Microchip USB3740B-AI2-TR: A Comprehensive Overview of the USB 2.0 Hub Controller
The Microchip USB3740B-AI2-TR is a highly integrated, low-power, and cost-effective 4-port USB 2.0 hub controller designed to meet the demanding requirements of modern computing and consumer electronic applications. This hub controller provides a seamless solution for expanding a single USB host connection into four downstream ports, supporting a mix of high-speed (480 Mbps), full-speed (12 Mbps), and low-speed (1.5 Mbps) devices.
Key Features and Architectural Design
At the heart of the USB3740B lies a robust architecture built for performance and reliability. A dedicated Serial Interface Engine (SIE) handles all USB protocol functions, including packet decoding, error checking, and data signaling, ensuring full compliance with the USB 2.0 specification. The controller incorporates a highly integrated design that requires minimal external components, notably featuring an on-chip 5V-to-3.3V and 5V-to-1.2V voltage regulator, which significantly reduces the Bill of Materials (BOM) and simplifies PCB layout.
A critical feature of this hub is its support for MultiTRAK™, a proprietary technology comprising multiple transaction translators. This architecture provides a dedicated transaction translator for each downstream port, dramatically improving overall bandwidth efficiency. Unlike hubs with a single transaction translator, which can create bottlenecks when multiple full-speed devices are active simultaneously, the MultiTRAK™ technology allows concurrent transactions, ensuring that the performance of one connected device does not degrade the performance of others.
Flexible Configuration and Power Management
The USB3740B offers extensive configuration options to tailor its operation to specific system needs. It supports both battery charging detection (using the BCD methodology) and port power management for controlling downstream power. The controller can be configured via strapping pins or through an attached serial EEPROM, allowing OEMs to customize parameters such as vendor ID (VID), product ID (PID), port disable/enable states, and LED behavior without firmware development.
Its advanced power management capabilities include individual or ganged power control for each downstream port and support for both bus-powered and self-powered modes. The device itself is optimized for ultra-low power consumption, making it an ideal choice for portable and bus-powered applications.
Application Notes and Implementation
Successful implementation of the USB3740B hinges on careful PCB design and layout. Application notes emphasize the importance of proper decoupling capacitor placement near the VREGIN and VDD33 pins to ensure stable power delivery and minimize noise. Furthermore, to maintain signal integrity for high-speed USB data lines, it is crucial to route the differential pairs (DP/DM) with consistent impedance (90Ω ±10%), minimize via usage, and avoid crossing split planes or other noisy signal traces.
The hub also supports various downstream port configurations, including non-removable port identification, which is essential for embedded systems where the ports are permanently connected to internal devices. The inclusion of over-current (OC) detection input pins for each port provides robust protection for the hub and connected peripherals against fault conditions.
ICGOOODFIND: The Microchip USB3740B-AI2-TR stands out as a superior solution for USB port expansion due to its highly integrated design, which lowers system cost and simplifies design-in. Its defining MultiTRAK™ technology ensures superior data throughput in multi-device environments, a critical advantage over competitors. Its flexible configuration via EEPROM and excellent power management make it exceptionally versatile for a wide range of applications, from desktop docks and monitors to industrial control systems and embedded computing.
Keywords: USB 2.0 Hub Controller, MultiTRAK™ Technology, Port Power Management, Battery Charging Detection, Signal Integrity.
