TIADS7924四路12位ADC开辟应用方案

TI 公司的ADS7924是四路带I2C接口的12位模数转换器（ADC），接纳低功耗的ADC核，支持低电压运行以及机动的丈量顺序，模拟电压2.2V 到 5.5V ，数字电压1.65V 到 5.5V，组成完整的监督系统，主要用在手提和以电池为能源的系统如医疗，通信，遥控传感器信号监督，电源监督和能量收集等。本文先容了ADS7924主要特点，方框架图，几种典范的传感器数据收罗应用电路，以及ADS7924EVM评估板主要特点，电路图和质料清单（BOM）。

The ADS7924 is a four-channel, 12-bit, analog-to-digital converter (ADC) with an I²C™ interface. With its low-power ADC core, support for low-supply operation, and a flexible measurement sequencer that essentially eliminates power consumption between conversions, the ADS7924 forms a complete monitoring system for power-critical applications such as battery-powered equipment and energy harvesting systems.

The ADS7924 features dedicated data registers and onboard programmable digital threshold comparators for each input. Alarm conditions can be programmed that generate an interrupt. The combination of data buffering, programmable threshold comparisons, and alarm interrupts minimize the host microcontroller time needed to supervise the ADS7924.

ADS7924主要特点：

Intelligent Monitoring:

Auto-Sequencing of 4-Channel Multiplexer

Individual Alarm Thresholds for Each Channel

Programmable Scan Rate

Micropower Monitoring:

Four-Channel Scanning:

Every 1ms → 25µW

Every 10ms → 5µW

< 1µA of Power-Down Current

Programmable Interrupt Pin Controls Shutdown/Wakeup of the Microcontroller

Auto Power-Down Control

PWRCON Pin Allows Shutdown of External Op Amp

Wide Supply Range:

Analog Supply: 2.2V to 5.5V

Digital Supply: 1.65V to 5.5V

Small Footprint: 3mm × 3mm QFN

ADS7924应用：

Portable and Battery-Powered Systems:

Medical, Communications, Remote Sensor Signal Monitoring, Power-Supply Monitoring Energy Harvesting

图1。ADS7924方框架图

图2。ADS7924和TLV2780缓冲放大器的传感器数据收罗电路图

NOTE: fC3dB BW = 159kHz, R = 1kΩ, and C = 1nF where R = RMUX + RSENSOR + RX.
图3。ADS7924和TLV2780缓冲放大器带滤波器的传感器数据收罗电路图

NOTE: fC3dB BW = 159kHz, R = 1kΩ, and C = 1nF where R = RMUX + RSENSOR + RX, C = CX + CADCIN, RMUX is approximately 60Ω, and CADCIN is approximately 15pF.
图4。ADS7924仅带滤波器的传感器数据收罗电路图

NOTE: fC3dB BW = 159kHz, R = 1kΩ, and C = 1nF where R = RMUX + RSENSOR + RX, and RMUX is approximately 60Ω. Gain = 1 + R1/R2.
图5。ADS7924和TLV2780缓冲放大器带增益设定电阻，滤波器的传感器数据收罗电路图

NOTE: C = 200pF, R = 1kΩ, and the capacitance at the ADCIN pin is approximately 15pF.
图6。ADS7924和TLV2780接纳运放驱动RC滤波器的传感器数据收罗电路图
ADS7924EVM 和ADS7924EVM-PDK

图7。ADS7924EVM（左） 和ADS7924EVM-PDK（右）外形图

ADS7924EVM (Left) and ADS7924EVM-PDK (Right)

This user＇s guide describes the characteristics, operation, and use of the ADS7924EVM, both by itself and as part of the ADS7924EVM-PDK. This evaluation model (EVM) is an evaluation board for the ADS7924, a 12-bit, sampling, low-power, analog-to-digital converter (ADC) with an I2C™ interface. The EVM-PDK allows evaluation of the ADS7924 in some modes of operation, but not all. Complete circuit descriptions, schematic diagrams, and bills of material are included in this document.

ADS7924EVM 和ADS7924EVM-PDK 主要特点：

ADS7924EVM:

• Contains all support circuitry needed for the ADS7924

• Buffer options: Onboard analog input buffer can be bypassed

• Compatible with the TI Modular EVM System

ADS7924EVM-PDK:

• Easy-to-use evaluation software for Microsoft® Windows® XP

• Data collection to text files

• Built-in analysis tools including scope, FFT, and histogram displays

• Complete control of board settings

• Easily expandable with new analysis plug-in tools from Texas Instruments

图8。ADS7924EVM电路图

ADS7924EVM质料清单（BOM）

详情请复制打开此衔接地址：
http://focus.ti.com/lit/ds/symlink/ads7924.pdf
和
http://focus.ti.com/lit/ug/sbau173/sbau173.pdf