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LM741: Milivolt source

HARESH PATIL
Prodigy 120 points

Part Number: LM741
Other Parts Discussed in Thread: TLV333, DAC081C081

Hello Team TI , 

We want to create the milivolt source, to source the another circuit from the range of 1mV to 20mV with the step size of 1mV. also the circuit should not provide the error >10%. 

can you please provide the schematic or any other IC available at TI with schematic ?  

  • 0
    Guru 321960 points

    How does your circuit choose which step to output? Most DACs are controlled through I²C or SPI.

    It would be hard to find a DAC with an offset voltage of less than 0.1 mV. So I'd suggest to use a simple DAC like the DAC081C081, and to use a resistor divider to scale its output range down to 20 mV. If the output needs to be loaded, buffer it with a voltage follower, e.g., TLV333.

  • 0
    TI__Mastermind 27868 points

    Haresh,

    Clemens has a good point.  If you want automatic control you will need a digital-to-analog converter (DAC).  Most DAC devices output larger voltages like 0V to 5V.  You can use a voltage divider to divide the output down to a 20mV level.  For a 5V signal, a 1kΩ and 249kΩ resistor can be used to reduce the signal level to 20mV (V = 5V*1k/(1k + 249k) = 20mV).  Note that no DAC will have 20 different values (codes).  DACs always have a binary number of codes (8 bit DAC has 2^8 = 256 different values).  If you want a simple circuit you could put a string of resistors with a jumper on each resistor (see attached).  This circuit has many components but is conceptually simple (see attached TINA circuit).  

    simple 20mV generator.TSC

    Best regards,

    Art