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PCA9306 Level Shifter Molecule

Public Made by Adom

by adom

Bidirectional 2-channel I2C/SMBus voltage-level translator molecule (TI PCA9306DCUR) — 1.8 V <-> 3.3 V, no one-shot ACK contention, 24x16 mm 4-pin Adom workcell molecule with 8 medium machine contacts

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PCA9306 Level Shifter Molecule — Plan

Brief

Drop-in I²C / SMBus voltage-level translator molecule for Adom workcells. Bridges a 1.8 V bus to a 3.3 V (or up to 5 V) bus with no direction pin and no one-shot accelerator contention — the canonical replacement for the TXS0108E on the Bosch sensortec arm board, where the TXS family's one-shot rising-edge accelerator fights I²C slave open-drain ACK pull-down and produces address-NACK at probe time.

Decisions

  • Tool: adom-tsci / tscircuit (canonical Adom path).
  • Size: 24x16 — 4-pin molecule. Wider than tall so 4 + 4 perimeter contacts fit comfortably.
  • Pin grid: medium machine pins (4 corner pins + 4 edge contacts per long side).
  • IC: TI PCA9306DCUR in VSSOP-8 (DCU package). LCSC C58662 (JLC extended).
  • EN handling: internally tied to VREF2 via a 10 kΩ pull-up (always-enabled by default). Cut the R5 trace if external EN control is needed later.
  • Pull-ups: 4.7 kΩ on SDA1, SCL1 → VREF1; 4.7 kΩ on SDA2, SCL2 → VREF2. UNI-ROYAL 0402 (LCSC C25900 — JLC basic).
  • Decoupling: one 100 nF 0402 X7R on each VREF rail, placed within 1 mm of the IC pin. Samsung CL05B104KO5NNNC (LCSC C1525 — JLC basic).
  • Top silkscreen: "PCA9306", function tag, pin labels on every contact.
  • Bottom silkscreen: part name, "1.8V <-> 3.3V I2C", version + author + date.

Components

Ref Value Package MPN LCSC
U1 PCA9306DCUR VSSOP-8 PCA9306DCUR C58662
C1, C2 100 nF 25 V X7R 0402 CL05B104KO5NNNC C1525
R1..R4 4.7 kΩ 1 % 0402 0402WGF4701TCE C25900
R5 10 kΩ 1 % 0402 0402WGF1002TCE C25744

Workcell interface (8 medium machine contacts)

Pin Net Side Notes
MC_VREF1 VREF1 left (LV) 1.71–1.89 V supply
MC_SDA1 SDA1 left 1.8 V SDA, 4.7 kΩ to VREF1
MC_SCL1 SCL1 left 1.8 V SCL, 4.7 kΩ to VREF1
MC_GND1 GND left shared ground
MC_VREF2 VREF2 right (HV) 3.3 V supply
MC_SDA2 SDA2 right 3.3 V SDA, 4.7 kΩ to VREF2
MC_SCL2 SCL2 right 3.3 V SCL, 4.7 kΩ to VREF2
MC_GND2 GND right shared ground

Don'ts

  • No BGA / 0201.
  • No external EN pin.
  • Only one JLC extended part (U1 itself); everything else basic-tier.

Publish

cd ~/project/adom-tsci-projects/pca9306-level-shifter
bun install
bunx tsci build lib/index.tsx --glbs --svgs --3d-png --pcb-png
adom-tsci start .
adom-tsci export-wiki --slug pca9306-level-shifter --page-type molecules