AT43312A-SC

Overview

The AT43312A is a USB hub controller supporting one upstream and four downstream ports, compliant with USB Specification Rev 1.1. It operates at 5V with an on-chip 3.3V regulator, eliminating the need for external voltage sources. The device supports full-speed (12 Mb/s) and low-speed (1.5 Mb/s) data transfers. It functions in either bus-powered or self-powered modes, configurable via the SELF/BUS pin. Electrical specifications include a 5V supply range of 4.4V to 5.25V and an operating temperature range of -40°C to +85°C. The chip integrates a Serial Interface Engine, Hub Repeater, and Hub Controller within 32-lead SOIC or LQFP packages.

Feature Summary

• Supports both bus-powered and self-powered hub operations with individual port power control
• Integrates an on-chip power supply to generate 3.3V from a 5V input
• Provides per-port overcurrent monitoring and connection status indicators
• Handles full-speed and low-speed USB transactions with internal clock generation

Applications

• Standalone USB hubs connecting multiple peripherals to a host
• Add-on hubs integrated into non-USB peripherals such as PC displays
• Keyboard and monitor expansion units requiring USB connectivity

Procurement Notes

Verify package type availability, as the component is offered in 32-lead SOIC and LQFP configurations. Confirm that ordering suffixes do not alter functional characteristics unless explicitly documented by the manufacturer. Ensure compatibility with required crystal frequencies and external capacitor values for proper oscillator and regulator operation.

Selection Notes

Select this controller for designs requiring compliance with USB Spec Rev 1.1. Choose the appropriate package based on board space constraints. Ensure external components meet specified capacitance and resistance values for the CEXT, LFT, and pull-up/pull-down resistors. Verify power switch selection meets voltage drop requirements for the chosen power mode.

Part Context

Manufactured by Microchip Technology, formerly Atmel, the AT43312A serves as a foundational component for USB hub implementations. It replaces discrete logic solutions by integrating protocol handling, signal repeater functions, and power management into a single silicon die. The device simplifies design complexity by managing enumeration and port status reporting internally.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult official Microchip Technology resources for current product line updates or equivalent alternatives.