The MAX3421E USB peripheral/host controller contains he digital logic and analog circuitry necessary to mplement a full-speed USB peripheral or a full-/low speed host compliant to USB specification rev 2.0. A built-in transceiver features ±15kV ESD protection and programmable USB connect and disconnect. An inter nal serial interface engine (SIE) handles low-level USB protocol details such as error checking and bus retries The MAX3421E operates using a register set accessed by an SPI™ interface that operates up to 26MHz. Any SPI master (microprocessor, ASIC, DSP, etc.) can add USB peripheral or host functionality using the simple 3 or 4-wire SPI interface. The MAX3421E makes the vast collection of USB peripherals available to any microprocessor, ASIC, o DSP when it operates as a USB host. For point-to-poin solutions, for example, a USB keyboard or mouse inter aced to an embedded system, the firmware that oper ates the MAX3421E can be simple since only a argeted device is supported. nternal level translators allow the SPI interface to run a a system voltage between 1.4V and 3.6V. USB-timed operations are done inside the MAX3421E with inter upts provided at completion so an SPI master does no need timers to meet USB timing requirements. The MAX3421E includes eight general-purpose inputs and outputs so any microprocessor that uses I/O pins to mplement the SPI interface can reclaim the I/O pins and gain additional ones. The MAX3421E operates over the extended -40°C to +85°C temperature range and is available in a 32-pin TQFP package (5mm x 5mm) and a 32-pin TQFN pack age (5mm x 5mm).