> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt # Adafruit ADG728 1-to-8 Analog Matrix Switch - Stemma QT **Type:** Product page · **SKU:** ADA5899 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia) **Page:** https://core-electronics.com.au/adafruit-adg728-1-to-8-analog-matrix-switch-stemma-qt.html ([markdown](https://core-electronics.com.au/adafruit-adg728-1-to-8-analog-matrix-switch-stemma-qt.html.md)) Analog switches are a solid state alternative to relays, when you want a smaller, lower-power technology that won't wear out mechanically. And, as the... ## Pricing - **Price:** $17.30 (inc GST) — $15.73 AUD, exc GST - **Quantity discounts:** 10+ $15.25 (exc GST) · 50+ $14.95 (exc GST) ## Availability & dispatch - Available with a lead time — expect dispatch between Sep 08 and Sep 14. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=ADA5899:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart. - **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/ADA5899:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.) - **Checkout** is completed on-site and includes a captcha at the payment step. 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 Analog switches are a solid state alternative to relays, when you want a smaller, lower-power technology that won't wear out mechanically. And, as the name implies, you can use the **Adafruit ADG728 1-to-8 Analog Matrix Switch** to connect between eight analog signals, much like a set of 8 mechanical switches. These chips tend to be tiny surface mount parts, so this breakout will let anyone use the ADG728 switch for signals up to 5V, without fiddly soldering. The ADG728 uses I2C to select which of the 8 channels switches to turn on or off, to connect that channel to the single analog 'D' pin Note that unlike digital switches and multiplexers, these are not 'input' and 'output' because the signal is bidirectional. You could have the D signal be an input to 8 outputs, or the 8 inputs to one output. Also, the ADG728 isn't really a 'selecting multiplexer', **its a matrix switch with 8 independent switches**. That means that yes, you could treat it like an SP8T where you select which signal is routed to the D pin, you can also turn on multiple switches to 'merge' the signals together. Unlike a relay or mechanical switch, analog switches don't wear out, and the switch time is near instant, about 100nS. The ADG728 chip also guarantees break-before-make so the deselected switches will open before selected switches close. However, there's a few things to watch out for: - **The Vin power pin** (the red wire if using a STEMMA QT cable) **must as high as the highest analog voltages you want to switch**. That means if the analog signals are no more than 5VDC, the V+ pin must be higher than 5V. You cannot power this pin with 3.3V and switch 5V signals. - **It cannot switch signals below ground**. No negative voltages can be applied to the Switch or D pins! - **Analog switches are for signals, not power!** Since this is not a mechanical switch, the signals pass through circuitry that is not designed to source or sink current. This is great for analog signal voltages, and is not good for providing more than a few mA of current. In addition to the 8 switch S pins and the D pin that can be switched to, there's also two I2C address pins so you can change the default address from 0x4C up to 0x4F. There's also a reset pin if you want to immediately set all the switches to open. To get you going fast, Adafruit spun up a custom-made PCB in the[ **STEMMA QT** form factor](https://core-electronics.com.au/search?q=stemma%20qt%20sensor), making it easy to interface with. The [STEMMA QT connectors](https://learn.adafruit.com/introducing-adafruit-stemma-qt/what-is-stemma-qt) on either side are compatible with the [SparkFun Qwiic](https://core-electronics.com.au/catalogsearch/result/?q=qwiic) I2C connectors. This allows you to make solderless connections between your development board and the ADG or to chain it with a wide range of other sensors and accessories using a [**compatible cable**](https://core-electronics.com.au/search?q=stemma%20qt%20cable). ## Technical Details **ADG728 Specifications** - I2C Interface - 2.7 V to 5.5 V Single Supply - 2.5 O On Resistance - 0.75 O On-Resistance Flatness - 100 pA Leakage Currents - Single 8-to-1 Matrix Switch - Power-On Reset - [Datasheets & App notes at Analog Devices](https://www.analog.com/en/products/adg728.html) Product Dimensions: 30.6mm x 17.8mm x 4.7mm / 1.2" x 0.7" x 0.2" Product Weight: 2.1g / 0.1oz ![RoHS 2 2011 65 EU Compliant](https://core-electronics.com.au/attachments/localcontent/RoHS2_2011_65_EU_7356c5574c.svg)![RoHS 2 2015 863 EU Compliant](https://core-electronics.com.au/attachments/localcontent/RoHS2_2015_863_EU_86773f57f9.svg) ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/A/D/ADA5899-1.jpg)