0

20

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10M

100M

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Frequency (Hz)

C004

17

OPA187, OPA2187, OPA4187

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SBOS807 – DECEMBER 2016

Product Folder Links: OPA187 OPA2187 OPA4187

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Copyright © 2016, Texas Instruments Incorporated

Feature Description (continued)

7.3.5 EMI Rejection

The OPAx187 device uses integrated electromagnetic interference (EMI) filtering to reduce the effects of EMI

interference from sources such as wireless communications and densely-populated boards with a mix of analog

signal chain and digital components. EMI immunity can be improved with circuit design techniques; the OPAx187

benefits from these design improvements. Texas Instruments has developed the ability to accurately measure

and quantify the immunity of an operational amplifier over a broad frequency spectrum extending from 10 MHz to

6 GHz. Figure 38 shows the results of this testing on the OPAx187. Table 2 lists the EMIRR IN+ values for the

OPAx187 at particular frequencies commonly encountered in real-world applications. Applications listed in

Table 2 may be centered on or operated near the particular frequency shown. Detailed information can also be

found in EMI Rejection Ratio of Operational Amplifiers, available for download from www.ti.com.

Figure 38. EMIRR Testing

Table 2. OPAx187 EMIRR IN+ for Frequencies of Interest

FREQUENCY

APPLICATION/ALLOCATION

EMIRR IN+

400 MHz

Mobile radio, mobile satellite, space operation, weather, radar, ultra-high frequency

(UHF) applications

81.8 dB

900 MHz

Global system for mobile communications (GSM) applications, radio

communication, navigation, GPS (to 1.6 GHz), GSM, aeronautical mobile, UHF

applications

102.7 dB

1.8 GHz

GSM applications, mobile personal communications, broadband, satellite, L-band

(1 GHz to 2 GHz)

115.4 dB

2.4 GHz

industrial, scientific and medical (ISM) radio band, amateur radio and satellite, S-

band (2 GHz to 4 GHz)

150.7 dB

3.6 GHz

Radiolocation, aero communication and navigation, satellite, mobile, S-band

142.0 dB

5.0 GHz

802.11a, 802.11n, aero communication and navigation, mobile communication,

space and satellite operation, C-band (4 GHz to 8 GHz)

173.8 dB

7.3.6 Capacitive Load and Stability

The device dynamic characteristics are optimized for a range of common operating conditions. The combination

of low closed-loop gain and high capacitive loads decreases the amplifier phase margin and can lead to gain

peaking or oscillations. As a result, larger capacitive loads must be isolated from the output. The simplest way to

analysis techniques and application circuits, refer to Feedback Plots Define Op Amp AC Performance, available

for download from www.ti.com.