alc203-lf Realtek Semiconductor Corporation, alc203-lf Datasheet - Page 41

• Manufacturer Part Number: alc203-lf
• Description: Two-channel Ac?97 2.3 Audio Codec
• Manufacturer: Realtek Semiconductor Corporation

9.8 Jack-Detect Function & Assignment for Jack
JD (Jack-Detect) is an internal, pulled high input pin used to decide if LINE_OUT should be auto muted. If JDE (Jack Detect
Enable) is set and ALC203 detects the JD is floating or pull high (JDS=1), the ALC203 will disable the analog output of
LINE_OUT even when the MX02 is not muted.
The first figure below shows an example of jack detect which can implement this function. If no audio plug is inserted in
HP_OUT jack, JD is detected as low, and LINE output is normal. If an audio plug is inserted, the ALC203 disables the LINE
output, , S/PDIF output, MONO_OUT, HP_OUT. This is useful for some PC applications, such as notebook and home based
computers.
If a headphone output jack is not implemented and HP_OUT is kept as floating, once JDE is enabled, LINE_OUT will be muted
unless JD is pulled low by a 10KΩ resistor (See second figure below). To resolve this, the Jack-Detect mute LINE_OUT
function is disabled after power up (default JDE is 0). This makes the ALC203 compatible with other AC’97 devices. Therefore,
it is the responsibility of software to enable this function if headphone jack detection is implemented.
Two-Channel AC’97 2.3 Audio Codec
HP-OUT-R
HP-OUT-L
JD
HP-OUT-R
HP-OUT-L
JD
+100uf
+100uf
JD is Pulled Low by a 10KΩ Resistor
Example of a Jack Detect Circuit
If HP-OUT jack is not implemented,
JD must be pulled low to prevent JDS is set
4.7K
10K
4.7K
+
3.3u
37
4.7K
5
4
3
2
1
HP-OUT
ALC203 DataSheet
Rev1.6