THS4532_16 Datasheet, PDF (35/58 Pages) Texas Instruments – Ultra Low Power, Rail-to-Rail Output, Fully-Differential Amplifier

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THS4532
SLOS829A – FEBRUARY 2013 – REVISED JULY 2015
9.1.10 Audio Performance
The THS5432 provides excellent audio performance with very low quiescent power. To show performance in the
audio band, the device was tested with an audio analyzer. THD+N and FFT tests were run at 1-Vrms output
voltage. Performance is the same on both 2.7-V and 5-V supply. Figure 81 is the test circuit used, and Figure 82
and Figure 83 show performance of the analyzer. In the FFT plot the harmonic spurs are at the testing limit of the
analyzer, which means the THS5432 is actually much better than can be directly measured. Because the
THS5432 distortion performance cannot be directly measured in the audio band it is estimated from
measurement in high noise gain configuration correlated with simulation.
V_IN±
R_G
100 pF
R_F
10
V_OUT±
V_S+
From Analyzer
0.22 F
+
V_OCM
±
THS4532
To Analyzer
V_IN+
R_G
10
V_OUT+
100 pF
R_F
Figure 81. THS5432 Audio Analyzer Test Circuit
−95
−97
−99
−101
−103
No Weighting
A−Weighting
V_S = 5 V
G = 1 V/V
V_OUT = 1 V_RMS
R_F = 2 kΩ
R_L = 600 Ω
−105
−107
−109
−111
−113
−115
0
5k
10k
15k
20k
24k
Frequency (Hz)
G070
Figure 82. THD+N on Audio Analyzer, 10 Hz to 24 kHz
0
−10
V_S = 5 V
−20
G = 1 V/V
−30
V_OUT = 1 V_RMS
−40
R_F = 2 kΩ
−50
R_L = 600 Ω
−60
−70
−80
−90
−100
−110
−120
−130
−140
0
5k
10k
15k
20k
24k
Frequency (Hz)
G071
Figure 83. 1-kHz FFT Plot on Audio Analyzer
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