General Description

The MAX14500–MAX14503 USB-to-SD? card readers provide a means for portable devices that support full speed USB communication (12Mbps) with one or two SD card slots, upgrading the USB SD card reader function to USB Hi-Speed (480Mbps) operation. The MAX14500–MAX14503 have two modes of operation: Pass Thru and Card Reader. In pass thru, the SD and USB signals pass through the MAX14500–MAX14503 without modification, appearing like the device is not

present. The host microprocessor firmware does not need modification, as there is no change from the host microprocessor’s perspective. In Card Reader mode, the MAX14500–MAX14503 implement a Hi-Speed USB card reader that operates independently of the host microprocessor. All the capabilities of the full-speed USB port and SD card slot are preserved with the addi

tional feature that allows a faster way for a PC to read or write to the SD card. The MAX14500–MAX14503 support SD high capacity SDHC cards. The 40-pin TQFN version supports one SD card, while the 56-bump WLP version supports two SD cards.

特性 Features

?USB 2.0 Hi-Speed and Full-Speed Compliant

?SDHC Card Support

?Internal Hi-Speed USB SD Card Reader Eases Host μP Overhead

?On-Chip Termination and Pullup Resistors

?Internal SD Switches Allow For Multiplexing Two SD Cards on a Single-Microprocessor SD Port

?Accommodates Clock Input Frequencies 26MHz, 19.2MHz, 13MHz, and 12MHz

?Internal Clock Squarer for Low-Amplitude TCXO Signals

?No Power-Supply Sequencing Required

?Compatible with +1.8V to +3.3V I/O Host Microprocessor

?Simple Control Mode Requires Only a Single GPIO

?I2C Control Provides Multiple Configuration Options

?I2C Control Required for Two SD Cards

?On-Chip Power-On Reset/Brown-Out Reset