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Ver.6

http://www.njr.com/

NJU77240/NJU77241/NJU77242

・

EMIRR (EMI Rejection Ratio) Definition

EMIRR is a parameter indicating the EMI robustness of an OP-Amp. The definition of EMIRR is given by the following a

formula (1). We can grasp the tolerance of the RF signal by measuring an RF signal and offset voltage shift quantity.

VRF_PEAK ：RF Signal Amplitude [ VP ]

Δ

VIO ：Input offset voltage shift quantity [ V ]

Offset voltage shift is small so that a value of EMIRR is big. And it understands that the tolerance for the RF signal is high. In

addition, about the input offset voltage shift with the RF signal, there is the thinking that influence applied to the input terminal is

dominant. Therefore, generally the EMIRR becomes value that applied an RF signal to +INPUT terminal.

*For details, refer to " Application Note for EMI Immunity" in our HP: http://www.njr.com/

…

(1)

EMIRR=20∙log

ቆVRF_PEAK

|∆VIO|

ቇ

0

20

40

60

80

100

120

100M

1G

10G

Frequency [Hz]

EMIRR vs. Frequency

V+=3V, V-=0V, VREF=1.5V, VRF_PEAK=100mVPP

Figure3. EMIRR vs. Frequency