Butterworth Filter

Note:

Transformers are used to change the single ended signals to differential signal or vice versa. On this EVM, they can be populated according to the application or the experiment. The VOCM pin of the device may be connected to the center-tap of the transformer, or maybe set via an external source such

as Vref of a data converter. If the VOCM pin is not connected to an external source, it will be set at the center point of the power supply. For example, if

±5 sources are used, the VOCM level will be set to zero.

2.7 Butterworth Filter

An example of a Butterworth filter implemented with multiple feedback archi- tecture is provided. The following circuit is implemented on the EVM board. The following figures represent the circuit configuration and the component values. The corner frequency of the filter (±3dB) is set at 1 MHz.

For verification of jumper locations and other bypass components, see the complete EVM schematic in Figure 1±2.

Figure 2±4. Multiple Feedback Filter Circuit

±1 dBm

787Ω

220 pF

787Ω

787 Ω
	100 pF
	VCC
732 Ω		5 V	100 Ω
	+	±
		±
732 Ω	THS4130
732 Ω	±	+
	±
		±5 V	100 Ω

VEE

100 pF

787Ω

2-6	Using the THS4130 EVM