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how to add opamp buffer to full differential adc mcp3301

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raman00084

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MCP3301 measuring +-5v with respect to ground

by reading the data sheet of mcp3301 if i give +5v on IN+(2 PIN) AND ground on IN-(3 PIN) the adc will read +4096

same way if i give -5v on IN-(2PIN) AND ground on IN-(3pin) the adc will read -4096

this is right kindly help
 

anti aliasing filter for full deferential ADC MCP3301

how to put anti aliasing filter for full deferential ADC MCP3301 it has 2 ends. should i must use dual power supply + and - are single power supply for aliasing .
 

how to add op amp buffer to full differential adc mcp3301. wheather i must use dual +- power supply? is lm358 is good .
 


Re: MCP3301 measuring +-5v with respect to ground

Please observe the "Absolute Input Voltage" specification in datasheet. It says clearly that the voltage at both differential pins must be positive. To process negative input voltage, you need an external differential amplifier.
 

Re: MCP3301 measuring +-5v with respect to ground

can you suggest any ckt. my input is like this my sensor is load cell with signal conditioner unit from the unit i will get +10v with respect to ground if i apply 5000 kg push force and -10v with respect to ground if i apply 50000 kg pull force
 
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Re: MCP3301 measuring +-5v with respect to ground

the difference amplifier in the ckt is between +10 and - 10v ,but mine is with respect to ground it changes from -10v to +10v
 

Re: MCP3301 measuring +-5v with respect to ground

share your schematic with us.
 

by using difference amplifier will there be any ADC value loss
 

by using difference amplifier will there be any ADC value loss
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Applying 5V reference will necessarily result in not fully utilizing the ADC range with 5V rail-to-rail OPs. Using higher OP supply voltage brings up a problem of violating the ADC input voltage range. Best solution is probably a slightly lower Vref, e.g. 4 or 4.5 V and a rail-to-rail OP buffer. LM358 will hardly work in any case.

You could even translate +/-10V to single ended 0..5V ADC input with a passive voltage divider, using Vref=2.5V, but it's losing some ADC accuracy.
 

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