ISO122 / 124 and PGA102, isolated channel has a programmable gain circuit diagram

The circuit features grounds ISO122/124 and PGA102, with ISO150 forming a gain programmable channel isolation circuit. The input signal VIN is amplified by the instrumentation amplifier PGA102 to ISO122P, which then outputs VOUT from the isolation amplifier ISO102P. Two gain selection signals, A0 and A1, are used after the isolation provided by ISO150, allowing the gain of PGA102 to be set to 1, 10, or 100. The complete isolation of the signal, power, ground, and gain control select pin contributes to the circuit's excellent anti-interference performance.

The described circuit integrates multiple components to achieve programmable gain and signal isolation, making it suitable for sensitive applications where noise immunity is crucial. The ISO122 and ISO124 are precision isolation amplifiers that provide high voltage isolation while maintaining signal integrity. These amplifiers are particularly useful in applications where ground loops or common-mode voltages can distort the signal.

The PGA102 is a programmable gain amplifier that allows for precise gain settings, which can be adjusted via digital control signals A0 and A1. This flexibility enables the circuit to adapt to various signal levels, ensuring optimal performance across a range of input conditions. The gain options of 1, 10, or 100 allow for versatility in applications, accommodating both low-level and higher-level signals.

The isolation provided by ISO150 enhances the circuit's robustness against electromagnetic interference (EMI) and radio frequency interference (RFI), which are common challenges in electronic systems. By isolating the input from the output, the circuit minimizes the risk of noise coupling, thus preserving the fidelity of the amplified signal.

In summary, this circuit design effectively combines gain programmability with high-performance isolation, making it well-suited for precision measurement systems, medical instrumentation, and industrial applications where signal integrity and noise immunity are paramount. The careful arrangement of components ensures that the circuit operates reliably under varying environmental conditions and input signal characteristics.As shown in FIG grounds ISO122 / 124 and PGA102, ISO150 constituted with a gain programmable channel isolation circuit. After the input signal VIN is amplified by instrumentation amplifier PGA102 to ISO122P, after ISO102P isolation amplifier output VOUT. Two gain selection signals A0, A1 by the isolation after ISO150 added PGA102, PGA102 gain is set to (1, 10 or 100).

Because the signal, power, ground and the output of the input signal, power, ground and gain control select pin completely isolated, so a good anti-interference performance of the circuit.