INA321 OPA340 composed output buffer circuit 322

The circuit depicted in the figure consists of an OPA340 operational amplifier configured as a voltage follower, serving as an output buffer for the INA321/322 output. The optimal load impedance for the INA321/322 is 10k ohms or greater. A decrease in load impedance results in an increase in output current. The OPA340 can provide a maximum output voltage swing that is 50mV lower than the supply voltage and is capable of driving loads of up to 600 ohms.

The circuit employs the OPA340 as a voltage follower to enhance the output drive capability of the INA321/322 instrumentation amplifiers. The configuration ensures that the output voltage closely follows the input voltage, which is essential for maintaining signal integrity while driving lower impedance loads.

The INA321/322 series is designed for precision applications with a focus on high common-mode rejection and low offset voltage. The recommended load impedance of 10k ohms or greater helps to ensure that the output stage operates within its optimal range, where linearity and performance are maximized. When the load impedance is reduced below this threshold, the output current increases, which may lead to potential distortion or performance degradation if the circuit is not designed to handle such conditions.

The OPA340's output stage has a limitation, where the maximum output swing is 50mV below the supply voltage. This characteristic is critical in applications that require precise voltage levels, as it defines the maximum output voltage that can be achieved. The ability of the OPA340 to drive loads up to 600 ohms makes it suitable for a variety of applications, including those that require interfacing with other analog components or driving low-impedance inputs.

In summary, the combination of the INA321/322 and the OPA340 in this configuration provides a robust solution for applications requiring high precision and reliable output drive capabilities, particularly in environments where load conditions may vary. As shown in FIG constituted by OPA340 INA321/322 output buffer circuit. INA321/322 optimum load impedance 10k or more. When the load impedance decreases, the output current wil l increase. Op amp OPA340 constitute a voltage follower as an output buffer circuit for increasing the output drive capability INA321/322s. OPA340 maximum output voltage swing is lower than the supply voltage 50mV, able to drive up to 600 load.