Datasheet

MAX13335E/MAX13336E
Dual Automotive Differential Audio Receivers
with I
2
C Control and Diagnostics
21
Audio Presence Detection
When the device is used in an auxiliary input ampli-
fier, it can detect if audio is present at the inputs so the
downstream DSP does not have to continuously convert
the analog signal to digital in order to monitor the audio
stream. This can save two ADC inputs as the auxiliary
input can be muxed with another audio stream that is
mutually exclusive. To do this, perform the following steps:
1) Set the gain in the GAIN register based on the
required input audio level where the APD threshold is
exceeded. The threshold is set to 200mV
RMS
/G_[3:0].
2) Set API bit in the CTRL0 register to enable the APD
interrupt.
When the input audio level exceeds 200mV
RMS
/G_[3:0]
the INT pin is asserted. The microcontroller can read
back the STAT0 register to check for APD = 1.
Figure 11. Diagnostic Setup for Local Jack Sense
V
IDH
D1
L
R
C
D0
D1[3:0] ≥ 0010
V
IDL
97µA
V
IDH
DH0
D0[3:0] = 1110
DL0
V
IDL
40µA TO
705µA
MAX13335E/MAX13336E