OPA1652_16 Datasheet, PDF (20/42 Pages) Texas Instruments – Audio Operational Amplifiers

OPA1652, OPA1654
SBOS477A – DECEMBER 2011 – REVISED AUGUST 2016
Application Information (continued)
R₁
R₂
Signal Gain = 1+ ^R2
R₁
Distortion Gain = 1+ ^R2
R₁ II R₃
R₃
OPA165x
Generator
Output
Analyzer
Input
V_O = 3 V_RMS
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SIGNAL DISTORTION
GAIN
GAIN
R₁
R₂
R₃
+1
101
Â¥
1 kW 10 W
-1
101
4.99 kW 4.99 kW 49.9 W
+10
110
549 W 4.99 kW 49.9 W
Audio Precision
System Two⁽¹⁾
with PC Controller
Load
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(1) For measurement bandwidth, see Figure 7 through Figure 12.
Figure 40. Distortion Test Circuit
8.1.3 Capacitive Loads
The dynamic characteristics of the OPA1652 and OPA1654 have been optimized for commonly encountered
gains, loads, and operating conditions. The combination of low closed-loop gain and high capacitive loads
decreases the phase margin of the amplifier and can lead to gain peaking or oscillations. As a result, heavier
capacitive loads must be isolated from the output. The simplest way to achieve this isolation is to add a small
resistor (R_S equal to 50 Ω, for example) in series with the output.
This small series resistor also prevents excess power dissipation if the output of the device becomes shorted.
Figure 19 illustrates a graph of Small-Signal Overshoot vs Capacitive Load for several values of R_S. Also, refer to
Feedback Plots Define Op Amp AC Performance (SBOA015), available for download from the TI website, for
details of analysis techniques and application circuits.
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