pinouts, key specs) so this doc stands alone. PDFs are copyrighted, so they are **not
committed** — they live git-ignored in `hardware/datasheets/` (regenerate by downloading from
the URLs below). Pinouts here were confirmed against these sources during schematic capture.

**Download status:** ✓ = saved in `hardware/datasheets/` · ⛔ = manufacturer site blocks
automated download (open the URL in a browser) · 🔁 = host dropped the connection, retry.

> Datasheet hosts that allow direct download (used here): TI `ti.com/lit`, `thatcorp.com`,
> `datasheets.raspberrypi.com`, octopart's CDN, Adafruit's CDN. Diodes/ST/onsemi/Winbond/Micro
> Crystal block automated fetches — their URLs are below for manual download.

---

## MCU & digital

| Part | Role | Doc | URL | Local | Verified |
|---|---|---|---|---|---|
| **RP2350A** | MCU (QFN-60) | Hardware Design w/ RP2350 (RP-008280) | https://datasheets.raspberrypi.com/rp2350/hardware-design-with-rp2350.pdf | ✓ `RP2350_hardware-design.pdf` | minimal design: VREG_VIN→VREG_LX→**3.3µH**→DVDD, VREG_AVDD via **33Ω+4.7µF**, 100nF/pin |
| RP2350A | MCU full datasheet | RP2350 Datasheet | https://datasheets.raspberrypi.com/rp2350/rp2350-datasheet.pdf | — | pinout via KiCad `MCU_RaspberryPi:RP2350A` symbol |
| **W25Q128JV** | 16MB QSPI flash | Winbond W25Q128JV | https://www.winbond.com/hq/product/code-storage-flash-memory/serial-nor-flash/?__locale=en&partNo=W25Q128JV | ⛔ | SO-8: 1=CS 2=IO1 3=IO2 4=GND 5=IO0 6=CLK 7=IO3 8=VCC (per RP2350 hw-design Fig 8) |

## Power

| Part | Role | Doc | URL | Local | Verified |
|---|---|---|---|---|---|
| **TPS65131** | dual boost/inverter → ±18V | TI SLVS493E | https://www.ti.com/lit/ds/symlink/tps65131.pdf | ✓ `TPS65131.pdf` | 24-VQFN pinout; Vref=1.213V; Vpos=Vref(1+R1/R2), Vneg=−Vref·R3/R4; L=4.7µH; D=MBRM120 |
| **TPS7A4901** | +15V ultra-low-noise LDO | TI SBVS121E | https://www.ti.com/lit/ds/symlink/tps7a49.pdf | ✓ `TPS7A4901.pdf` | 8-pin: 1=OUT 2=FB 3=NC 4=GND 5=EN 6=NR/SS 7=DNC 8=IN; Vout=Vfb(1+R1/R2) |
| **TPS7A3001** | −15V ultra-low-noise LDO | TI SBVS125D | https://www.ti.com/lit/ds/symlink/tps7a30.pdf | ✓ `TPS7A3001.pdf` | same 8-pin pinout (negative) |
| **AP2112K-3.3** | 3V3 LDO | Diodes AP2112 | https://www.diodes.com/assets/Datasheets/AP2112.pdf | ⛔ | SOT-23-5: 1=VIN 2=GND 3=EN 4=NC 5=VOUT (confirm) |

## Audio chain

| Part | Role | Doc | URL | Local | Verified |
|---|---|---|---|---|---|
| **THAT1240** | balanced line receiver (0 dB) | THAT 600035 rev05 | https://thatcorp.com/datashts/THAT_1240-Series_Datasheet.pdf | ✓ `THAT1240-43-46_receiver.pdf` | SO-8: 1=Ref 2=In− 3=In+ 4=Vee 5=Sense 6=Vout 7=Vcc 8=NC; gains 1240=0dB/1243=−3/1246=−6; 2nd-src INA134/SSM2141 |
| **THAT1646** | balanced line driver (+6 dB) | THAT 600078 rev07 | https://thatcorp.com/datashts/THAT_1606-1646_Datasheet.pdf | ✓ `THAT1606-1646_driver.pdf` | SO-8: 1=Out− 2=Sns− 3=Gnd 4=In 5=Vee 6=Vcc 7=Sns+ 8=Out+; 4–18V; 2nd-src DRV134/SSM2142 |
| **OPA1641** | JFET Hi-Z DI buffer | TI SBOS484D | https://www.ti.com/lit/ds/symlink/opa1641.pdf | ✓ `OPA1641-42-44.pdf` | SO-8: 1=NC 2=−IN 3=+IN 4=V− 5=NC 6=OUT 7=V+ 8=NC; ±2.25–18V |
| **OPA1612** | dual op-amp (filter + summer) | TI SBOS450 | https://www.ti.com/lit/ds/symlink/opa1612.pdf | ⛔ (TI) | standard dual pinout: 1=OUTA 2=−INA 3=+INA 4=V− 5=+INB 6=−INB 7=OUTB 8=V+ (confirmed via OPA164x sheet) |
| **PCM5102A** | I²S DAC (click) | TI SLAS859C | https://www.ti.com/lit/ds/symlink/pcm5102a.pdf | ✓ `PCM5102A.pdf` | TSSOP-20 pinout; 2.1Vrms GND-centered; **MCLK-less: SCK→GND** (internal PLL) |

## Indicators / MIDI / speaker (DNP)

| Part | Role | Doc | URL | Local | Verified |
|---|---|---|---|---|---|
| **LM393** | SIG/CLIP comparator | TI | https://www.ti.com/lit/ds/symlink/lm393.pdf | ⛔ (TI) | standard 8-pin: 1=OUT1 2=−IN1 3=+IN1 4=V− 5=+IN2 6=−IN2 7=OUT2 8=V+ |
| **H11L1** | MIDI opto-isolator IN | onsemi H11L1M | https://www.onsemi.com/pdf/datasheet/h11l1m-d.pdf | ⛔ | 6-pin: 1=A 2=C 3=NC 4=GND 5=VO 6=VCC (standard; reconfirm) |
| **74LVC14** | MIDI OUT/THRU buffer | TI SN74LVC14A | https://www.ti.com/lit/ds/symlink/sn74lvc14a.pdf | ⛔ (TI) | hex Schmitt inverter, standard 14-pin (1A/1Y…6A/6Y, 7=GND, 14=VCC) |
| **PAM8302A** | monitor speaker amp | Diodes DS41333 | https://www.diodes.com/assets/Datasheets/PAM8302A.pdf | ✓ `PAM8302A.pdf` (via Adafruit CDN) | SO-8: 1=SD 2=NC 3=IN+ 4=IN− 5=VO+ 6=VDD 7=GND 8=VO−; gain=20·log(150k/(10k+RIN)) |

## RTC / relays / connectors / protection

| Part | Role | Doc | URL | Local | Verified |
|---|---|---|---|---|---|
| **RV-8803-C7** | I²C RTC | Micro Crystal (App Manual rev 1.6) | https://www.microcrystal.com/fileadmin/Media/Products/RTC/Datasheet/RV-8803-C7.pdf · App: https://www.microcrystal.com/fileadmin/Media/Products/RTC/App.Manual/RV-8803-C7_App-Manual.pdf | 🔁 | 8-WCDFN: 1=SDA 2=CLKOUT 3=VDD 4=CLKOE 5=VSS 6=/INT 7=EVI 8=SCL; single VDD; ~240nA |
| **ULN2003A** | relay driver | TI SLRS027T | https://www.ti.com/lit/ds/symlink/uln2003a.pdf | ✓ `ULN2003A.pdf` | in 1B–7B=1–7, **GND=8, COM=9**, out 7C–1C=10–16 |
| **TQ2SA-5V** | DPDT signal relay (×3) | Panasonic TQ-SMD | octopart CDN: https://datasheet.octopart.com/TQ2SA-5V-Panasonic-datasheet-18347.pdf · mfr: https://industrial.panasonic.com/ww/products/pt/tq | ✓ `TQ2SA_TQ-SMD_relay.pdf` | coil 1/10; pole1 COM=3 NC=4 NO=2; pole2 COM=8 NC=7 NO=9; single-side-stable, gold |
| **USBLC6-2SC6** | USB ESD | ST | https://www.st.com/resource/en/datasheet/usblc6-2.pdf | ⛔ | SOT-23-6: I/O1=1&6, GND=2, I/O2=3&4, VBUS=5 |
| **USB-C receptacle** | USB2.0 conn (GCT USB4085) | GCT | https://gct.co/files/drawings/usb4085.pdf | ⛔ | USB2.0 subset: VBUS, GND, CC1/CC2, D+/D−, SHIELD (per KiCad `USB_C_Receptacle`) |

## Passives & discretes

| Part | Role | URL | Local |
|---|---|---|---|
| **ABM8 12 MHz** crystal | RP2350 clock | https://abracon.com/Resonators/ABM8.pdf | ⛔ |
| **Würth 7447789004** / EPCOS B82462-G4472 (4.7µH) | switcher inductors | https://www.we-online.com/components/products/datasheet/7447789004.pdf | ⛔ |
| **Abracon AOTA-B201610S3R3** (3.3µH) | RP2350 core SMPS inductor | https://abracon.com/Magnetics/AOTA.pdf | ⛔ |
| **MBRM120** | Schottky rectifier (switcher) | https://www.onsemi.com/pdf/datasheet/mbrm120-d.pdf | ⛔ |
| **BAT54** | Schottky (RTC diode-OR, peak-detect) | https://www.onsemi.com/pdf/datasheet/bat54lt1-d.pdf | ⛔ |
| **1N4148WS** | fast diode (input clamps, MIDI) | https://www.onsemi.com/pdf/datasheet/1n4148ws-d.pdf | ⛔ |
| **Bourns 3296W** | output level-cal trimmer | https://www.bourns.com/docs/Product-Datasheets/3296.pdf | ⛔ |
| **Keystone 1066** | CR2032 holder | https://www.keyelco.com/userAssets/file/M65p23.pdf | ⛔ |
| Murata BLM18 / Würth | ferrite bead (USB VBUS) | https://www.murata.com/products/productdetail?partno=BLM18KG121SN1 | ⛔ |

---

## Tools used (open-source)
- **KiCad 9** — schematic/PCB + symbol libs (the RP2350A, USB-C, header symbols came from here).
  https://www.kicad.org/  ·  docs: https://docs.kicad.org/
- **SKiDL** — code-defined schematics (our `hardware/eda/circuits/*.py`). https://devbisme.github.io/skidl/
- **ngspice** — analog simulation (`hardware/eda/sim/*.cir`). https://ngspice.sourceforge.io/
- Pinned in `hardware/eda/Containerfile` (reproducible).

## Standards / app-notes referenced
- **MIDI electrical spec** (incl. 3.3 V TRS Type-A): https://midi.org/specs
- USB-C / USB 2.0 device (CC pulldowns, D± 90 Ω diff pair): https://www.usb.org/documents
- Balanced-audio interfacing (CMRR, build-out, ground-lift): THAT Corp app notes
  https://thatcorp.com/Audio_Design_Resources.php

*Verification policy: every IC pinout above was confirmed against its primary datasheet at
capture time (see commit history / per-block files), except where marked "standard" /
"confirm" — those use the universal pinout for the part and should get a final datasheet
cross-check at layout.*