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Full machine-readable index: https://core-electronics.com.au/llms.txt # Pololu I²C Isolator with Connectors, ISO1640 **Type:** Product page · **SKU:** POLOLU-5391 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia) **Page:** https://core-electronics.com.au/pololu-i2c-isolator-iso1640-connectors.html ([markdown](https://core-electronics.com.au/pololu-i2c-isolator-iso1640-connectors.html.md)) This module enables galvanically isolated bidirectional I²C communication between two devices. The bidirectionality applies to both SDA and SCL, which... ## Pricing - **Price:** $9.70 (inc GST) — $8.82 AUD, exc GST - **Quantity discounts:** 10+ $8.46 (exc GST) · 25+ $8.20 (exc GST) ## Availability & dispatch - Available with a lead time — expect dispatch between Aug 24 and Aug 27. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=POLOLU-5391:1` (comma-separated SKU:qty pairs) and share the link. 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Share the cart link; checkout takes it from there. - **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works) - **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt ## Description This module enables galvanically isolated (electrically isolated), bidirectional communication between two I²C devices. This isolation means current cannot flow from one side to the other, and incorrect connections or bad voltages on one side cannot propagate through to damage the device connected to other side. The module is based on the TI ISO1640B, which supports bidirectional data transfer up to 1.7 MHz. See the [ISO1640BDR datasheet](https://core-electronics.com.au/attachments/localcontent/iso1640_28738d836ba.pdf) for more information. | \| [![](https://core-electronics.com.au/attachments/localcontent/0J13055_23887e8a3ee.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13055_2317034993d.jpg) \| \|---\| \| Pololu I²C Isolator with Connectors, ISO1640, connected with 4-pin JST SH-style cables (not included). \| | \| [![](https://core-electronics.com.au/attachments/localcontent/0J13053_43870011c14.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13053_47181a35a3b.jpg) \| \|---\|---\| \| Pololu I²C Isolator, ISO1640, on a breadboard (version without connectors shown, headers not included). \| | |---| This module is available [with JST SH-style 4-pin connectors](https://core-electronics.com.au/pololu-i2c-isolator-iso1640-connectors.html) that are compatible with Qwiic and Stemma QT or [without connectors](https://core-electronics.com.au/pololu-i2c-isolator-iso1640-galvanic-isolation.html), as shown on the right above, for more compact installations (cables and male headers are not included). **Details for item #5391** This is the version **with JST SH-style 4-pin connectors**. | \| [![](https://core-electronics.com.au/attachments/localcontent/0J13052_334483a2322.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13052_68828590a1a.jpg) \| \|---\| \| Pololu I²C Isolator, ISO1640. \| | \| [![](https://a.pololu-files.com/picture/0J13060.500.jpg?49993723c27c055a1b7383dcd3ef6411)](https://a.pololu-files.com/picture/0J13060.1200.jpg?49993723c27c055a1b7383dcd3ef6411) \| \|---\|---\| \| Pololu I²C Isolator with Connectors, ISO1640, with dimensions and a Pololu quarter for size reference. \| | |---| **Using the module** | [![](https://a.pololu-files.com/picture/0J13057.460.jpg?444c03e8359754250c853761633f38e0)](https://a.pololu-files.com/picture/0J13057.1200.jpg?444c03e8359754250c853761633f38e0) | |---| | Pinout of the Pololu I²C Isolator with Connectors, ISO1640 (top and bottom views). | Each side must be powered separately: 3 V to 5.5 V should be supplied across **VCC1** and **GND1**, and 2.25 V to 5.5 V should be supplied across **VCC2** and **GND2**. The two sides are galvanically isolated (GND1 is *NOT* connected to GND2). **SDA1** and **SCL1** connect to the I²C data and clock signals of one device while **SDA2** and **SCL2** connect to the I²C data and clock signals of the other. Both the SDA and SCL connections are bidirectional, which allows for clock stretching. There are 10k pull-up resistors from SDA1 and SCL1 to VCC1 and from SDA2 and SCL2 to VCC2; for high-speed communication, external pull-up resistors can be added in parallel as necessary to make the pull-ups stronger. | [![](https://core-electronics.com.au/attachments/localcontent/0J13043_65244f17072.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13043_36966e45ff7.png) | |---| | Schematic diagram of the Pololu I²C Isolator, ISO1640. | **Note:** The two sides of the ISO1640 have different logic thresholds. In particular, SDA1 and SCL1 will only drive as low as 0.5 V to 0.7 V when the corresponding SDA2 or SCL2 are driven low, so it is important to ensure that the device connected to side 1 will recognize 0.7 V as low. In the other direction, SDA2 and SCL2 will drive to between 0 V and 0.4 V when SDA1 and SCL1 are driven low. See the [ISO1640 datasheet](https://core-electronics.com.au/attachments/localcontent/iso1640_28738d836ba.pdf) for more information. **Isolation/clearance considerations** Although the ISO1640 IC has an isolation rating of up to 3 kVRMS, please note that the board is made to be compact, and the tightest clearance (2 mm) is smaller than the 4 mm clearance of the IC package. The picture below shows the regions of tightest clearance (the larger pads are just structural pads for the connectors and are not electrically connected to anything): | [![](https://core-electronics.com.au/attachments/localcontent/0J13058_604547df63f.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13058_22871e79220.jpg) | |---| | The tightest clearance on the Pololu I²C Isolator ISO1640 is between these sets of pads, which are 2 mm apart. | **Dimensions** | Size: | 0.4" × 0.6" × 0.28" | |---|---| | Weight: | 0.6 g | **General specifications** | Minimum operating voltage: | 2.25 V[1](https://core-electronics.com.au/#note1) | |---|---| | Minimum operating voltage: | 3 V[2](https://core-electronics.com.au/#note2) | | Maximum operating voltage: | 5.5 V | | Connectors?: | Y | | Isolated power transfer?: | N | **Identifying markings** | PCB dev codes: | iso02a | |---|---| | Other PCB markings: | 0J15301 | **Notes:** 1Side 2 (VCC2).2Side 1 (VCC1). **File downloads** - **[Dimension diagrams of the Pololu I²C Isolator, ISO1640](https://core-electronics.com.au/attachments/localcontent/pololu-i2c-isolator-iso1640-dimensions_37937a89ca1.pdf) (379k pdf)** - **3D model of the Pololu I²C Isolator, ISO1640 (4MB step)** - **Drill guide for the Pololu I²C Isolator, ISO1640 (15k dxf)** This DXF drawing shows the locations of all of the board’s holes. **Recommended links** - **[TI ISO1640BDR datasheet](https://core-electronics.com.au/attachments/localcontent/iso1640_28738d836ba.pdf)** ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/P/O/POLOLU-5391-1.jpg)