原标题：Maxim MAX1358B16位数据采集方案

　　Maxim 公司的MAX1358B是16位数据采集系统,集成了ADC,DAC,UPIO,RTC,电压监视器和温度传感器,单电源+1.8V到+3.6V,具有可编程的转换速率,从10sps到477sps,本身和系统失调和增益校准,可编增益1,2,4或8,单极和双极模式,主要用在电池供电和手提设备,电化学和光学传感器,医疗仪器,工业控制和数据采集系统.本文介绍了MAX1358B主要特性, 功能方框图以及光反射计应用电路图, 电化学测量应用电路, 温度测量, LCD对比度调整, 单端和差分压电蜂鸣器驱动电路等.

　　16-Bit, Data-Acquisition System with ADC, DACs, UPIOs, RTC, Voltage Monitors, and Temp Sensor

　　The MAX1358B smart data-acquisition system (DAS) is based on a 16-bit, sigma-delta analog-to-digital converter (ADC) and system-support functionality for a microprocessor (μP)-based system. This device integrates an ADC, DACs, operational amplifiers, internal selectable- voltage reference, temperature sensors, analog switches, a 32kHz oscillator, a real-time clock (RTC) with alarm, a high-frequency-locked loop (FLL) clock, four user-programmable I/Os, an interrupt generator, and 1.8V and 2.7V voltage monitors in a single chip.

　　The MAX1358B has dual 10:1 differential input multiplexers (muxes) that accept signal levels from 0 to AVDD. An on-chip 1x to 8x programmable-gain amplifier (PGA) allows measuring low-level signals and reduces external circuitry required.

　　The MAX1358B operates from a single +1.8V to +3.6V supply and consumes only 1.15mA in normal mode and only 3μA in sleep mode. The MAX1358B has two DACs with one uncommitted op amp.

　　The serial interface is compatible with either SPI™/QSPI™ or MICROWIRE™, and is used to power up, configure, and check the status of all functional blocks.

　　The MAX1358B is available in a space-saving, 40-pin TQFN package and is specified over the commercial (0℃ to +70℃) and the extended (-40℃ to +85℃) temperatureranges.

　　MAX1358B主要特性:

　　_ +1.8V to +3.6V Single-Supply Operation

　　_ Multichannel, 16-Bit, Sigma-Delta ADC

　　10sps to 477sps Programmable Conversion Rate

　　Self- and System Offset and Gain Calibration

　　PGA with Gains of 1, 2, 4, or 8

　　Unipolar and Bipolar Modes

　　10-Input Differential Multiplexer

　　_ 10-Bit Force-Sense DACs

　　_ Uncommitted Op Amps

　　_ Dual SPDT and SPST Analog Switches

　　_ Selectable References

　　1.25V, 2.048V, and 2.5V

　　_ Internal Charge Pump

　　_ System Support

　　RTC and Alarm Register

　　Internal/External Temperature Sensor

　　Internal Oscillator with Clock Output

　　User-Programmable I/O and Interrupt Generator

　　VDD Monitors

　　_ SPI/QSPI/MICROWIRE, 4-Wire Serial Interface

　　_ Space-Saving (6mm x 6mm x 0.8mm), 40-Pin

　　TQFN Package

　　MAX1358B应用:

　　Battery-Powered and Portable Devices

　　Electrochemical and Optical Sensors

　　Medical Instruments

　　Industrial Control

　　Data-Acquisition Systems

　　图1.MAX1358B功能方框图

　　图2.MAX1358B线性稳压器方框图

　　图3.MAX1358B电荷泵方框图

　　图4.采用双LED和单个光电二极管的光反射计应用电路图

　　图5.电化学测量应用电路图(传统和计数器配置)

　　图6.采用双遥控传感器的温度测量框图

　　图7.LCD对比度调整应用电路图

　　图8.传感器偏置电压调整应用电路图

　　图9.电源睡眠模式逐个周期控制的应用电路图

　　图10.单端压电蜂鸣器驱动电路

　　图11.差分压电蜂鸣器驱动电路