Cirrus Logic CS42L73 - Manual (Page 51)

DS882F1 51
CS42L73
4.7 Analog Output Current Limiter
The CS42L73 features built-in current-limit protection for both the headphone and line output amplifiers. The
approximate current through VCP during the short circuit conditions shown in
Figure 23 and Figure 24 is
described in Table 3 .
Note: 100  is always required in series with the line-output amplifiers. These amplifiers must never be
shorted directly to ground.
While the values in Table 3 show that the device is protected from permanent damage during a short circuit,
they do not represent maximum specification. See “DC Electrical Characteristics” on page 21 .
4.8 Serial Ports
The three independent, highly configurable, serial ports XSP, ASP, and VSP communicate audio and voice
data to and from other devices in the system, such as application processors, Bluetooth transceivers, and
cell-phone modems.
4.8.1 Power Management
The XSP and ASP have separate power-down controls (PDN_XSP_SDOUT, PDN_XSP_SDIN, PDN_
ASP_SDOUT, and PDN_ASP_SDIN) for their input and output data paths. Separating power state con-
trols minimizes power consumption if only monoplex communication is required (e.g., music playback).
The VSP, being targeted for duplex voice communication, has a single power-down control, PDN_VSP.
4.8.2 I/O
Each serial port interface consists to four signals (x = X, A, or V):
• xSP_SCLK Serial data shift clock
• xSP_LRCK Left/right clock
• Identifies the start of each serialized data word
• Identifies where each channel (left or right) is located within the data
word when I²S format (refer to section “I²S Format” on page 55 ) is used
Amplifier R
S
( )
Maximum Current (mA)
HPOUTx
3.3 120
0 120
LINEOUTx 0 120
Table 3. Current through VCP with Varying Short Circuits
GND/AGND
R
S
I
VCP
R
S
HPOUTA
HPOUTB
GND/AGND
R
S
I
VCP
R
S
LINEOUTA
LINEOUTB
100 
100 
Figure 23. HP Short Circuit Setup Figure 24. Line Short Circuit Setup