SM73302_15 Datasheet, PDF (14/31 Pages) Texas Instruments – SM73302 88 MHz, Precision, Low Noise, 1.8V CMOS Input, Decompensated Operational Amplifier

SM73302
SNOSB93A – AUGUST 2011 – REVISED APRIL 2013
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100
100
PHASE
80
80
60
60
GAIN
40
40
20
20
0
0
-20
1k
10k 100k 1M 10M
FREQUENCY (Hz)
-20
100M
Figure 44. SM73302 A_VOL vs. Frequency
100
100
80
80
60
60
40
40
20
20
0
0
-20
1k
10k 100k 1M 10M
FREQUENCY (Hz)
-20
100M
Figure 45. LMP7715 A_VOL vs. Frequency
Figure 44 shows the much larger 88 MHz bandwidth of the SM73302 as compared to the 17 MHz bandwidth of
the LMP7715 shown in Figure 45. The decompensated SM73302 has five times the bandwidth of the LMP7715.
What is a Decompensated Op Amp?
The differences between the unity gain stable op amp and the decompensated op amp are shown in Figure 46.
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 f_d as shown in Figure 46. 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 SM73302 has a dominant pole at 1.6 kHz. The unity gain stable
LMP7715/LMP7716 have their dominant pole at 300 Hz.
DECOMPENSATED OP AMP
A_OL
UNITY-GAIN STABLE OP AMP
G_min
f_d
f₁
fu
f_GBWP
f₂
f_u^'
Figure 46. Open Loop Gain for Unity Gain Stable Op Amp and Decompensated Op Amp
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