max9724c Maxim Integrated Products, Inc., max9724c Datasheet - Page 13

• Manufacturer Part Number: max9724c
• Description: Low Rf Susceptibility Directdrive Stereo Head- Phone Amplifier With 1.8v Compatible Shutdown
• Manufacturer: Maxim Integrated Products, Inc.

The MAX9724C can be used as an audio line driver
capable of providing 2V
gle 5V supply (see Figure 4 for the RMS Output Voltage
vs. Supply Voltage plot). 2V
level, first used in CD players, but now common in DVD
and set-top box (STB) interfacing standards. A 2V
Figure 4. RMS Output Voltage vs. Supply Voltage
Figure 5. MAX9724C Line Out Amplifier and Filter Block Configuration
phone Amplifier with 1.8V Compatible Shutdown
Low RF Susceptibility DirectDrive Stereo Head-
Lineout Amplifier and Filter Block
3.5
3.0
2.5
2.0
1.5
2.5
f
R
THD+N = 1%
IN
L
______________________________________________________________________________________
= 1kHz
= 10kΩ
3.0
STEREO
DAC
RMS OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
RMS
SUPPLY VOLTAGE (V)
3.5
RIGHT
AUDIO
INPUT
LEFT
AUDIO
INPUT
RMS
into 10kΩ loads with a sin-
4.0
LIMITED BY ABS.
MAXIMUM RATINGS
is a popular audio line
1μF
1μF
4.5
5.0
7.5kΩ
7.5kΩ
1.2nF
1.2nF
5.5
7.5kΩ
7.5kΩ
RMS
INL
INR
sinusoidal signal equates to approximately 5.7V
which means that the audio system designer cannot
simply run the lineout stage from a (typically common)
5V supply—the resulting output swing would be inade-
quate. A common solution to this problem is to use op
amps driven from split supplies (±5V typically), or to
use a high-voltage supply rail (9V to 12V). This can
mean adding extra cost and complexity to the system
power supply to meet this output level requirement.
Having the ability to derive 2V
even 3.3V supply, can often simplify power-supply
design in some systems.
When the MAX9724C is used as a line driver to provide
outputs that feed stereo equipment (receivers, STBs,
notebooks, and desktops) with a digital-to-analog con-
verter (DAC) used as an audio input source, it is often
desirable to eliminate any high-frequency quantization
noise produced by the DAC output before it reaches
the load. This high-frequency noise can cause the input
stages of the line-in equipment to exceed slew-rate lim-
itations or create excessive EMI emissions on the
cables between devices.
15kΩ
15kΩ
MAX9724C
220pF
220pF
OUTL
OUTR
10kΩ
10kΩ
LINE IN DEVICE
RMS
from a 5V supply, or
P-P
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