The MCP23017 16-bit expander.
When building digital communications systems, there are various protocols to choose from for transferring data between processors and controllers, and peripheral devices. Common options include serial-peripheral interface (SPI) and inter integrated controller (I2C). In addition, extending or expanding the number of signals available is necessary for many applications to improve capability or functionality.
Microchip Technology, an industry leader in developing microprocessors and other semiconductor devices, also supplies the industry with expander ICs that leverage these data control and communication protocols. One component that meets the need of engineers and designers for reliable and flexible input/output extension is the MCP23017 16-bit expander. There are several options for implementing this component, which is described in detail in the MCP23017 datasheet.
MCP23017 I/O Expander Features
The MCP23017 and its SPI alternative, the MP23S17, are AEC-Q100 – a standard that certifies a device’s ability to handle mechanical stress–qualified general purpose I/O expanders that have the following features:
- 16-bit bi-directional I/O expansion
- High-speed interface capability
- MCP23017: 100 kHz, 400 kHz and 1.7 MHz (I2C)
- MCP23S17: 10 MHz (SPI)
- Configurable interrupt source
- Configurable interrupt outputs
- Up to eight bus devices capability
- 1 µA Standby current
- Operation at three different voltage levels:
- 1.8 V – 5.5 V
- 2.7 V – 5.5 V
- 4.5 V – 5.5 V
The MCP23017 is commonly used in automotive applications. However, its design and specifications enable it to be utilized in a wide range of applications where serial communication is employed.
Using the MCP23017 Datasheet
The MCP23017 datasheet is quite extensive. It includes important data to help you leverage the component’s capabilities in your design. This includes layout, functionality, and design constraint data.
Layout and Functionality
The MCP23017 consists of I/O ports, storage registers, data processing, logic and control circuitry, as shown below.
MCP23017 block diagram
The pinout and pin descriptions for the device are shown below.
Pinouts of the MCP23017 16-bit expander
Pin descriptions of the MCP23017 16-bit expander
Below are the electrical and thermal maximum ratings from the MCP23017 datasheet.
MCP23017 maximum ratings
The table below provides ranges for electrical characteristics to guide your design.
DC electrical characteristics of the MCP23017
The MCP23017 datasheet information above is essential for effectively utilizing the MCP23017 for circuit design and schematic capture. For the PCB layout, however, there are options from which you must choose, as discussed below.
PCBA Design with the MCP23017
The MCP23017 datasheet provides important landing pattern data for the several available package options shown below.
As the table above shows, the Microchip offers several options that provide design flexibility when using the MCP23017. However, creating your footprints manually, either from scratch or a generic library symbol, is not advisable. Failing to do so accurately can result in excessive development time and unnecessary costs. A better alternative is to rely on a trusted online parts procurement resource for your components, which can deliver manufacturer-vetted CAD models and data, as shown below.
MCP23017 SOIC CAD models
Combining essential information from the MCP23017 datasheet with reliable component CAD data and models is the best way to ensure a successful design.
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