Designing with the Microchip USB2517 7-Port USB 2.0 Hi-Speed Hub Controller

The Microchip USB2517 is a highly integrated 7-port USB 2.0 hub controller designed to provide robust and flexible connectivity solutions for a wide range of applications. Its primary role is to expand a single upstream USB port into seven downstream ports, supporting full Hi-Speed (480 Mbps), Full-Speed (12 Mbps), and Low-Speed (1.5 Mbps) operations. This makes it an indispensable component in modern computing systems, industrial setups, and embedded designs where multiple USB peripherals must operate simultaneously from a single host connection.

A key strength of the USB2517 lies in its advanced feature set that simplifies design-in and enhances end-product reliability. The hub incorporates MultiTRAK™, a technology featuring multiple transaction translators. This architecture is critical for maintaining high bandwidth efficiency. By having a dedicated transaction translator for each downstream port, it prevents a single bandwidth-intensive device (like a video camera) from monopolizing the hub's resources and degrading the performance of other connected devices. This ensures consistent, high-speed data transfer across all ports.

Furthermore, the hub supports FlexConnect, a unique feature that allows for port swapping. This enables the system designer to designate one downstream port as the upstream port and vice versa, providing exceptional flexibility in system architecture, particularly for embedded systems with non-standard physical configurations.

From a design perspective, the USB2517 significantly reduces both board space and Bill of Materials (BOM). It integrates USB 2.0 hub functionality with all necessary termination resistors on a single chip. It requires only a single 24 MHz crystal or oscillator and minimal external components to operate. The device is also offered in a compact, RoHS-compliant 64-pin QFN package, ideal for space-constrained applications.

Power management is another area where the USB2517 excels. It offers comprehensive per-port or ganged power switching and programmability. Each downstream port can be individually controlled and configured for power switching and over-current detection. This granular control is vital for managing power distribution in systems with a mix of high-power (e.g., hard drives) and low-power (e.g., keyboards) devices, ensuring compliance with USB power delivery specifications and enhancing overall system safety.

The device is also fully compliant with the USB Battery Charging Specification Revision 1.2. This means it can detect charging downstream ports (CDP) or dedicated charging ports (DCP), allowing connected devices like smartphones and tablets to charge at their maximum possible rate, even when the host computer is in a low-power state or turned off. This is a highly valued feature in modern docking stations and monitors.

Configuration of the USB2517 is straightforward. It can operate in a plug-and-play mode using its internal default settings stored on a one-time programmable (OTP) ROM. For greater customization, designers can use an external Serial PROM (EEPROM) or an I2C/SMBus master to configure various parameters, including vendor ID, product ID, port descriptors, and manufacturing strings. This flexibility allows a single hardware design to be easily tailored for different customers or market segments.

In summary, the Microchip USB2517 provides a powerful, feature-rich, and cost-effective foundation for implementing robust USB hub functionality. Its combination of high performance, integrated features, and design flexibility makes it a top choice for engineers.

ICGOODFIND: The USB2517 stands out for its MultiTRAK™ multi-transaction translator architecture, which ensures superior bandwidth management, and its integrated power management and battery charging support, making it an optimal and future-proof solution for complex USB hub designs.

Keywords: USB 2.0 Hub, MultiTRAK™, Battery Charging, Power Management, FlexConnect.