MAX97236EVKIT+ Maxim Integrated Products, MAX97236EVKIT+ Datasheet - Page 12

• Manufacturer Part Number: MAX97236EVKIT+
• Description: Audio Modules & Development Tools MAX97236 Eval Kit
• Manufacturer: Maxim Integrated Products

Specifications of MAX97236EVKIT+

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Audio Amplifier with Jack Detection
A short on the right audio output does not shut down the
left audio channel. A short on the audio output does not
shut down the right audio channel. This ensures that a
mono audio plug does not damage the chip, but allows
audio to be heard through the other channel output. A
short is considered anything below 4I for a time period
of 100ms.
The headphone amplifier features output ground sens-
ing for improved crosstalk performance. Crosstalk is
improved by at least 20dB, between the audio channels,
which all share a common jack ground.
the audio signal path from the filter through the amplifier
with volume control and the ground sense.
The headphone amplifiers employ a lowpass filter to
remove out-of-band noise from the audio DAC driving
the headphone inputs. The filter attenuates frequencies
above 85kHz.
The IC features a 64-step volume control with a resolu-
tion of 1dB/step from +6dB down to -54dB and 2dB/step
from -54dB to -60dB.
volume control.
Volume slewing breaks up large volume changes into the
smallest available step size as it goes through each gain
level between the initial and final volume setting. Volume
Figure 2. Headphone Amplifier Signal Path
12
IN_
Headphone Amplifier Volume Control
Headphone Amplifier Input Filter
MAX97236
Figure 3
Audio Short-Circuit Protection
Headphone Volume Slewing
shows the I/O curve of the
Ground Sense
Figure 2
RING2
OR SLEEVE
PGND
RING1
OR TIP
shows
slewing also occurs at device turn-on and turn-off when
enabled. During turn-on, the volume is set to mute before
the output is enabled. Once the output is on, the volume
ramps to the programmed level. At turn-off, the volume is
ramped to mute before the output is disabled.
As briefly described in the last section, the VSEN (vol-
ume slew enable) bit decides whether each volume step
is used when changing volume settings or whether the
final volume setting jumps to the new value after writing.
The volume slew enable function is used in conjunction
with the zero-crossing detection enable (ZDEN).
Examples:
VSEN = 0, ZDEN = 0, both functions on: The volume
changes one gain step at a time. The gain only changes
at the zero crossing of the audio signal.
VSEN = 0, ZDEN = 1: The volume changes one gain
step at a time.
VSEN = 1, ZDEN = 0: New volume is asserted as soon
as audio signal has gone through a zero crossing (or
100ms after the last gain change, whichever comes first).
VSEN = 1, ZDEN = 1: New volume is asserted as soon
as the I
Zero-crossing detection is implemented on the head-
phone amplifier volume control to prevent large glitches
when volume changes are made. Instead of making
a volume change immediately when requested, the
change is made when the audio signal has a zero cross-
ing or after 100ms, whichever comes first.
Figure 3. Headphone Volume Control Input/Output Transfer Function
2
C command is received.
Headphone Volume Zero-Crossing Detection
-10
-20
-30
-40
-50
-60
-70
10
0
0
10
20
STEP NUMBER
30
40
50
60
70