Adafruit ISO1540 Bidirectional I2C Isolator
ISO1540-based galvanic isolation breakout for I2C buses, providing bidirectional SDA/SCL isolation between controller and device sides. Used to separate earth-grounded, high-voltage, or noisy power domains from a microcontroller I2C bus.
Pinout
- VCC
Power pin for each side of the isolator. Adafruit states each isolated side must be powered separately.
Type · PowerVoltage · 3 to 5 VDC on both isolated sides, source: Adafruit Learn pinouts - GND
Ground reference for each side of the isolator. Connect the reference ground on either side.
Type · Ground - SCL
I2C clock line on either isolated side. Adafruit notes a 10K pullup to that side's VCC.
Type · I2CVoltage · Pulled up to that side's VCC, source: Adafruit Learn pinouts - SDA
I2C data line on either isolated side. Adafruit notes a 10K pullup to that side's VCC.
Type · I2CVoltage · Pulled up to that side's VCC, source: Adafruit Learn pinouts - STEMMA QT
STEMMA QT / Qwiic connectors on either side for I2C dev boards and accessories.
Type · UnknownVoltage · Carries side-specific VCC/GND plus SDA/SCL; exact cable side follows board connector, source: Adafruit Learn pinouts
| Pin | Type | Function | Voltage |
|---|---|---|---|
| VCC | Power | Power pin for each side of the isolator. Adafruit states each isolated side must be powered separately. | 3 to 5 VDC on both isolated sides, source: Adafruit Learn pinouts |
| GND | Ground | Ground reference for each side of the isolator. Connect the reference ground on either side. | |
| SCL | I2C | I2C clock line on either isolated side. Adafruit notes a 10K pullup to that side's VCC. | Pulled up to that side's VCC, source: Adafruit Learn pinouts |
| SDA | I2C | I2C data line on either isolated side. Adafruit notes a 10K pullup to that side's VCC. | Pulled up to that side's VCC, source: Adafruit Learn pinouts |
| STEMMA QT | Unknown | STEMMA QT / Qwiic connectors on either side for I2C dev boards and accessories. | Carries side-specific VCC/GND plus SDA/SCL; exact cable side follows board connector, source: Adafruit Learn pinouts |
Pin details
5 connections- VCC
Power pin for each side of the isolator. Adafruit states each isolated side must be powered separately.
PowerVoltage · 3 to 5 VDC on both isolated sides, source: Adafruit Learn pinouts - GND
Ground reference for each side of the isolator. Connect the reference ground on either side.
Ground - SCL
I2C clock line on either isolated side. Adafruit notes a 10K pullup to that side's VCC.
I2CVoltage · Pulled up to that side's VCC, source: Adafruit Learn pinouts - SDA
I2C data line on either isolated side. Adafruit notes a 10K pullup to that side's VCC.
I2CVoltage · Pulled up to that side's VCC, source: Adafruit Learn pinouts - STEMMA QT
STEMMA QT / Qwiic connectors on either side for I2C dev boards and accessories.
UnknownVoltage · Carries side-specific VCC/GND plus SDA/SCL; exact cable side follows board connector, source: Adafruit Learn pinouts
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