# Adafruit TCA9548A 1-to-8 I2C multiplexer (#2717): 17.78 × 30.48 mm board and 2 mounting holes

> What are the Adafruit TCA9548A (product 2717) breakout dimensions and mounting-hole positions?

- Category: Electronic components › Modules, sensors & displays
- Kind: Modern device
- Basis: Adafruit's EagleCAD board file for the TCA9548A I2C multiplexer breakout, including its own dimension lines.
- Page: https://xemstudio.com/objects/adafruit-tca9548a-2717/ · JSON: https://xemstudio.com/api/geometry?object=adafruit-tca9548a-2717 · Plain text: https://xemstudio.com/objects/adafruit-tca9548a-2717/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 30.48 | 17.78 | 1.6 |

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- Board 17.78 × 30.48 with square corners, centred, board bottom at 0. Board thickness 1.6 is assumed (Adafruit's board file does not state it); everything else is from the board file.
- Two plated Ø2.5 mounting holes on the long centre line at (0, ±12.70): 25.40 apart, 2.54 in from each short edge.
- No STEMMA QT connectors on this SKU (2717); Adafruit's STEMMA QT I2C mux is a different board (PCA9548, product 5626).
- Not modelled: the two loose 1×12 0.1 in headers along the long edges, the TSSOP-24 chip and passives.
- All dimensions are exact nominal millimetres, true size, with no tolerance added.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| Mounting holes | 2 × Ø2.5, 25.40 apart on the centre line | M2.5 or #2-56 screws and standoffs | designed | all |
| Header rows | 2 × 1×12 at 2.54 pitch along the long edges | 0.1 in female headers or breadboard | designed | all |

## Sizes

| hole | x (mm) | y (mm) | diameter (mm) |
|---|---|---|---|
| 1 | 0 | -12.70 | 2.5 |
| 2 | 0 | +12.70 | 2.5 |

## Where the files are

- Adafruit: [TCA9548A I2C Multiplexer (#2717)](https://www.adafruit.com/product/2717) — web — Publisher's page; dimensions are facts
- Adafruit: [Adafruit-TCA9548A-I2C-Multiplexer-PCB repository](https://github.com/adafruit/Adafruit-TCA9548A-I2C-Multiplexer-PCB) — web — Publisher's page; dimensions are facts
- Adafruit Learning System: [Adafruit TCA9548A 1-to-8 I2C Multiplexer Breakout guide](https://learn.adafruit.com/adafruit-tca9548a-1-to-8-i2c-multiplexer-breakout) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/adafruit-tca9548a-2717/index.json

- adafruit-tca9548a-2717: [STEP](https://xemstudio.com/files/hardware/adafruit-tca9548a-2717/adafruit-tca9548a-2717.step) · [STL](https://xemstudio.com/files/hardware/adafruit-tca9548a-2717/adafruit-tca9548a-2717.stl) — Adafruit TCA9548A 1-to-8 I2C multiplexer (#2717): 17.78 × 30.48 mm board and 2 mounting holes

## Questions

**How big is the Adafruit TCA9548A breakout?**

17.78 × 30.48 mm, 1.6 mm board (assumed).

**Where are its mounting holes?**

Two Ø2.5 holes on the long centre line, 25.40 mm apart (2.54 mm from each short edge).

**Does it have STEMMA QT connectors?**

No. Product 2717 has only 0.1 in header pads; the STEMMA QT mux is the PCA9548 board, product 5626.

## Fits with

- [Adafruit STEMMA QT sensor breakouts (BME280, BNO055/085, VL53, SCD-40, AHT20, SHT40, IMUs, light, magnet, RTC…)](https://xemstudio.com/objects/adafruit-stemma-qt-breakouts/)
- [2.54 mm pin headers, 1×2 to 2×20, vertical and right-angle](https://xemstudio.com/objects/pin-headers-2.54mm/)
- [Threaded standoffs, M2.5 and M3 (hex and round)](https://xemstudio.com/objects/threaded-standoffs-metric/)
- [Adafruit ADS1115 16-bit ADC breakout (1085, STEMMA QT): 25.4 × 17.78 mm board and mounting holes](https://xemstudio.com/objects/adafruit-ads1115-1085/)
- [Adafruit PCA9685 16-channel PWM servo driver](https://xemstudio.com/objects/adafruit-pca9685-16-channel-pwm-servo-driver/)