TPA6211A1-Q1_16 Datasheet, PDF (21/33 Pages) Texas Instruments – TPA6211A1-Q1 3.1-W Mono Fully Differential Audio Power Amplifier

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TPA6211A1-Q1
SBOS555C – JUNE 2011 – REVISED AUGUST 2016
f_c(LPF)
1
2SR_aC_a
(29)
Therefore,
C_a
1
2S 1k: f_c(LPF)
(30)
Substituting 10 kHz for f_c(LPF) and solving for C_a:
C_a = 160 pF
(31)
Figure 33 is a bode plot for the band-pass filter in the previous example. Figure 38 shows how to configure the
TPA6211A1-Q1 device as a band-pass filter.
AV
12 dB
9 dB
+20 dB/dec
−40 dB/dec
−20 dB/dec
f_c(HPF) = 100 Hz
f_c(LPF) = 10 kHz
f
Figure 33. Bode Plot
8.2.1.2.5 Decoupling Capacitor (C_S)
The TPA6211A1-Q1 device is a high-performance CMOS audio amplifier that requires adequate power supply
decoupling to ensure the output total harmonic distortion (THD) is as low as possible. Power-supply decoupling
also prevents oscillations for long lead lengths between the amplifier and the speaker. For higher frequency
transients, spikes, or digital hash on the line, a good low equivalent-series-resistance (ESR) ceramic capacitor,
typically 0.1 µF to 1 µF, placed as close as possible to the device V_DD lead works best. For filtering lower
frequency noise signals, a 10-µF or greater capacitor placed near the audio power amplifier also helps, but is not
required in most applications because of the high PSRR of this device.
8.2.1.2.6 Using Low-ESR Capacitors
Low-ESR capacitors are recommended throughout this applications section. A real (as opposed to ideal)
capacitor can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this
resistor minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this
resistance the more the real capacitor behaves like an ideal capacitor.
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