</a>ADC" title="ADC">ADC" title="ADC">ADC,兩個PGA,相位延遲補償區塊,低漂移基準電壓,調制輸出區塊,數字失調和增益誤差校正寄存器以及高速20MHz SPI兼容串口.每路有 94.5 dB SINAD, -106.5 dBc THD, 111 dB SFDR,2.7-3.6V工作電壓,可編數據速率高達125 ksps,主要用在能量和功率測量,汽車,手持儀表,醫療和電源監視以及音/視頻識別.本文介紹了MCP3911主要特性,方框圖以及用于16位MCU的MCP3911 ADC評估板主要特性, 和PIM MCU連接框圖,電路圖,材料清單和PCB元件布局圖.

The MCP3911 is a 2.7V to 3.6V dual channel Analog Front End (AFE) containing two synchronous sampling Delta-Sigma Analog-to-Digital Converters (ADC), two PGAs, phase delay compensation block, low-drift internal voltage reference, modulator output block, digital offset and gain errors calibration registers, and high-speed 20 MHz SPI compatible serial interface.

The MCP3911 ADCs are fully configurable with features such as: 16/24-bit resolution, OSR from 32 to 4096, gain from 1x to 32x, independent shutdown and reset, dithering and auto-zeroing. The communication is largely simplified with the one-byte-long commands including various continuous read/write modes that can be accessed by the Direct Memory Access (DMA) of an MCU, and with a separate data ready pin that can be directly connected to an Interrupt Request (IRQ) input of an MCU.

The MCP3911 is capable of interfacing a large variety of voltage and current sensors including shunts, current transformers, Rogowski coils and Hall effect sensors.

MCP3911主要特性:

• Two Synchronous Sampling 16/24-bit Resolution Delta-Sigma A/D Converters

• 94.5 dB SINAD, -106.5 dBc Total Harmonic Distortion (THD) (up to 35th harmonic), 111 dB SFDR for Each Channel

• 2.7V - 3.6V AVDD, DVDD

• Programmable Data Rate up to 125 ksps

4 MHz Maximum Sampling Frequency

• Oversampling Ratio up to 4096

• Ultra Low Power Shutdown Mode with <2 μA

• -122 dB Crosstalk between the Two Channels

• Low Drift 1.2V Internal Voltage Reference: 7 ppm/℃

• Differential Voltage Reference Input Pins

• High Gain PGA on Each Channel (up to 32V/V)

• Phase Delay Compensation with 1 μs Time Resolution

• Separate Modulator Output Pins for Each Channel

• Separate Data Ready Pin for Easy Synchronization

• Individual 24-bit Digital Offset and Gain Error Correction for Each Channel

• High-Speed 20 MHz SPI Interface with Mode 0,0 and 1,1 Compatibility

• Continuous Read/Write Modes for Minimum Communication

• Low Power Consumption (8.9 mW at 3.3V, 5.6 mW at 3.3V in low-power mode, typical)

• Available in Small 20-lead QFN and SSOP Packages, Pin-to-pin Compatible with MCP3901

• Extended Temperature Range: -40℃ to +125℃

MCP3911應用:

• Energy Metering and Power Measurement

• Automotive

• Portable Instrumentation

• Medical and Power Monitoring

• Audio/Voice Recognition

圖1.MCP3911方框圖

用于16位MCU的MCP3911 ADC評估板

MCP3911 ADC Evaluation Board for 16-Bit MCUs

The MCP3911 ADC Evaluation Board for 16-Bit MCUs system provides the opportunity to evaluate the performance of the MCP3911 dual-channel ADC. It also provides a development platform for 16-bit PIC®-based applications, using existing 100-pin PIC microcontroller Plug-in Module (PIM) systems that are compatible with the Explorer 16 and other high pin count PIC®-based demo boards. The system comes with a programmed PIC24FJ256GA110 PIM module that communicates with the Energy Management Utility software for data exchange and ADC setup.

MCP3911 ADC評估板亮點:

• Dual ADC MCP3911 output display using serial communication to the PC software interface

• Simultaneous 55 ksps at OSR32 address loop ALL or 95 dB SINAD at OSR512 performance on MCP3911

• System and ADC performance analysis through graphical PC tools showing noise histogram, frequency domain (FFT), time domain scope plot, and statistical numerical analysis

• Robust hardware design with analog grounding and analog/digital separation, allowing low noise evaluation of MCP3911 devices; includes separate power supplies and power planes on a 4-layer board.

• PICtail™ Plus connectors for Explorer 16 daughter board compatibility



圖2.MCP3911評估板外形圖

圖3.MCP3911和PIM MCU連接框圖

圖4.MCP3911評估板電路圖:ADC和電源

圖5.MCP3911評估板電路圖:MCU

圖6.MCP3911評估板電路圖:PIM模塊

圖7.MCP3911評估板電路圖:LCD和UART
MCP3911評估板材料清單:



圖8.MCP3911評估板PCB布局圖:頂層

圖9.MCP3911評估板PCB布局圖:底層

圖10.MCP3911評估板元件布局圖:頂層

圖11.MCP3911評估板元件布局圖:底層
詳情請見:
http://ww1.microchip.com/downloads/en/DeviceDoc/22286A.pdf
和
http://ww1.microchip.com/downloads/en/DeviceDoc/52033A.pdf