FBM215 P0917TQ High Precision Operator

The current value of FBM215 P0917TQ is too small, the output signal will be very small during the test, in order to make the measured signal meet the requirements of A/D it is necessary to increase the amplification of the amplifier circuit, which increases the error of the system. Considering the above two reasons, the current value of the constant current source in this system is set at 0.5 mA. The constant current source circuit design uses the TLC2652 high-precision chopper stabilised zero operational amplifier [2] and voltage reference source TL431.

The FBM215 P0917TQ chopper-stabilised zero operation gives it excellent DC characteristics, out-of-phase voltage and its drift, common-mode voltage, low-frequency noise, etc. The TL431 is a three-terminal adjustable voltage reference source with good thermal stability, and its output voltage can be set within the range of 2.5 V to 36 V. The TLC2652 is a high-precision chopper-stabilised operational amplifier [2] and a voltage reference source TL431.

FBM215 P0917TQ in the design of constant current source, the voltage reference source TL431 so that the voltage at the two ends of A and B is 2.5 V, the point B is equal to the potential of the TLC2652’s pin 3, while the TLC2652’s pin 3 and its pin 2 is false-short, i.e., the 3-pin and the 2-pin are equal in potential, which also corresponds to the point B and the 2-pin potential of the TLC2652 is equal to the point B, i.e., the voltage at the ends of R1 is equal to the voltage at the ends of A, The voltage at both ends of R1 is equal to the voltage at both ends of A and B, which is also 2.5V, so that the current I1 flowing through R1 can be calculated as 0.5mA.