The MAX3421E USB peripheral/host controller contains the digital logic and analog circuitry necessary to implement 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 internal 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, or DSP when it operates as a USB host. For point-to-point
solutions, for example, a USB keyboard or mouse interfaced to an embedded system, the firmware that operates the MAX3421E can be simple since only a
targeted device is supported.
Internal level translators allow the SPI interface to run at a system voltage between 1.4V and 3.6V. USB-timed operations are done inside the MAX3421E with interrupts provided at completion so an SPI master does not 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 implement 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 package
(5mm x 5mm).
Key Features
Applications/Uses
Microprocessor-Independent USB Solution
Software Compatible with the MAX3420E USB Peripheral Controller with SPI Interface
Complies with USB Specification Revision 2.0 (Full-Speed 12Mbps Peripheral, Full-/Low-Speed 12Mbps/1.5Mbps Host)
Integrated USB Transceiver
Firmware/Hardware Control of an Internal D+ Pullup Resistor (Peripheral Mode) and D+/D- Pulldown Resistors (Host Mode)
Programmable 3- or 4-Wire, 26MHz SPI Interface
Level Translators and VL Input Allow Independent System Interface Voltage
Internal Comparator Detects VBUS for Self-Powered Peripheral Applications
ESD Protection on D+, D-, and VBCOMP
Interrupt Output Pin (Level- or Programmable-Edge) Allows Polled or Interrupt-Driven SPI Interface
Eight General-Purpose Inputs and Eight General-Purpose Outputs
Interrupt Signal for General-Purpose Input Pins, Programmable Edge Polarity
Intelligent USB SIE
Automatically Handles USB Flow Control and Double Buffering
Handles Low-Level USB Signaling Details
Contains Timers for USB Time-Sensitive Operations so SPI Master Does Not Need to Time Events
Space-Saving Lead-Free TQFP and TQFN Packages (5mm x 5mm)
