lm4911qmm National Semiconductor Corporation, lm4911qmm Datasheet - Page 20

• Manufacturer Part Number: lm4911qmm
• Description: Stereo Headphone Amplifier For Automotive
• Manufacturer: National Semiconductor Corporation

www.national.com
As stated in the External Components section, R
junction with C
The high frequency pole is determined by the product of the
desired frequency pole, f
an A
which is much smaller than the LM4911QMM GBWP of
10MHz. This figure displays that is a designer has a need to
design an amplifier with higher differential gain, the
LM4911QMM can still be used without running into bandwidth
limitations.
Figure 4
amplifier output that drives the headphone jack sleeve and
ground. This resistor provides a ground path that supressed
f
C
H
i
= 20kHz * 5 = 100kHz
≥
V
= 1 and f
1 / (2
shows an optional resistor connected between the
π
FIGURE 6. The PCDN042 provides additional ESD protection beyond the 2000V shown in the
i
* 20kΩ * 20Hz) = 0.397µF; use 0.39µF.
creates a
H
= 100kHz, the resulting GBWP = 100kHz
H
, and the differential gain, A
Absolute Maximum Ratings for the V
i
in con-
V
. With
20
power supply hum. Thishum may occur in applications such
as notebook computers in a shutdown condition and con-
nected to an external powered speaker. The resistor's 100Ω
value is a suggested starting point. Its final value must be de-
termined based on the tradeoff between the amount of noise
suppression that may be needed and minimizing the addi-
tional current drawn by the resistor (25mA for a 100Ω resistor
and a 5V supply).
ESD PROTECTION
As stated in the Absolute Maximum Ratings, the
LM4911QMM has a maximum ESD susceptibility rating of
2000V. For higher ESD voltages, the addition of a PCDN042
dual transil (from California Micro Devices), as shown in
ure
6, will provide additional protection.
O
C output
301350b4
Fig-