max97236 Maxim Integrated Products, Inc., max97236 Datasheet - Page 16

• Manufacturer Part Number: max97236
• Description: Audio Amplifier With Jack Detection
• Manufacturer: Maxim Integrated Products, Inc.

Audio Amplifier with Jack Detection
16
A passive MBH consists of a microphone with numerous
switches that connect different value resistors to ground.
The switched resistor and the microphone bias resistor
set up a voltage-divider that creates a unique voltage.
The on-chip ADC then encodes the voltage and reports
to the system.
Figure 8. MBH Timing
Figure 7. Passive MBH
PASSIVE MULTIBUTTON HEADSET (MBH): OTHER BUTTON, NORMAL SPEED, OR BUTTON HELD
PASSIVE MULTIBUTTON HEADSET (MBH): OTHER BUTTON, FAST SPEED
V BIAS
V
GND
GND
BIAS
Passive Multibutton Headset (MBH)
ADC CONVERT
ADC CONVERT
t
t
DEB
DEB
MIC BIAS
ADC
MAX97236
t
t
DELAY
DELAY
KEYPRESS SET KEY AND REPORT VALUE
t
AND REPORT VALUE
KEYPRESS SET KEY
DEB
A maximum 0.5I resistance between IC pins RING2 and
SLEEVE and the headset is required for proper operation
of the passive multibutton headset.
Figure 7
Figure 8
press on a passive MBH. Note that a keypress develops
a voltage that is above ground. The switch that shorts
the microphone bias to ground is handled like the hook
switch in the previous section.
t
DELAY
shows the timing for a fast or normal speed key-
shows the circuit diagram of a passive MBH.
t
DEB
KEY RELEASE SET KEY IRQ
t
DELAY
KEY RELEASE SET KEY IRQ