Microchip MCP3901 16位MCU ADC评估方案

Microchip 公司的MCP3901是双路模拟前端(AFE),包括有两个同步取样的16/24位Delta-Sigma ADC,两个PGA(可编增益到32V/V),相位延迟补偿电路,内部基准电压(温度漂移12 ppm/℃),调制器输出电路以及高速20Mz SPI兼容串行接口. MCP3901每路的SINAD为91dB,THD为-104dBc,SFDR为109dB,可编程取样速率高达64ksps,两个通路的串扰为-133dB,关断模式电流小于2uA,主要用在能量计量和功率测量,汽车电子,手提仪表,医疗和电源监视.本文介绍了MCP3901主要特性和功能方框图,时钟框图,以及ADC评估板的主要特性, 电路图与材料清单.

The MCP3901 is a dual channel analog front end (AFE) containing two synchronous sampling delta-sigma Analog-to-Digital Converters (ADC), two PGAs, phase delay compensation block, internal voltage reference, modulator output block, and high-speed 20 MHz SPI compatible serial interface. The converters contain a proprietary dithering algorithm for reduced idle tones and improved THD.

The internal register map contains 24-bit wide ADC data words, a modulator output byte as well as six writable control registers to program gain, over-sampling ratio, phase, resolution, dithering, shutdown, reset and several communication features. The communication is largely simplified with various continuous read modes that can be accessed by the DMA of a MCU and with separate data ready pin that can directly be connected to an IRQ input of a MCU.

The MCP3901 is capable of interfacing to a large variety of voltage and current sensors including shunts, current transformers, Rogowski coils, and Hall effect sensors.

MCP3901主要特性:

• Two synchronous sampling 16/24-bit resolution Delta-Sigma A/D Converters with proprietary multi-bit architecture

• 91 dB SINAD, -104 dBc THD (up to 35th harmonic), 109 dB SFDR for each channel

• Programmable data rate up to 64 ksps

• Ultra low power shutdown mode with <2 μA

• -133 dB Crosstalk between the two channels

• Low Drift Internal Voltage Reference: 12 ppm/°C

• Differential Voltage Reference Input Pins

• High Gain PGA on each channel (up to 32 V/V)

• Phase Delay Compensation between the two channels with 1 μs time resolution

• Separate Modulator outputs for each channel

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

• Independent analog and digital power supplies 4.5V-5.5V AVDD, 2.7V-5.5V DVDD

• Low Power consumption (14 mW typical at 5V)

• Available in small 20-lead QFN and SSOP packages

• Industrial Temperature Range -40℃to +85℃

MCP3901应用:

• Energy Metering & Power Measurement

• Automotive

• Portable Instrumentation

• Medical and Power Monitoring

图1.MCP3901功能方框图
图2.MCP3901时钟图

16位MCU用的MCP3901 ADC评估板

MCP3901 ADC Evaluation Board for 16-Bit MCUs

The MCP3901 ADC Evaluation Board for 16-Bit MCUs system provides the ability to evaluate the performance of the MCP3901 dual channel ADC. It also provides a development platform for 16-bit PIC based applications, using existing 100-pin PIM systems compatible with the Explorer-16 and other high pincount PIC demo boards.The system comes with programmed dsPIC33FJ256GP710 PIM modules that communicate with LabView GUI for data exchange and ADC setup.

MCP3901 ADC评估板特性亮点:

• Dual ADC MCP3901 output display using Serial communication to PC Software Interface

• Simultaneous 4 ksps at 90 dB SINAD and top speed 55 ksps performance on dual MCP3901 channels

• 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 MCP3901 devices. Separate power supplies and power planes - 4 layer board

• PICtail Plus connectors for Explorer-16 daughter board compatibility


图3.MCP3901 ADC评估板布局图

图4.MCP3901 ADC评估板电路图(1)


图5.MCP3901 ADC评估板电路图(2)


图6.MCP3901 ADC评估板电路图(3)

图7.MCP3901 ADC评估板电路图(4)


图8.MCP3901 ADC评估板电路图(5)

MCP3901 ADC评估板材料清单: