LM4906_14 Datasheet, PDF (12/21 Pages) Texas Instruments – 1W, Bypass-Capacitor-less Audio Amplifier with Internal Selectable Gain

LM4906, LM4906LDBD, LM4906MMBD
SNAS191D – MAY 2004 – REVISED JANUARY 2005
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The final design step is to address the bandwidth requirements which must be stated as a pair of −3dB
frequency points. Five times away from a −3dB point is 0.17dB down from passband response which is better
than the required ±0.25dB specified.
f_L = 100Hz / 5 = 20Hz
f_H = 20kHz * 5 = 100kHz
As stated in the External Components Description section, R_in (20k) in conjunction with C₂ create a highpass
filter.
C₂ ≥ 1 / (2π*20kΩ*20Hz) = 0.397µF; use 0.39µF
Figure 26. REFERENCE DESIGN BOARD SCHEMATIC
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