5.4

Unused channel

When one of the two channels of the TSB952 is not used, it must be properly connected in order to avoid internal

oscillations that can negatively impact the signal integrity on the other channel, as well as the current

consumption. As the TSB952 is unity gain stable, the simplest solution is to set the unused channel in follower

and fix the positive input to any bias within the recommended operating range. A gain configuration can also be

used.

5.5

EMI rejection

The electromagnetic interference (EMI) rejection ratio, or EMIRR, describes the EMI immunity of operational

amplifiers. An adverse effect that is common to many op amps is a change in the offset voltage as a result of RF

signal rectification. EMIRR is defined in Eq. (2):

EMIRR=20.log Vin_ppΔVio

(2)

The TSB952 has been specially designed to minimize susceptibility to the EMIRR and shows a low sensitivity. As

visible in Figure 44, the EMI rejection ratio has been measured on both the inputs and the output, from 400 MHz

to 2.4 GHz.

Figure 44. EMIRR on In+ and In- pins

EMIRR performance might be improved by adding small capacitances (in the pF range) on the inputs, power

supply, and output pins. These capacitances help minimize the impedance of these nodes at high frequencies.

TSB952

Application information

DS14576 - Rev 1

page 19/36