JAJSC60F April 2016 – June 2024 THS6212
PRODUCTION DATA
Figure 7-4 shows an example of a dual-supply downstream driver with a synthesized output impedance circuit. The THS6212 is configured as a differential gain stage to provide a signal drive to the primary winding of the transformer (a step-up transformer with a turns ratio of 1:n is shown in Figure 7-4). The main advantage of this configuration is the cancellation of all even harmonic-distortion products. Another important advantage is that each amplifier must only swing half of the total output required driving the load.
The analog front-end (AFE) signal is ac-coupled to the driver, and the noninverting input of each amplifier is biased to the mid-supply voltage (ground in this case). In addition to providing the proper biasing to the amplifier, this approach also provides a high-pass filtering with a corner frequency that is set at 5 kHz in this example. Because the signal bandwidth starts at 26 kHz, this high-pass filter does not generate any problems and has the advantage of filtering out unwanted lower frequencies.