AT43USB326-AU

Overview

The AT43USB326-AU is an 8-bit microcontroller based on the AVR RISC architecture, featuring a 16 KB masked ROM and 512 bytes of data SRAM. It integrates a USB hub with one attached port and two external ports, alongside a USB keyboard function with three programmable endpoints. The device operates at 5V with an on-chip 3.3V power supply and utilizes a 6 MHz oscillator with an on-chip PLL to generate a 12 MHz system clock. Key peripherals include 32 general-purpose working registers, 32 programmable I/O pins supporting an 18x8 keyboard matrix, four LED driver outputs, and an 8-bit timer/counter.

Feature Summary

• AVR 8-bit RISC core with 83 ns instruction cycle time and up to 12 MIPS throughput
• Integrated USB Hub with one permanently attached function and two external downstream ports
• USB Keyboard Function with three programmable endpoints (Endpoint 0 plus Endpoints 1 and 2)
• On-chip 3.3V power supplies generating 30 mA each from the 5V input

Applications

• Programmable USB keyboard controllers
• USB hubs with embedded keyboard functionality
• Multimedia USB keyboard interfaces

Procurement Notes

Verify the component status as the AT43USB325E-AU variant is listed as obsolete in some distributor records. Confirm the specific revision level required for your design, as the datasheet references Rev 2006. Ensure that the 48-lead LQFP package dimensions match your PCB footprint requirements before finalizing procurement.

Selection Notes

Select this component when a dedicated USB hub combined with a keyboard controller is required in a single IC. Note that it lacks UART, SPI, and EEPROM, which distinguishes it from standard megaAVR devices like the AT90S8515. It requires a 6 MHz crystal with high Q or low ESR for proper PLL operation and frequency stability better than 100 PPM.

Part Context

The AT43USB326 belongs to the AT43USB series of USB microcontrollers. It shares architectural similarities with the AT90S8515 but replaces standard communication interfaces with specialized USB hardware. The device is designed specifically for applications requiring simultaneous hub management and keyboard HID functionality without external logic.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should verify if newer Microchip AVR families with integrated USB support meet the specific pinout and peripheral requirements, noting that direct pin-compatible replacements may not exist due to the unique hub integration.