AD1983 Datasheet, PDF (14/16 Pages) Analog Devices – HD Audio SoundMAX Codec

AD1983
JACK PRESENCE DETECTION
The AD1983 uses one jack sense line for presence detection on
up to four external jacks. This enables software to determine if
there is a device plugged into a jack; then, the AD1983 sensing
engine can determine what type of device it is. Jack presence is
detected using a resistor tree arrangement outlined in the HD
Audio specification. Up to four jacks can be sensed on a single
sense line by using a different value resistor for each between
the sense line and ground (AVSS). Jacks must have normally-
open, isolated switches to use this method of jack presence
detection.
For proper operation there must be a 2.67 kΩ 1% resistor
connected between SENSE_A and AVDD. For this configuration
R1 and C1 should be installed; R2 should not be installed
(see Figure 3).
The specific resistor values for each jack are shown in Table 13.
To ensure accurate detection, use 1% tolerance resistors for all
jack presence circuitry.
Table 13. Jack Sense Mapping
SENSE_A
Resistor (1%)
Name
Port
5.1 kΩ
Line Out
D
10.0 kΩ
Line In
C
20.0 kΩ
Microphone
B
39.2 kΩ
Headphone Out
A
Node ID
(Hex)
05
09
08
06
An alternate method reduces the current for sensing by
connecting a single 2.67 kΩ 1% resistor between the SENSE_A
and SENSE_SRC pins. For this configuration R1 and C1 are not
installed; however, R2 is installed (see Figure 3).
It is recommended that designers place circuitry for both
sensing methods and only install one of the two options.
AD1983
AV_DD
AV_DD
22, 26
9
SENSE_A/SRC_B
21
SENSE_SRC
R1
2.67kΩ, 1%, 1/8W
TO JACKS FOR
R2 (DNE)
2.67kΩ, 1%, 1/8W
C1 ^{PORT A THROUGH PORT D}
1µF
17, 29
AV_SS
Figure 3. Jack Presence Detection
Rev. 0 | Page 14 of 16