TSZ181ILT datasheet(22/43 Pages) STMICROELECTRONICS

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5.9

EMI rejection ration (EMIRR)

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.

The TSZ18x has been specially designed to minimize susceptibility to EMIRR and show an extremely good

sensitivity. Figure 55. EMIRR on IN+ pin shows the EMIRR IN+, Figure 56. EMIRR on IN- pin shows the EMIRR

IN- of the TSZ18x measured from 10 MHz up to 2.4 GHz.

Figure 55. EMIRR on IN+ pin

Figure 56. EMIRR on IN- pin

5.10

1/f noise

1/f noise, also known as pink noise or flicker noise, is caused by defects, at the atomic level, in semiconductor

devices. The noise is a non-periodic signal and it cannot be calibrated. So for an application requiring precision, it

is extremely important to take this noise into account.

1/f noise is a major noise contributor at low frequencies and causes a significant output voltage offset when

amplified by the noise gain of the circuit. But, the TSZ18x, thanks to its chopper architecture, rejects 1/f noise and

thus makes this device an excellent choice for DC high precision applications.

As shown in Figure 28. Noise 0.1 - 10 Hz vs. time, 0.1 Hz to 10 Hz amplifier voltage noise is only 400 nVpp for a

VCC = 5 V. Figure 29. Noise vs. frequency and Figure 30. Noise vs. frequency and temperature show the voltage

noise density of the amplifier with no 1/f noise on a large bandwith. Figure 57. Noise vs frequency between 0.1

and 10 Hz exhibiting no 1/f noise below depicts noise vs frequency between 0.1 and 10 Hz exhibiting no 1/f noise.

TSZ181, TSZ182

EMI rejection ration (EMIRR)

DS11863 - Rev 5

page 22/43

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