'

AOL

Gmin

fd

f1

fu

f2

fu

fGBWP

UNITY-GAIN STABLE OP AMP

DECOMPENSATED OP AMP

1k

100k

100M

-20

20

100

10M

1M

10k

80

40

0

60

FREQUENCY (Hz)

-20

20

100

80

40

0

60

1k

100k

100M

-20

20

100

10M

1M

10k

80

40

0

60

FREQUENCY (Hz)

GAIN

PHASE

-20

20

100

80

40

0

60

LMV793, LMV794

www.ti.com

SNOSAX6D – MARCH 2007 – REVISED MARCH 2013

Figure 41. LMV793 AVOL vs. Frequency

Figure 42. LMV796 AVOL vs. Frequency

Figure 41 shows the much larger 88 MHz bandwidth of the LMV793 as compared to the 17 MHz bandwidth of

the LMV796 shown in Figure 42. The decompensated LMV793 has five times the bandwidth of the LMV796.

What is a Decompensated Op Amp?

The differences between the unity gain stable op amp and the decompensated op amp are shown in Figure 43.

This Bode plot assumes an ideal two pole system. The dominant pole of the decompensated op amp is at a

higher frequency, f1, as compared to the unity-gain stable op amp which is at fd as shown in Figure 43. This is

done in order to increase the speed capability of the op amp while maintaining the same power dissipation of the

unity gain stable op amp. The LMV793/LMV794 have a dominant pole at 1.6 kHz. The unity gain stable

LMV796/LMV797 have their dominant pole at 300 Hz.

Figure 43. Open Loop Gain for Unity-Gain Stable Op Amp and Decompensated Op Amp

Copyright © 2007–2013, Texas Instruments Incorporated

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Product Folder Links: LMV793 LMV794