Single-ended output devices

When designing isolated voltage-sensing circuits with industry-standard isolated amplifiers such as the AMC1311, a common challenge is converting the differential output of the isolated amplifier to single ended in order to interface directly with the analog-to-digital converter (ADC) inside the microcontroller (MCU). This can be costly and consume extra PCB space.

To conserve board space, the AMC0311R-Q1, AMC0311S-Q1, AMC0330R-Q1 and AMC0330S-Q1 devices help save system-level costs and reduce solution size by removing the need for a differential- to single-ended conversion circuit, which typically consists of an operational amplifier and a reference voltage (see Figure 3).

Figure 4 shows the pinout of these single-ended devices.

Along with the board space savings that come with the AMC0311R-Q1 and AMC0330R-Q1 devices, their ratiometric output enables a variable output gain, providing an output swing from the isolated voltage-sensing device that follows the reference voltage of the ADC inside the MCU, as shown in Figure 5. This enables the use of the ADC’s full dynamic range for improved resolution measurements.

For more information on integrated resistor devices, see the application note, Isolated Amplifiers with Differential, Single-Ended Fixed Gain and Ratiometric Outputs for Voltage Sensing Applications.