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MCP3901 Analog Front End
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4. Functional Block Diagram OSC1/CLKI OSC2 PGA 2.4V V REF SINC 3 Filter SPI Serial Interface PGA SINC 3 Filter Clock / Phase Correction Modulator Output MDAT0 MDAT1 CS SCK SDO SDI DR RESET CH0+ CH0- CH1+ CH1- V REF + V REF - DV DD DGND AV DD AGND
5. MCP390x Product Family Comparison MCP3901 MCP3905A MCP3906A MCP3905L MCP3909 Bipolar Input for Negative AC Voltages (Shunt Compatible) X X X X X PGA 16:1 X X X PGA 32:1 X X Active Power Calculation Block X X X X ADC w/ 500:1 Dynamic Range X X X ADC w/ 1000:1 Dynamic Range X X SPI Interface for PIC X X No Load Threshold X X X X X Internal V REF w/ 15 ppm/°C X X X X X Reduced Pulse Width Out for Low Power X
6. MCP390x Product Family Comparison MCP3901 MCP3421/2/3/4 MCP3425/6/7/8 MCP3550/1/3 Number of channels 2 Differential (simultaneous sampling) 1/2/2/4 Differential 1/2/2/4 Differential 1 Differential Resolution 16/24-bit 18-bit 16-bit 22-bit Sampling rate 64,000 sps 4 sps 15 sps 15/15/60 sps PGA gain 32 8 8 N/A INL 15 ppm 10 ppm 10 ppm 2 ppm Supply current (typ.) 2350 µA 135 µA 145 µA 100 µA Interface SPI I 2 C™ I 2 C™ SPI Internal V REF Yes Yes Yes No
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12. MCP3901 Features/Benefits/Results Feature Benefits Results 91 dB SINAD High accuracy measurements Application meets/exceeds accuracy requirements Low AI DD of 2.1 mA typ. Low power consumption Application meets power budget requirements Dual PGA gains of 1:32 Ability to measure small signals Lower cost and small signal sensors can be used 16-bit and 24-bit resolution modes Ability to get additional bits of resolution More accurate results obtained for application 64 ksps in current boost mode High sample rates with additional current boost High sample rates while keeping low power at lower sample rates Phase delay compensation block Adjust for phase delay between multiple MCP3901 devices Corrects phase delay for multi-phase energy measurement
13. MCP3901 Part Numbering MCP3901A0T-I/SS MCP: Microchip Peripheral Package: SS = 20-lead SSOP Part Type (MCP3901): Temp: I = -40°C to +85°C T&R These packages are Lead-free! Address A0
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Hinweis der Redaktion
Welcome to the training module on MCP3901 Analog Front End.
This training module will introduce MCP3901 analog front end and its key advantages.
The MCP3901 feature two delta-sigma A/D converters with adjustable 16-bit and 24-bit resolution modes. Both channels have PGAs with gains up to 32. The MCP3901 operates at a very low power consumption of only 14mW at 5V. The MCP3901 can measure high frequency signals with its adjustable sample rate up to 64 Kilo Samples Per Second . The phase delay compensation block corrects for phase delay in multi-phase energy measurement applications. The MCP3901 also has an internal voltage reference. For communication with a microcontroller , the MCP3901 has a Serial Peripheral Interface interface that operates down to 2.7V for compatibility with 3V microcontroller s.
This block diagram shows the basic blocks of the MCP3901. The inputs for both ADC channels are shown with the PGAs and delta-sigma converters. Note the internal voltage reference, phase correction block and modulator output pins.
The table shown on this page compares the MCP3901 functionality with the functionality of other energy measurement ICs available from Microchip. Note that the MCP3901 has a relatively wide dynamic range, PGA gain and communicates to MCUs via the Serial Peripheral Interface . In contrast with the energy measurement ICs, the MCP3901 does not have an active power calculation block.
The table shown on this page compares the MCP3901 functionality with the functionality of other delta-sigma A/D converters from Microchip. Note that the MCP3901 has a significantly faster sample rate which accounts for the higher current consumption than the slower A/D converters.
Relative to competing solutions the MCP3901 has adjustable resolution allowing for more accurate measurements to be displayed in the application. The 91 dB Signal In Noise and Distortion, is industry leading in performance. Dual PGAs enable the MCP3901 to be used for many industrial applications.
As mentioned previously, the MCP3901 has a lower power consumption of only 14mW at 5V. The MCP3901 also has an adjustable sample rate up to 64 kilo samples per seconds. In order to maintain low power this high frequency sample rate uses a special current boost mode so that lower sample frequencies do not operate with the same current consumption.
The MCP3901 injects pseudo-random noise that in effect scrambles the conversion process. The result is improved linearity and removal of false signals and correlated noise.
In order to adjust the sample rate versus desired accuracy, the MCP3901 allows for the oversampling ratio to be adjusted. For multi-phase energy measurement applications, phase delay can be corrected between multiple MCP3901 devices using the phase delay compensation block.
In addition to being Serial Peripheral Interface compatible, the MCP3901 has an addressable Serial Peripheral Interface to make easier the communication between multiple MCP3901 devices. This is particularly useful in multi-phase energy measurement applications. For industrial applications using ratiometric sensors the differential internal voltage reference is very useful.
The table displays some of the previously mentioned features and their benefits and results. The focus of these features highlight the overall accuracy and low power operation of the MCP3901 relative to competing solutions.
Here illustrates the ordering information for the MCP3901.
The primary applications for the MCP3901 are for energy measurement. The superior performance and feature set make it ideal for single-phase and three-phase electricity utility metering. In addition, the MCP3901 can be used as a measurement node for power monitoring applications such as power supplies, servers and white goods. Additional applications that can use the MCP3901 as a general purpose A/D converter include some industrial sensor applications and medical applications where high resolution and moderately fast sampling rates are required.
To aid in the evaluation of the MCP3901, the MCP3901 ADC Evaluation Board captures data from the MCP3901 and passes it to a PC to be displayed in a graphical user interface. An online video tutorial is available at microchip.com.
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