The addition of a line driver to the system is straight forward when using the THS6222 and the THVD8000. For all higher voltage interface systems, regardless if they are 110 V or 600 V, can be implemented in either configuration shown in Figure 1-1 and Figure 1-2. Figure 3-1 and Figure 3-2 show how to connect the signal pathways between the THVD8000 and the THS6222.

Both systems shown, operate in a similar way. For ease of design and less potential issues with integration the approach in Figure 3-2 is best; however, it is possible to use Figure 3-2 to achieve the same end goal with less THVD8000 Transceivers. Not shown, in the previous figures, is the integrated common mode buffer of the THS6222 which DC-couples the inputs to mid-supply of the device.

The differential gain (Av) of the line should set RF1 = RF2; the differential gain is . The standard Av = 10 (RF1 = RF2 = 1240Ω; RG = 274 Ω) is used when integrating the THVD8000 or THVD8010; as the output current drive is what’s most necessary for this application so higher gains than the standard 10V/V are typically unneeded.

Signal chain connections aside, both the THVD8000/8010 and the THS6222 have different control modes that will be switched during operation. For the THVD8000/8010 this is going to be the MODE pin and for the THS6222 it is the BIAS1 and BIAS2 pins. The THVD8000/8010 mode pin lets the device switch between transmit and receive modes while the BIAS pins for the THS6222 set the bias current consumption – where higher bias currents means more power drawn and higher performance with respect to linearity for the operational amplifier. Please see Table 3-1 on system configurations:

This mode table is accurate regardless if you are using the implementation from Figure 3-1 or Figure 3-2

With the basis of adding a line driver discussed - the next step is to talk about how the driver and receive pathways connect with the protection and high voltage interface.