Datasheet
SLAS412− DECEMBER 2003
www.ti.com
27
−100
−90
−80
−70
−60
−50
−40
−30
−20
−10
0
0 50 100 150 200 250 300 350
2 V
PP
THD − Total Harmonic Distortion − dB
P
O
− Output Power − mW
2.402 V
PP
Figure 23. THD vs Output Power Delivered to an an 8- Load (255C, AVDD = DRVDD = 3.3 V, DVDD = 1.8
V, DAC Output Swing Set to 2 V and 2.4V, and Short-Circuit Protection Disabled)
−100
−90
−80
−70
−60
−50
−40
−30
−20
−10
0
2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6
AVDD, DRVDD − V
THD − Total Harmonic Distortion − dB
Figure 24. THD vs AVDD, DRVDD Supply Voltage (255C When Driving a −1 dB, 1-kHz Sinewave From the
DAC Into an 8- Load, with DAC Output Swing Set to 2.4 V, and Short-Circuit Protection Disabled)
The ’AIC26 incorporates a programmable short-circuit detection/protection function with different modes of operation.
During the insertion or removal of a headphone plug from the jack, the output pins of the drivers may be accidentally shorted,
causing the part to potentially draw a huge current, which may cause the power supply voltages to dip. Bits D8−D7 of
REG−1DH/Page2 control how the short-circuit detection/protection operates in the ’AIC26. One option is to fully disable
short-circuit protection, which also enables the audio output drivers to deliver more power to a low-impedance load (such
as an 8-Ω speaker). However, care must be taken to prevent any short-circuit from occurring while the part is in this mode.
A second programmable configuration enables current-limiting in the audio output drivers, so that excessive currents
cannot be provided if the outputs are shorted. It also enables the internal short-circuit detection function, which can detect
excess current being drawn from the drivers and set a short-circuit detect flag (Page2, REG−1DH, bit D6). This flag can
be read by the user to power down the drivers if desired. This flag is cleared only if the short-circuit condition is removed.
If the user does not monitor this flag and powers down the drivers when a short-circuit occurs, the current-limiting prevents
excessive currents from being drawn, but power dissipation is higher due to this limited current flowing through the short.