Datasheet

g m s
Stereo +
Cellular
s
g m
Cellular
s
g s
Stereo
s
m = mic
s = speaker
g = virtual ground
1 PF
EXT_MIC
HP_L
HP_R
HP_VMID_FB
HP_VMID
LM49370
MIC_DET
EXT_MIC_BIAS
2.2 k:
3.3/2.8/2.5V
1.2/1.5V
Connection for OCL Mode (DC-Coupled) Headset Detection
g m s
Stereo +
Cellular
s
g m
Cellular
s
g s
Stereo
s
m = mic
s = speaker
g = ground (A_V
SS
)
1 k:
47 PF
1 PF
EXT_MIC
HP_L
HP_R
HP_VMID_FB
HP_VMID
1 k:
MIC_DET
EXT_MIC_BIAS
2.2 k:
2.0/2.5V
A_V
DD
/2
Connection for Non-OCL Mode (AC-Coupled) Headset Detection
47 PF
LM49370
LM49370
SNAS356D –FEBRUARY 2007–REVISED MARCH 2012 www.ti.com
The wiring of the headset jack to the LM49370 will depend on the intended mode of the headphone amplifier:
Figure 17. Connection of Headset Jack to LM49370 Depends on the Mode of the Headphone Amplifier.
In non-OCL mode, two 1kΩ resistors are optional and not needed if chip is active without headset event
detection in Basic Register (0x00h) bits 1:0. If chip is active with headset event detection, these two resistors set
an internal threshold voltage for a comparator that produces the headphone detect pulse. The value of these
should be 1kΩ with tolerance of ±10% or better.
STATUS REGISTER
This register is used to report the status of the device.
Table 31. STATUS (0x18h)
(1)(2)
Bits Field Description
0 HEADSET This field is high when headset presence is detected (only valid if the detection system is enabled).
(1)
1 STEREO_ This field is high when a headset with stereo speakers is detected (only valid if the detection system is
HEADSET enabled).
(1)
2 MIC This field is high when a headset with a microphone is detected (only valid if the detection system is
enabled).
(1)
(1) The detection IRQ is cleared when this register has been written to.
(2) This field is cleared whenever the STATUS (0x18h) register has been written to.
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