MAX1557

• USB-to-I²C/SPI/GPIO Interface
• Small PCB area
• Pmod-Compatible Form Factor

The USB2GPIO# adapter board is designed to work with Maxim’s Munich GUI and to connect to various EV kit or Pmod boards with Pmod™ compatible connectors for I²C/SPI/GPIO communication to test and evaluate different Maxim ICs. This document explains how the USB2GPIO# adapter board receives commands from a laptop through the USB to create an I²C/SPI/GPIO interface. The Maxim USB2GPIO# board requires the Munich GUI which can be downloaded from Maxim’s website free of charge.

The USB2GPIO# design is powered directly from the USB bus power (5V) and integrates two low-power, 1.2A, PWM step-down DC-DC converters (MAX1556) to provide programmable V_CC voltages of 1.8V, 2.5V, 3.3V, or 5.0V. A dual, high-speed, USB-to-multipurpose UART/FIFO IC (FT2232HQ), high-speed USB switches (MAX4983), and a 4K MICROWIRE-compatible serial EEPROM are the other ICs on this adapter board.

USB2GPIO# is designed to supersede USB2PMB1# and USB2PMB2# adapters and includes two connectors; connector X3 is a 12-pin connector which supports either I²C with 6 GPIO pins, or SPI with 4 GPIO pins, and is fully compatible with previous adapters and low-pin count EV kit or Pmod boards. This connector is controlled from the Munich GUI. The addition of another connector, X2, which is a 20-pin connector allows either 16 extra GPIO connections or a second SPI port and 12 extra GPIO connections. This 20-pin connector is NOT controlled by Munich GUI but is for use with future EV kits and will be controlled by the relevant EV kit GUIs.

This USB2GPIO# adapter board can be used to enable USB-to-I²C/SPI interface for any Pmod-compatible plug-in peripheral modules such as the Maxim MAX14001PMB#, and MAXREFDES12 – Corona reference designs. In addition, it can be ordered together as an evaluation system (EV system) with different EV kits, such as MAX14001EVKIT#. Note that an “EV system” is an EV kit combined with an interface board, such as a USB2GPIO# and EV kit GUI software. Ordering information for EV systems is included in the EV kits’ corresponding data sheet. Refer to the appropriate EV kit data sheet for quick start and detailed operating instructions.

The USB2GPIO# has been tested on Windows^® 7, Windows 8, and Windows 10 system using Munich GUI, Version 2.17 or later.

Applications

• Cell Phones/Smartphones
• Digital Cameras and Camcorders
• Handheld Instruments
• PDAs and Palmtop Computers
• Portable MP3 and DVD Players

• Up to 97% Efficiency
• 95% Efficiency at 1mA Load Current
• 1MHz PWM Switching Frequency
• Tiny Inductors
• Pin-Selectable Output Voltages
  • MAX1556: 3.3V, 2.5V, 1.8V, and Adjustable
  • MAX1557: 1.5V, 1.3V, 1.0V, and Adjustable
• 1.2A Guaranteed Output Current (MAX1556)
• Voltage Positioning Optimizes Load-Transient Response
• Low 16µA Quiescent Current
• Low 27µA Quiescent Current in Dropout
• Low 0.1µA Shutdown Current
• Analog Soft-Start with Zero Overshoot Current
• Small, 10-Pin, 3mm x 3mm TDFN Package
• Fully Assembled and Tested

The MAX1556 evaluation kit (EV kit) is a fully assembled and tested circuit board that evaluates the MAX1556 and MAX1557 PWM step-down DC-DC converters. The circuit operates from 2.6V to 5.5V. The MAX1556 delivers up to 1.2A and has pin-selectable 1.8V, 2.5V, 3.3V, and adjustable output. The MAX1557 delivers up to 600mA and has pin-selectable 1V, 1.3V, 1.5V, and adjustable output. Each circuit features an on-board shutdown control.

Applications

• Cell Phones/Smartphones
• Digital Cameras and Camcorders
• Handheld Instruments
• PDAs and Palmtop Computers
• Portable MP3 and DVD Players