lm4811mmx National Semiconductor Corporation, lm4811mmx Datasheet - Page 15

• Manufacturer Part Number: lm4811mmx
• Description: Dual 105mw Headphone Amplifier With Digital Volume Control And Shutdown Mode
• Manufacturer: National Semiconductor Corporation

Application Information
point. Thus, a frequency of 20Hz is used in the following
equations to ensure that the response is better than 0.5dB
down at 100Hz.
C
i
C
≥ 1 / (2π * 33 kΩ * 20 Hz) = 0.241µF; use 0.39µF. (4)
o
≥ 1 / (2π * 32Ω * 20 Hz) = 249µF; use 330µF.
(Continued)
FIGURE 3. Demo Board Schematic
(5)
15
The high frequency pole is determined by the product of the
desired high frequency pole, f
A
100kHz, the resulting GBWP = 398kHz which is much
smaller than the LM4811 GBWP of 1MHz. This figure dis-
plays that at the maximum gain setting of 3.98 or +12dB, the
LM4811 can be used without running into bandwidth
limitations.
V
. With a closed-loop gain of 3.98 or +12dB and f
H
, and the closed-loop gain,
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H
=